feat: v2 rewrite — hexagonal arch, ActivityPub federation, NATS, deployment-ready (#1)

crates/adapters/activitypub-base/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "activitypub-base"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+tokio        = { workspace = true }
+futures      = { workspace = true }
+serde        = { workspace = true }
+serde_json   = { workspace = true }
+uuid         = { workspace = true }
+chrono       = { workspace = true }
+anyhow       = { workspace = true }
+tracing      = { workspace = true }
+async-trait  = { workspace = true }
+axum         = { workspace = true }
+reqwest      = { workspace = true }
+url          = { workspace = true }
+domain       = { workspace = true }
+
+activitypub_federation = "0.7.0-beta.11"
+enum_delegate          = "0.2"

crates/adapters/activitypub-base/src/activities.rs

@@ -0,0 +1,851 @@
+use activitypub_federation::{
+    config::Data,
+    fetch::object_id::ObjectId,
+    kinds::activity::{
+        AcceptType, CreateType, DeleteType, FollowType, RejectType, UndoType, UpdateType,
+    },
+    traits::Activity,
+};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+#[derive(Clone, Default, Debug, Serialize, Deserialize)]
+#[serde(rename = "Announce")]
+pub struct AnnounceType;
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
+#[serde(rename = "Like")]
+pub struct LikeType;
+
+impl Default for LikeType {
+    fn default() -> Self {
+        Self
+    }
+}
+
+use crate::actors::DbActor;
+use crate::data::FederationData;
+use crate::error::Error;
+use crate::repository::{FollowerStatus, FollowingStatus};
+
+// --- Follow ---
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct FollowActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: FollowType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: ObjectId<DbActor>,
+}
+
+#[async_trait::async_trait]
+impl Activity for FollowActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let target_url = self.object.inner();
+        let target_domain = match (target_url.host_str(), target_url.port()) {
+            (Some(host), Some(port)) => format!("{}:{}", host, port),
+            (Some(host), None) => host.to_string(),
+            _ => {
+                return Err(Error::bad_request(anyhow::anyhow!(
+                    "invalid follow target URL"
+                )));
+            }
+        };
+        if target_domain != data.domain {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "follow target is not a local actor"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        let _follower = self.actor.dereference(data).await?;
+        let local_actor = self.object.dereference(data).await?;
+
+        if data
+            .federation_repo
+            .is_actor_blocked(local_actor.user_id, self.actor.inner().as_str())
+            .await?
+        {
+            tracing::info!(actor = %self.actor.inner(), "ignoring follow from blocked actor");
+            return Ok(());
+        }
+
+        data.federation_repo
+            .add_follower(
+                local_actor.user_id,
+                self.actor.inner().as_str(),
+                FollowerStatus::Pending,
+                self.id.as_str(),
+            )
+            .await?;
+
+        tracing::info!(
+            follower = %self.actor.inner(),
+            local_user = %local_actor.user_id,
+            "follow request pending approval"
+        );
+        Ok(())
+    }
+}
+
+// --- Accept ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AcceptActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: AcceptType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: FollowActivity,
+}
+
+#[async_trait::async_trait]
+impl Activity for AcceptActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        if self.actor.inner() != self.object.object.inner() {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "Accept actor does not match Follow target"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        let local_user_id = crate::urls::extract_user_id_from_url(self.object.actor.inner())
+            .ok_or_else(|| Error::bad_request(anyhow::anyhow!("invalid actor URL in Follow")))?;
+        data.federation_repo
+            .update_following_status(
+                local_user_id,
+                self.actor.inner().as_str(),
+                FollowingStatus::Accepted,
+            )
+            .await?;
+
+        tracing::info!(remote_actor = %self.actor.inner(), "follow accepted by remote");
+        Ok(())
+    }
+}
+
+// --- Reject ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RejectActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: RejectType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: FollowActivity,
+}
+
+#[async_trait::async_trait]
+impl Activity for RejectActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        if self.actor.inner() != self.object.object.inner() {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "Reject actor does not match Follow target"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        if let Some(user_id) = crate::urls::extract_user_id_from_url(self.object.actor.inner()) {
+            data.federation_repo
+                .remove_following(user_id, self.actor.inner().as_str())
+                .await?;
+        }
+        tracing::info!(actor = %self.actor.inner(), "follow rejected");
+        Ok(())
+    }
+}
+
+// --- Undo ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct UndoActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: UndoType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: serde_json::Value,
+}
+
+#[async_trait::async_trait]
+impl Activity for UndoActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring Undo from blocked domain");
+            return Ok(());
+        }
+
+        let obj_type = self
+            .object
+            .get("type")
+            .and_then(|t| t.as_str())
+            .unwrap_or("");
+
+        match obj_type {
+            "Follow" => {
+                if let Some(obj_url) = self.object.get("object").and_then(|o| o.as_str())
+                    && let Ok(url) = Url::parse(obj_url)
+                    && let Some(user_id) = crate::urls::extract_user_id_from_url(&url)
+                {
+                    data.federation_repo
+                        .remove_follower(user_id, self.actor.inner().as_str())
+                        .await?;
+                }
+                data.object_handler
+                    .on_actor_removed(self.actor.inner())
+                    .await
+                    .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+                tracing::info!(actor = %self.actor.inner(), "unfollowed");
+            }
+            "Add" => {
+                let ap_id_str = self
+                    .object
+                    .get("object")
+                    .and_then(|o| o.get("id"))
+                    .and_then(|id| id.as_str())
+                    .or_else(|| self.object.get("id").and_then(|id| id.as_str()));
+
+                if let Some(ap_id_str) = ap_id_str
+                    && let Ok(ap_id) = Url::parse(ap_id_str)
+                {
+                    data.object_handler
+                        .on_delete(&ap_id, self.actor.inner())
+                        .await
+                        .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+                    tracing::info!(ap_id = %ap_id_str, "undo Add (watchlist remove)");
+                }
+            }
+            "Like" => {
+                if let Some(obj_url_str) = self.object.get("object").and_then(|o| o.as_str())
+                    && let Ok(obj_url) = Url::parse(obj_url_str)
+                    && obj_url.host_str().unwrap_or("") == data.domain
+                {
+                    data.object_handler
+                        .on_unlike(&obj_url, self.actor.inner())
+                        .await
+                        .unwrap_or_else(|e| {
+                            tracing::warn!(error = %e, "failed to process unlike");
+                        });
+                }
+                tracing::info!(actor = %self.actor.inner(), "received Undo(Like)");
+            }
+            other => {
+                tracing::debug!(kind = %other, "ignoring Undo of unknown activity type");
+            }
+        }
+
+        Ok(())
+    }
+}
+
+// --- Create ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: CreateType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: serde_json::Value,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) to: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) cc: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) bto: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) bcc: Vec<String>,
+}
+
+#[async_trait::async_trait]
+impl Activity for CreateActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        if let Some(attributed_to) = self.object.get("attributedTo").and_then(|v| v.as_str())
+            && let Ok(attributed_url) = Url::parse(attributed_to)
+            && &attributed_url != self.actor.inner()
+        {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "Create actor does not match object attributedTo"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        // Use the Note's own id, not the Create activity id (which ends in /activity).
+        // Delete activities reference the Note id, so they must match.
+        let ap_id = self
+            .object
+            .get("id")
+            .and_then(|v| v.as_str())
+            .and_then(|s| Url::parse(s).ok())
+            .unwrap_or_else(|| self.id.clone());
+        let actor_url = self.actor.inner().clone();
+        data.object_handler
+            .on_create(&ap_id, &actor_url, self.object)
+            .await
+            .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+        tracing::info!(actor = %actor_url, "received create activity");
+        Ok(())
+    }
+}
+
+// --- Delete ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct DeleteActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: DeleteType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: serde_json::Value,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) to: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) cc: Vec<String>,
+}
+
+#[async_trait::async_trait]
+impl Activity for DeleteActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let actor_domain = self.actor.inner().host_str().unwrap_or("");
+        let object_domain = match &self.object {
+            serde_json::Value::String(s) => Url::parse(s)
+                .ok()
+                .and_then(|u| u.host_str().map(|h| h.to_string()))
+                .unwrap_or_default(),
+            serde_json::Value::Object(o) => o
+                .get("id")
+                .and_then(|v| v.as_str())
+                .and_then(|s| Url::parse(s).ok())
+                .and_then(|u| u.host_str().map(|h| h.to_string()))
+                .unwrap_or_default(),
+            _ => String::new(),
+        };
+        if !object_domain.is_empty() && actor_domain != object_domain {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "Delete actor domain does not match object domain"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        let actor_url = self.actor.inner().clone();
+
+        // Extract object URL — handles plain string and Tombstone {"id":"...","type":"Tombstone"}
+        let object_url_str = match &self.object {
+            serde_json::Value::String(s) => s.clone(),
+            serde_json::Value::Object(o) => o
+                .get("id")
+                .and_then(|v| v.as_str())
+                .map(|s| s.to_string())
+                .unwrap_or_default(),
+            _ => String::new(),
+        };
+        let Ok(object_url) = Url::parse(&object_url_str) else {
+            tracing::warn!(actor = %actor_url, "Delete activity has unparseable object, ignoring");
+            return Ok(());
+        };
+
+        // Actor self-deletion: Mastodon sends Delete(actor_url) when an account is deleted.
+        if object_url == *self.actor.inner() {
+            data.object_handler
+                .on_actor_removed(&actor_url)
+                .await
+                .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+            tracing::info!(actor = %actor_url, "received Delete(actor) — remote account deleted");
+            return Ok(());
+        }
+
+        // Normal note deletion.
+        data.object_handler
+            .on_delete(&object_url, &actor_url)
+            .await
+            .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+        tracing::info!(object = %object_url, "received Delete(note)");
+        Ok(())
+    }
+}
+
+// --- Update ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct UpdateActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: UpdateType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: serde_json::Value,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) to: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) cc: Vec<String>,
+}
+
+#[async_trait::async_trait]
+impl Activity for UpdateActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        if let Some(attributed_to) = self.object.get("attributedTo").and_then(|v| v.as_str())
+            && let Ok(attributed_url) = Url::parse(attributed_to)
+            && &attributed_url != self.actor.inner()
+        {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "Update actor does not match object attributedTo"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        let ap_id = self
+            .object
+            .get("id")
+            .and_then(|v| v.as_str())
+            .and_then(|s| Url::parse(s).ok())
+            .unwrap_or_else(|| self.id.clone());
+        let actor_url = self.actor.inner().clone();
+        data.object_handler
+            .on_update(&ap_id, &actor_url, self.object)
+            .await
+            .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+        tracing::info!(actor = %actor_url, "received update activity");
+        Ok(())
+    }
+}
+
+// --- Announce ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AnnounceActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: AnnounceType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: Url,
+    pub(crate) published: Option<chrono::DateTime<chrono::Utc>>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) to: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) cc: Vec<String>,
+}
+
+#[async_trait::async_trait]
+impl Activity for AnnounceActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        let object_domain = self.object.host_str().unwrap_or("");
+        if object_domain != data.domain {
+            tracing::debug!(
+                actor = %self.actor.inner(),
+                object = %self.object,
+                "received Announce of non-local object — skipped (cross-server boost not supported)"
+            );
+            return Ok(());
+        }
+        data.federation_repo
+            .add_announce(
+                self.id.as_str(),
+                self.object.as_str(),
+                self.actor.inner().as_str(),
+                self.published.unwrap_or_else(chrono::Utc::now),
+            )
+            .await?;
+        data.object_handler
+            .on_announce_received(&self.object, self.actor.inner())
+            .await
+            .unwrap_or_else(|e| {
+                tracing::warn!(error = %e, "failed to process announce notification");
+            });
+        tracing::info!(actor = %self.actor.inner(), object = %self.object, "received announce");
+        Ok(())
+    }
+}
+
+// --- Like ---
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct LikeActivity {
+    pub id: Url,
+    #[serde(rename = "type")]
+    pub kind: LikeType,
+    pub actor: ObjectId<DbActor>,
+    pub object: Url,
+}
+
+#[async_trait::async_trait]
+impl Activity for LikeActivity {
+    type DataType = FederationData;
+    type Error = crate::error::Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring Like from blocked domain");
+            return Ok(());
+        }
+
+        // Only process if the liked object is on our instance.
+        if self.object.host_str().unwrap_or("") != data.domain {
+            return Ok(());
+        }
+
+        data.object_handler
+            .on_like(&self.object, self.actor.inner())
+            .await
+            .map_err(|e| crate::error::Error::from(anyhow::anyhow!(e)))?;
+
+        tracing::info!(actor = %self.actor.inner(), object = %self.object, "received like");
+        Ok(())
+    }
+}
+
+// --- Add ---
+
+#[derive(Clone, Default, Debug, Serialize, Deserialize)]
+#[serde(rename = "Add")]
+pub struct AddType;
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AddActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: AddType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: serde_json::Value,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) to: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub(crate) cc: Vec<String>,
+}
+
+#[async_trait::async_trait]
+impl Activity for AddActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring Add from blocked domain");
+            return Ok(());
+        }
+        let ap_id = self.id.clone();
+        let actor_url = self.actor.inner().clone();
+        data.object_handler
+            .on_create(&ap_id, &actor_url, self.object)
+            .await
+            .map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+        tracing::info!(actor = %actor_url, "received Add activity");
+        Ok(())
+    }
+}
+
+// --- Block ---
+
+#[derive(Clone, Default, Debug, Serialize, Deserialize)]
+#[serde(rename = "Block")]
+pub struct BlockType;
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct BlockActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: BlockType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: Url,
+}
+
+#[async_trait::async_trait]
+impl Activity for BlockActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            tracing::info!(actor = %self.actor(), "ignoring activity from blocked domain");
+            return Ok(());
+        }
+        if let Some(local_user_id) = crate::urls::extract_user_id_from_url(&self.object) {
+            let _ = data
+                .federation_repo
+                .remove_following(local_user_id, self.actor.inner().as_str())
+                .await;
+            let _ = data
+                .federation_repo
+                .remove_follower(local_user_id, self.actor.inner().as_str())
+                .await;
+        }
+        tracing::info!(actor = %self.actor.inner(), "received block — removed following and follower");
+        Ok(())
+    }
+}
+
+// --- Move (account migration) ---
+
+#[derive(Clone, Default, Debug, Serialize, Deserialize)]
+#[serde(rename = "Move")]
+pub struct MoveType;
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct MoveActivity {
+    pub(crate) id: Url,
+    #[serde(rename = "type", default)]
+    pub(crate) kind: MoveType,
+    pub(crate) actor: ObjectId<DbActor>,
+    pub(crate) object: Url,
+    pub(crate) target: Url,
+}
+
+#[async_trait::async_trait]
+impl Activity for MoveActivity {
+    type DataType = FederationData;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, _data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        if &self.object != self.actor.inner() {
+            return Err(Error::bad_request(anyhow::anyhow!(
+                "Move object must be the actor itself"
+            )));
+        }
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let domain = self.actor().host_str().unwrap_or("");
+        if data.federation_repo.is_domain_blocked(domain).await? {
+            return Ok(());
+        }
+        tracing::info!(
+            actor = %self.actor.inner(),
+            target = %self.target,
+            "received Move (account migration) — target noted"
+        );
+        Ok(())
+    }
+}
+
+// --- Inbox dispatch enum ---
+
+#[derive(Debug, Deserialize, Serialize)]
+#[serde(tag = "type")]
+#[enum_delegate::implement(Activity)]
+pub enum InboxActivities {
+    #[serde(rename = "Follow")]
+    Follow(FollowActivity),
+    #[serde(rename = "Accept")]
+    Accept(AcceptActivity),
+    #[serde(rename = "Reject")]
+    Reject(RejectActivity),
+    #[serde(rename = "Undo")]
+    Undo(UndoActivity),
+    #[serde(rename = "Create")]
+    Create(CreateActivity),
+    #[serde(rename = "Delete")]
+    Delete(DeleteActivity),
+    #[serde(rename = "Update")]
+    Update(UpdateActivity),
+    #[serde(rename = "Announce")]
+    Announce(AnnounceActivity),
+    #[serde(rename = "Add")]
+    Add(AddActivity),
+    #[serde(rename = "Block")]
+    Block(BlockActivity),
+    #[serde(rename = "Like")]
+    Like(LikeActivity),
+    #[serde(rename = "Move")]
+    Move(MoveActivity),
+}

crates/adapters/activitypub-base/src/actor_handler.rs

@@ -0,0 +1,25 @@
+use activitypub_federation::{
+    axum::json::FederationJson, config::Data, protocol::context::WithContext, traits::Object,
+};
+use axum::extract::Path;
+
+use crate::actors::{Person, get_local_actor};
+use crate::data::FederationData;
+use crate::error::Error;
+
+pub async fn actor_handler(
+    Path(username): Path<String>,
+    data: Data<FederationData>,
+) -> Result<FederationJson<WithContext<Person>>, Error> {
+    let ap_user = data
+        .user_repo
+        .find_by_username(&username)
+        .await
+        .map_err(Error::from)?
+        .ok_or_else(|| Error::bad_request(anyhow::anyhow!("user not found")))?;
+
+    let db_actor = get_local_actor(ap_user.id, &data).await?;
+    let person = db_actor.into_json(&data).await?;
+
+    Ok(FederationJson(WithContext::new_default(person)))
+}

crates/adapters/activitypub-base/src/actors.rs

@@ -0,0 +1,372 @@
+use activitypub_federation::{
+    config::Data,
+    fetch::object_id::ObjectId,
+    http_signatures::generate_actor_keypair,
+    kinds::actor::PersonType,
+    protocol::{public_key::PublicKey, verification::verify_domains_match},
+    traits::{Actor, Object},
+};
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+use crate::data::FederationData;
+use crate::error::Error;
+use crate::repository::RemoteActor;
+use crate::user::ApProfileField;
+
+#[derive(Debug, Clone)]
+pub struct DbActor {
+    pub user_id: uuid::Uuid,
+    pub username: String,
+    pub public_key_pem: String,
+    pub private_key_pem: Option<String>,
+    pub inbox_url: Url,
+    pub shared_inbox_url: Option<Url>,
+    pub outbox_url: Url,
+    pub followers_url: Url,
+    pub following_url: Url,
+    pub ap_id: Url,
+    pub last_refreshed_at: DateTime<Utc>,
+    pub bio: Option<String>,
+    pub avatar_url: Option<Url>,
+    pub banner_url: Option<Url>,
+    pub also_known_as: Option<String>,
+    pub profile_url: Option<Url>,
+    pub attachment: Vec<ApProfileField>,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct ApImageObject {
+    #[serde(rename = "type")]
+    pub kind: String,
+    pub url: Url,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Endpoints {
+    pub shared_inbox: Url,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ProfileFieldObject {
+    #[serde(rename = "type")]
+    pub kind: String,
+    pub name: String,
+    pub value: String,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Person {
+    #[serde(rename = "type")]
+    kind: PersonType,
+    id: ObjectId<DbActor>,
+    preferred_username: String,
+    inbox: Url,
+    outbox: Url,
+    followers: Url,
+    following: Url,
+    public_key: PublicKey,
+    name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    summary: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    icon: Option<ApImageObject>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    url: Option<Url>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    discoverable: Option<bool>,
+    manually_approves_followers: bool,
+    #[serde(skip_serializing_if = "Option::is_none", default)]
+    updated: Option<DateTime<Utc>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    endpoints: Option<Endpoints>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    image: Option<ApImageObject>,
+    #[serde(rename = "alsoKnownAs", skip_serializing_if = "Vec::is_empty", default)]
+    also_known_as: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    attachment: Vec<ProfileFieldObject>,
+}
+
+struct ActorUrls {
+    ap_id: Url,
+    inbox_url: Url,
+    shared_inbox_url: Option<Url>,
+    outbox_url: Url,
+    followers_url: Url,
+    following_url: Url,
+}
+
+impl ActorUrls {
+    fn build(base_url: &str, user_id: uuid::Uuid) -> Self {
+        let ap_id = crate::urls::actor_url(base_url, user_id);
+        Self {
+            inbox_url: Url::parse(&format!("{}/inbox", &ap_id)).expect("valid url"),
+            shared_inbox_url: Url::parse(&format!("{}/inbox", base_url)).ok(),
+            outbox_url: Url::parse(&format!("{}/outbox", &ap_id)).expect("valid url"),
+            followers_url: Url::parse(&format!("{}/followers", &ap_id)).expect("valid url"),
+            following_url: Url::parse(&format!("{}/following", &ap_id)).expect("valid url"),
+            ap_id,
+        }
+    }
+}
+
+pub async fn get_local_actor(
+    user_id: uuid::Uuid,
+    data: &Data<FederationData>,
+) -> Result<DbActor, Error> {
+    let user = data
+        .user_repo
+        .find_by_id(user_id)
+        .await
+        .map_err(Error::from)?
+        .ok_or_else(|| Error::not_found(anyhow::anyhow!("user not found: {}", user_id)))?;
+
+    let (public_key, private_key) = match data
+        .federation_repo
+        .get_local_actor_keypair(user_id)
+        .await?
+    {
+        Some(kp) => kp,
+        None => {
+            let kp = generate_actor_keypair()?;
+            data.federation_repo
+                .save_local_actor_keypair(user_id, kp.public_key.clone(), kp.private_key.clone())
+                .await?;
+            (kp.public_key, kp.private_key)
+        }
+    };
+
+    let ActorUrls {
+        ap_id,
+        inbox_url,
+        shared_inbox_url,
+        outbox_url,
+        followers_url,
+        following_url,
+    } = ActorUrls::build(&data.base_url, user_id);
+
+    Ok(DbActor {
+        user_id,
+        username: user.username,
+        public_key_pem: public_key,
+        private_key_pem: Some(private_key),
+        inbox_url,
+        shared_inbox_url,
+        outbox_url,
+        followers_url,
+        following_url,
+        ap_id,
+        last_refreshed_at: Utc::now(),
+        bio: user.bio,
+        avatar_url: user.avatar_url,
+        banner_url: user.banner_url,
+        also_known_as: user.also_known_as,
+        profile_url: user.profile_url,
+        attachment: user.attachment,
+    })
+}
+
+#[async_trait::async_trait]
+impl Object for DbActor {
+    type DataType = FederationData;
+    type Kind = Person;
+    type Error = Error;
+
+    fn id(&self) -> &Url {
+        &self.ap_id
+    }
+
+    fn last_refreshed_at(&self) -> Option<DateTime<Utc>> {
+        Some(self.last_refreshed_at)
+    }
+
+    async fn read_from_id(
+        object_id: Url,
+        data: &Data<Self::DataType>,
+    ) -> Result<Option<Self>, Self::Error> {
+        let user_id = match crate::urls::extract_user_id_from_url(&object_id) {
+            Some(id) => id,
+            None => return Ok(None),
+        };
+        let user = match data.user_repo.find_by_id(user_id).await {
+            Ok(Some(u)) => u,
+            _ => return Ok(None),
+        };
+
+        let keypair = data
+            .federation_repo
+            .get_local_actor_keypair(user_id)
+            .await?;
+
+        let (public_key, private_key) = match keypair {
+            Some(kp) => (kp.0, Some(kp.1)),
+            None => return Ok(None),
+        };
+
+        let ActorUrls {
+            ap_id,
+            inbox_url,
+            shared_inbox_url,
+            outbox_url,
+            followers_url,
+            following_url,
+        } = ActorUrls::build(&data.base_url, user_id);
+
+        Ok(Some(DbActor {
+            user_id,
+            username: user.username,
+            public_key_pem: public_key,
+            private_key_pem: private_key,
+            inbox_url,
+            shared_inbox_url,
+            outbox_url,
+            followers_url,
+            following_url,
+            ap_id,
+            last_refreshed_at: Utc::now(),
+            bio: None,
+            avatar_url: None,
+            banner_url: None,
+            also_known_as: None,
+            profile_url: None,
+            attachment: vec![],
+        }))
+    }
+
+    async fn into_json(self, data: &Data<Self::DataType>) -> Result<Self::Kind, Self::Error> {
+        let public_key = PublicKey {
+            id: format!("{}#main-key", &self.ap_id),
+            owner: self.ap_id.clone(),
+            public_key_pem: self.public_key_pem.clone(),
+        };
+
+        let icon = self.avatar_url.map(|url| ApImageObject {
+            kind: "Image".to_string(),
+            url,
+        });
+        let image = self.banner_url.map(|url| ApImageObject {
+            kind: "Image".to_string(),
+            url,
+        });
+        let profile_url = self.profile_url;
+        let also_known_as: Vec<String> = self.also_known_as.into_iter().collect();
+        let attachment: Vec<ProfileFieldObject> = self
+            .attachment
+            .into_iter()
+            .map(|f| ProfileFieldObject {
+                kind: "PropertyValue".to_string(),
+                name: f.name,
+                value: f.value,
+            })
+            .collect();
+
+        let shared_inbox =
+            Url::parse(&format!("{}/inbox", data.base_url)).expect("base_url is always valid");
+
+        Ok(Person {
+            kind: Default::default(),
+            id: self.ap_id.clone().into(),
+            preferred_username: self.username.clone(),
+            inbox: self.inbox_url.clone(),
+            outbox: self.outbox_url.clone(),
+            followers: self.followers_url.clone(),
+            following: self.following_url.clone(),
+            public_key,
+            name: Some(self.username.clone()),
+            summary: self.bio.clone(),
+            icon,
+            url: profile_url,
+            discoverable: Some(true),
+            manually_approves_followers: true,
+            updated: Some(self.last_refreshed_at),
+            endpoints: Some(Endpoints { shared_inbox }),
+            image,
+            also_known_as,
+            attachment,
+        })
+    }
+
+    async fn verify(
+        json: &Self::Kind,
+        expected_domain: &Url,
+        _data: &Data<Self::DataType>,
+    ) -> Result<(), Self::Error> {
+        verify_domains_match(json.id.inner(), expected_domain)?;
+        Ok(())
+    }
+
+    async fn from_json(json: Self::Kind, data: &Data<Self::DataType>) -> Result<Self, Self::Error> {
+        let shared_inbox_url = json.endpoints.as_ref().map(|e| e.shared_inbox.to_string());
+        let actor = RemoteActor {
+            url: json.id.inner().to_string(),
+            handle: json.preferred_username.clone(),
+            inbox_url: json.inbox.to_string(),
+            shared_inbox_url,
+            display_name: json.name.clone(),
+            avatar_url: json.icon.as_ref().map(|i| i.url.to_string()),
+            outbox_url: Some(json.outbox.to_string()),
+        };
+        data.federation_repo.upsert_remote_actor(actor).await?;
+
+        let url_str = json.id.inner().to_string();
+        let user_id = uuid::Uuid::new_v5(&uuid::Uuid::NAMESPACE_URL, url_str.as_bytes());
+        let ap_id = json.id.inner().clone();
+        let inbox_url = json.inbox.clone();
+        let shared_inbox_url = json
+            .endpoints
+            .as_ref()
+            .and_then(|e| Url::parse(e.shared_inbox.as_str()).ok());
+        let outbox_url = json.outbox.clone();
+        let followers_url = json.followers.clone();
+        let following_url = json.following.clone();
+
+        Ok(DbActor {
+            user_id,
+            username: json.preferred_username.clone(),
+            public_key_pem: json.public_key.public_key_pem,
+            private_key_pem: None,
+            inbox_url,
+            shared_inbox_url,
+            outbox_url,
+            followers_url,
+            following_url,
+            ap_id,
+            last_refreshed_at: Utc::now(),
+            bio: json.summary.clone(),
+            avatar_url: json.icon.as_ref().map(|i| i.url.clone()),
+            banner_url: json.image.as_ref().map(|i| i.url.clone()),
+            also_known_as: json.also_known_as.into_iter().next(),
+            profile_url: json.url.clone(),
+            attachment: json
+                .attachment
+                .iter()
+                .map(|f| crate::user::ApProfileField {
+                    name: f.name.clone(),
+                    value: f.value.clone(),
+                })
+                .collect(),
+        })
+    }
+}
+
+impl Actor for DbActor {
+    fn public_key_pem(&self) -> &str {
+        &self.public_key_pem
+    }
+
+    fn private_key_pem(&self) -> Option<String> {
+        self.private_key_pem.clone()
+    }
+
+    fn inbox(&self) -> Url {
+        self.inbox_url.clone()
+    }
+}
+
+#[cfg(test)]
+#[path = "tests/actors.rs"]
+mod tests;

crates/adapters/activitypub-base/src/ap_ports.rs

@@ -0,0 +1,167 @@
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    models::thought::Thought,
+    value_objects::{ThoughtId, UserId, Username},
+};
+
+/// AP-protocol endpoints for a locally-stored user (local or interned remote).
+#[derive(Debug, Clone)]
+pub struct ActorApUrls {
+    pub ap_id: String,
+    pub inbox_url: String,
+}
+
+/// A local thought ready for AP serialization, with the author's username
+/// pre-joined so the handler can build AP URLs without a second query.
+#[derive(Debug, Clone)]
+pub struct OutboxEntry {
+    pub thought: Thought,
+    pub author_username: Username,
+}
+
+#[async_trait]
+pub trait ActivityPubRepository: Send + Sync {
+    // ── Outbox (local → remote) ──────────────────────────────────────
+
+    /// All public local thoughts for this actor. Used for outbox totals
+    /// and full-collection delivery.
+    async fn outbox_entries_for_actor(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<OutboxEntry>, DomainError>;
+
+    /// Cursor page of public local thoughts, newest-first, before `before`.
+    /// Used for OrderedCollectionPage responses.
+    async fn outbox_page_for_actor(
+        &self,
+        user_id: &UserId,
+        before: Option<chrono::DateTime<chrono::Utc>>,
+        limit: usize,
+    ) -> Result<Vec<OutboxEntry>, DomainError>;
+
+    // ── Remote actor resolution ──────────────────────────────────────
+
+    /// Find the local UserId for a remote actor by its AP URL.
+    async fn find_remote_actor_id(&self, actor_ap_url: &str)
+        -> Result<Option<UserId>, DomainError>;
+
+    /// Ensure a remote actor placeholder exists; create one if absent.
+    /// Idempotent — safe to call multiple times with the same URL.
+    async fn intern_remote_actor(&self, actor_ap_url: &str) -> Result<UserId, DomainError>;
+
+    /// Update display_name and avatar_url for an already-interned remote actor.
+    async fn update_remote_actor_display(
+        &self,
+        user_id: &UserId,
+        display_name: Option<&str>,
+        avatar_url: Option<&str>,
+    ) -> Result<(), DomainError>;
+
+    // ── Inbox processing (remote → local) ───────────────────────────
+
+    /// Persist an incoming remote Note. Idempotent on ap_id.
+    #[allow(clippy::too_many_arguments)]
+    async fn accept_note(
+        &self,
+        ap_id: &str,
+        author_id: &UserId,
+        content: &str,
+        published: chrono::DateTime<chrono::Utc>,
+        sensitive: bool,
+        content_warning: Option<String>,
+        visibility: &str,
+        in_reply_to: Option<&str>,
+    ) -> Result<ThoughtId, DomainError>;
+
+    /// Apply an Update to a previously accepted remote Note.
+    async fn apply_note_update(&self, ap_id: &str, new_content: &str) -> Result<(), DomainError>;
+
+    /// Remove a specific remote Note (Delete activity). Only touches
+    /// remotely-originated thoughts.
+    async fn retract_note(&self, ap_id: &str) -> Result<(), DomainError>;
+
+    /// Remove all Notes from a remote actor (actor-level Delete/Tombstone).
+    async fn retract_actor_notes(&self, actor_ap_url: &str) -> Result<(), DomainError>;
+
+    // ── Node-level stats ─────────────────────────────────────────────
+
+    /// Total locally-authored thought count for NodeInfo responses.
+    async fn count_local_notes(&self) -> Result<u64, DomainError>;
+
+    /// Return the ActivityPub object URL for a thought, if one is stored.
+    /// Returns None for local thoughts (caller constructs URL from base_url + thought_id).
+    async fn get_thought_ap_id(
+        &self,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<String>, DomainError>;
+
+    /// Return the AP actor URL and inbox URL for a user, if stored.
+    /// Returns None for users that have not been federated.
+    async fn get_actor_ap_urls(&self, user_id: &UserId)
+        -> Result<Option<ActorApUrls>, DomainError>;
+}
+
+#[async_trait]
+pub trait OutboundFederationPort: Send + Sync {
+    /// Fan out a new local Note to all accepted followers.
+    async fn broadcast_create(
+        &self,
+        author_user_id: &UserId,
+        thought: &Thought,
+        author_username: &str,
+        in_reply_to_url: Option<&str>,
+    ) -> Result<(), DomainError>;
+
+    /// Fan out a Delete tombstone for a now-deleted local Note.
+    /// `thought_ap_id` is pre-constructed by the caller because the thought
+    /// has already been deleted from the DB when this fires.
+    async fn broadcast_delete(
+        &self,
+        author_user_id: &UserId,
+        thought_ap_id: &str,
+    ) -> Result<(), DomainError>;
+
+    /// Fan out an Update(Note) for an edited local thought.
+    async fn broadcast_update(
+        &self,
+        author_user_id: &UserId,
+        thought: &Thought,
+        author_username: &str,
+        in_reply_to_url: Option<&str>,
+    ) -> Result<(), DomainError>;
+
+    /// Fan out an Announce(object_ap_id) for a boost.
+    async fn broadcast_announce(
+        &self,
+        booster_user_id: &UserId,
+        object_ap_id: &str,
+    ) -> Result<(), DomainError>;
+
+    /// Fan out an Undo(Announce) to followers when a boost is removed.
+    async fn broadcast_undo_announce(
+        &self,
+        booster_user_id: &UserId,
+        object_ap_id: &str,
+    ) -> Result<(), DomainError>;
+
+    /// Send a Like activity to a remote thought author's inbox.
+    /// Only called when a LOCAL user likes a REMOTE thought (one with an ap_id).
+    async fn broadcast_like(
+        &self,
+        liker_user_id: &UserId,
+        object_ap_id: &str,
+        author_inbox_url: &str,
+    ) -> Result<(), DomainError>;
+
+    /// Send Undo(Like) to a remote thought author's inbox.
+    async fn broadcast_undo_like(
+        &self,
+        liker_user_id: &UserId,
+        object_ap_id: &str,
+        author_inbox_url: &str,
+    ) -> Result<(), DomainError>;
+
+    /// Fan out an Update(Actor) to all accepted followers after a profile change.
+    async fn broadcast_actor_update(&self, user_id: &UserId) -> Result<(), DomainError>;
+}

crates/adapters/activitypub-base/src/content.rs

@@ -0,0 +1,68 @@
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use url::Url;
+
+#[async_trait]
+pub trait ApObjectHandler: Send + Sync {
+    /// Returns (ap_id, serialized object) for all local content owned by this user.
+    /// Used by outbox (count) and backfill (delivery). Must only return locally-authored content.
+    async fn get_local_objects_for_user(
+        &self,
+        user_id: uuid::Uuid,
+    ) -> anyhow::Result<Vec<(Url, serde_json::Value)>>;
+
+    /// Returns up to `limit` objects ordered newest-first, published before `before`.
+    /// Returns (ap_id, object_json, published_at).
+    async fn get_local_objects_page(
+        &self,
+        user_id: uuid::Uuid,
+        before: Option<DateTime<Utc>>,
+        limit: usize,
+    ) -> anyhow::Result<Vec<(Url, serde_json::Value, DateTime<Utc>)>>;
+
+    /// Incoming Create activity — persist remote content.
+    async fn on_create(
+        &self,
+        ap_id: &Url,
+        actor_url: &Url,
+        object: serde_json::Value,
+    ) -> anyhow::Result<()>;
+
+    /// Incoming Update activity — update existing remote content.
+    async fn on_update(
+        &self,
+        ap_id: &Url,
+        actor_url: &Url,
+        object: serde_json::Value,
+    ) -> anyhow::Result<()>;
+
+    /// Incoming Delete activity — remove specific remote content.
+    async fn on_delete(&self, ap_id: &Url, actor_url: &Url) -> anyhow::Result<()>;
+
+    /// Actor unfollowed/was removed — clean up all their remote content.
+    async fn on_actor_removed(&self, actor_url: &Url) -> anyhow::Result<()>;
+
+    /// Called when a remote actor likes a local thought.
+    /// `object_url` is the AP URL of the liked note (e.g. `{base}/thoughts/{uuid}`).
+    /// `actor_url` is the AP URL of the remote actor who sent the Like.
+    async fn on_like(&self, object_url: &Url, actor_url: &Url) -> anyhow::Result<()>;
+
+    /// Called when a remote actor boosts (Announce) a local thought.
+    /// `object_url` is the AP URL of the announced note.
+    /// `actor_url` is the AP URL of the remote actor who sent the Announce.
+    async fn on_announce_received(&self, object_url: &Url, actor_url: &Url) -> anyhow::Result<()>;
+
+    /// Called when a remote actor removes a Like from a local thought.
+    async fn on_unlike(&self, object_url: &Url, actor_url: &Url) -> anyhow::Result<()>;
+
+    /// Called when an inbound Note tags a local user with a Mention.
+    async fn on_mention(
+        &self,
+        thought_ap_id: &Url,
+        mentioned_user_uuid: uuid::Uuid,
+        actor_url: &Url,
+    ) -> anyhow::Result<()>;
+
+    /// Total number of locally-authored posts across all users.
+    async fn count_local_posts(&self) -> anyhow::Result<u64>;
+}

crates/adapters/activitypub-base/src/data.rs

@@ -0,0 +1,49 @@
+use std::sync::Arc;
+
+use crate::content::ApObjectHandler;
+use crate::repository::FederationRepository;
+use crate::user::ApUserRepository;
+use domain::ports::EventPublisher;
+
+#[derive(Clone)]
+pub struct FederationData {
+    pub(crate) federation_repo: Arc<dyn FederationRepository>,
+    pub(crate) user_repo: Arc<dyn ApUserRepository>,
+    pub(crate) object_handler: Arc<dyn ApObjectHandler>,
+    pub(crate) base_url: String,
+    pub(crate) domain: String,
+    pub(crate) allow_registration: bool,
+    pub(crate) software_name: String,
+    #[allow(dead_code)]
+    pub(crate) event_publisher: Option<Arc<dyn EventPublisher>>,
+}
+
+impl FederationData {
+    pub fn new(
+        federation_repo: Arc<dyn FederationRepository>,
+        user_repo: Arc<dyn ApUserRepository>,
+        object_handler: Arc<dyn ApObjectHandler>,
+        base_url: String,
+        allow_registration: bool,
+        software_name: String,
+        event_publisher: Option<Arc<dyn EventPublisher>>,
+    ) -> Self {
+        let domain = base_url
+            .trim_start_matches("https://")
+            .trim_start_matches("http://")
+            .split('/')
+            .next()
+            .unwrap_or("")
+            .to_string();
+        Self {
+            federation_repo,
+            user_repo,
+            object_handler,
+            base_url,
+            domain,
+            allow_registration,
+            software_name,
+            event_publisher,
+        }
+    }
+}

crates/adapters/activitypub-base/src/error.rs

@@ -0,0 +1,48 @@
+use std::fmt::{Display, Formatter};
+
+use axum::http::StatusCode;
+
+#[derive(Debug)]
+pub struct Error(pub(crate) anyhow::Error, pub(crate) StatusCode);
+
+impl Error {
+    pub fn not_found(e: impl Into<anyhow::Error>) -> Self {
+        Self(e.into(), StatusCode::NOT_FOUND)
+    }
+
+    pub fn bad_request(e: impl Into<anyhow::Error>) -> Self {
+        Self(e.into(), StatusCode::BAD_REQUEST)
+    }
+}
+
+impl Display for Error {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(&self.0, f)
+    }
+}
+
+impl<T> From<T> for Error
+where
+    T: Into<anyhow::Error>,
+{
+    fn from(t: T) -> Self {
+        Error(t.into(), StatusCode::INTERNAL_SERVER_ERROR)
+    }
+}
+
+impl axum::response::IntoResponse for Error {
+    fn into_response(self) -> axum::response::Response {
+        let status = self.1;
+        if status.is_server_error() {
+            tracing::error!(error = %self.0, status = status.as_u16(), "federation error");
+        } else {
+            tracing::debug!(error = %self.0, status = status.as_u16(), "federation response");
+        }
+        let body = if status.is_server_error() {
+            "internal server error".to_string()
+        } else {
+            self.0.to_string()
+        };
+        (status, body).into_response()
+    }
+}

crates/adapters/activitypub-base/src/federation.rs

@@ -0,0 +1,49 @@
+use activitypub_federation::config::{Data, FederationConfig, FederationMiddleware, UrlVerifier};
+use activitypub_federation::error::Error as FedError;
+use url::Url;
+
+use crate::data::FederationData;
+
+#[derive(Clone)]
+struct PermissiveVerifier;
+
+#[async_trait::async_trait]
+impl UrlVerifier for PermissiveVerifier {
+    async fn verify(&self, _url: &Url) -> Result<(), FedError> {
+        Ok(())
+    }
+}
+
+#[derive(Clone)]
+pub struct ApFederationConfig(pub FederationConfig<FederationData>);
+
+impl ApFederationConfig {
+    pub async fn new(data: FederationData, debug: bool) -> anyhow::Result<Self> {
+        let config = if debug {
+            FederationConfig::builder()
+                .domain(&data.domain)
+                .app_data(data)
+                .debug(true)
+                .http_signature_compat(true)
+                .url_verifier(Box::new(PermissiveVerifier))
+                .build()
+                .await?
+        } else {
+            FederationConfig::builder()
+                .domain(&data.domain)
+                .app_data(data)
+                .debug(false)
+                .build()
+                .await?
+        };
+        Ok(Self(config))
+    }
+
+    pub fn to_request_data(&self) -> Data<FederationData> {
+        self.0.to_request_data()
+    }
+
+    pub fn middleware(&self) -> FederationMiddleware<FederationData> {
+        FederationMiddleware::new(self.0.clone())
+    }
+}

crates/adapters/activitypub-base/src/followers_handler.rs

@@ -0,0 +1,105 @@
+use activitypub_federation::{axum::json::FederationJson, config::Data};
+use axum::extract::{Path, Query};
+use serde::Deserialize;
+use serde_json::json;
+
+use crate::data::FederationData;
+use crate::error::Error;
+use crate::urls::AP_PAGE_SIZE;
+
+#[derive(Deserialize)]
+pub struct PageQuery {
+    page: Option<u32>,
+}
+
+async fn collection_handler(
+    user_id_str: &str,
+    query: PageQuery,
+    data: Data<FederationData>,
+    collection_type: &str,
+) -> Result<FederationJson<serde_json::Value>, Error> {
+    let user_id = uuid::Uuid::parse_str(user_id_str)
+        .map_err(|_| Error::bad_request(anyhow::anyhow!("invalid user id")))?;
+
+    data.user_repo
+        .find_by_id(user_id)
+        .await
+        .map_err(Error::from)?
+        .ok_or_else(|| Error::not_found(anyhow::anyhow!("user not found")))?;
+
+    let collection_id = format!(
+        "{}/users/{}/{}",
+        data.base_url, user_id_str, collection_type
+    );
+
+    let total = match collection_type {
+        "followers" => data.federation_repo.count_followers(user_id).await,
+        _ => data.federation_repo.count_following(user_id).await,
+    }
+    .map_err(Error::from)?;
+
+    if let Some(page) = query.page {
+        let page = page.max(1);
+        let offset = (page.saturating_sub(1) as usize) * AP_PAGE_SIZE;
+
+        let items: Vec<String> = match collection_type {
+            "followers" => data
+                .federation_repo
+                .get_followers_page(user_id, offset as u32, AP_PAGE_SIZE)
+                .await
+                .map_err(Error::from)?
+                .into_iter()
+                .map(|f| f.actor.url)
+                .collect(),
+            _ => data
+                .federation_repo
+                .get_following_page(user_id, offset as u32, AP_PAGE_SIZE)
+                .await
+                .map_err(Error::from)?
+                .into_iter()
+                .map(|a| a.url)
+                .collect(),
+        };
+
+        let has_next = offset + items.len() < total;
+
+        let mut obj = json!({
+            "@context": crate::urls::AP_CONTEXT,
+            "type": "OrderedCollectionPage",
+            "id": format!("{}?page={}", collection_id, page),
+            "partOf": collection_id,
+            "totalItems": total,
+            "orderedItems": items,
+        });
+
+        if has_next {
+            obj["next"] = json!(format!("{}?page={}", collection_id, page + 1));
+        }
+
+        Ok(FederationJson(obj))
+    } else {
+        Ok(FederationJson(json!({
+            "@context": crate::urls::AP_CONTEXT,
+            "type": "OrderedCollection",
+            "id": collection_id,
+            "totalItems": total,
+            "first": format!("{}?page=1", collection_id),
+        })))
+    }
+}
+
+pub async fn followers_handler(
+    Path(user_id_str): Path<String>,
+    Query(query): Query<PageQuery>,
+    data: Data<FederationData>,
+) -> Result<FederationJson<serde_json::Value>, Error> {
+    collection_handler(&user_id_str, query, data, "followers").await
+}
+
+pub async fn following_handler(
+    Path(user_id_str): Path<String>,
+    Query(query): Query<PageQuery>,
+    data: Data<FederationData>,
+) -> Result<FederationJson<serde_json::Value>, Error> {
+    collection_handler(&user_id_str, query, data, "following").await
+}

crates/adapters/activitypub-base/src/inbox.rs

@@ -0,0 +1,18 @@
+use activitypub_federation::{
+    axum::inbox::{ActivityData, receive_activity},
+    config::Data,
+    protocol::context::WithContext,
+};
+
+use crate::activities::InboxActivities;
+use crate::actors::DbActor;
+use crate::data::FederationData;
+use crate::error::Error;
+
+pub async fn inbox_handler(
+    data: Data<FederationData>,
+    activity_data: ActivityData,
+) -> Result<(), Error> {
+    receive_activity::<WithContext<InboxActivities>, DbActor, FederationData>(activity_data, &data)
+        .await
+}

crates/adapters/activitypub-base/src/lib.rs

@@ -0,0 +1,30 @@
+pub mod activities;
+pub mod actor_handler;
+pub mod actors;
+pub mod ap_ports;
+pub mod content;
+pub mod data;
+pub mod error;
+pub mod federation;
+pub mod followers_handler;
+pub mod inbox;
+pub mod nodeinfo;
+pub mod outbox;
+pub mod repository;
+pub mod service;
+pub(crate) mod urls;
+pub use urls::AS_PUBLIC;
+pub mod user;
+pub mod webfinger;
+
+pub use activitypub_federation::kinds::object::NoteType;
+pub use ap_ports::{ActorApUrls, ActivityPubRepository, OutboxEntry, OutboundFederationPort};
+pub use content::ApObjectHandler;
+pub use data::FederationData;
+pub use error::Error;
+pub use federation::ApFederationConfig;
+pub use repository::{
+    BlockedDomain, FederationRepository, Follower, FollowerStatus, FollowingStatus, RemoteActor,
+};
+pub use service::ActivityPubService;
+pub use user::{ApProfileField, ApUser, ApUserRepository};

crates/adapters/activitypub-base/src/nodeinfo.rs

@@ -0,0 +1,82 @@
+use activitypub_federation::config::Data;
+use axum::Json;
+use serde::Serialize;
+
+use crate::data::FederationData;
+use crate::error::Error;
+
+const NODEINFO_2_0_REL: &str = "http://nodeinfo.diaspora.software/ns/schema/2.0";
+
+#[derive(Serialize)]
+pub struct NodeInfoWellKnown {
+    pub links: Vec<NodeInfoLink>,
+}
+
+#[derive(Serialize)]
+pub struct NodeInfoLink {
+    pub rel: String,
+    pub href: String,
+}
+
+#[derive(Serialize)]
+pub struct NodeInfoSoftware {
+    pub name: String,
+    pub version: String,
+}
+
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NodeInfoUsage {
+    pub users: NodeInfoUsers,
+    pub local_posts: u64,
+}
+
+#[derive(Serialize)]
+pub struct NodeInfoUsers {
+    pub total: usize,
+}
+
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NodeInfo {
+    pub version: String,
+    pub software: NodeInfoSoftware,
+    pub protocols: Vec<String>,
+    pub usage: NodeInfoUsage,
+    pub open_registrations: bool,
+}
+
+pub async fn nodeinfo_well_known_handler(
+    data: Data<FederationData>,
+) -> Result<Json<NodeInfoWellKnown>, Error> {
+    let href = format!("{}/nodeinfo/2.0", data.base_url);
+    Ok(Json(NodeInfoWellKnown {
+        links: vec![NodeInfoLink {
+            rel: NODEINFO_2_0_REL.to_string(),
+            href,
+        }],
+    }))
+}
+
+pub async fn nodeinfo_handler(data: Data<FederationData>) -> Result<Json<NodeInfo>, Error> {
+    let user_count = data.user_repo.count_users().await.unwrap_or(0);
+    let local_posts = data.object_handler.count_local_posts().await.unwrap_or(0);
+
+    Ok(Json(NodeInfo {
+        version: "2.0".to_string(),
+        software: NodeInfoSoftware {
+            name: data.software_name.clone(),
+            version: env!("CARGO_PKG_VERSION").to_string(),
+        },
+        protocols: vec!["activitypub".to_string()],
+        usage: NodeInfoUsage {
+            users: NodeInfoUsers { total: user_count },
+            local_posts,
+        },
+        open_registrations: data.allow_registration,
+    }))
+}
+
+#[cfg(test)]
+#[path = "tests/nodeinfo.rs"]
+mod tests;

crates/adapters/activitypub-base/src/outbox.rs

@@ -0,0 +1,138 @@
+use axum::extract::{Path, Query};
+use axum::response::IntoResponse;
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+use activitypub_federation::{
+    config::Data, fetch::object_id::ObjectId, kinds::activity::CreateType,
+    protocol::context::WithContext,
+};
+
+use crate::{activities::CreateActivity, data::FederationData, error::Error, urls::AP_PAGE_SIZE};
+
+#[derive(Deserialize)]
+pub struct OutboxQuery {
+    page: Option<bool>,
+    before: Option<String>,
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct OrderedCollection {
+    #[serde(rename = "@context")]
+    context: String,
+    #[serde(rename = "type")]
+    kind: String,
+    id: String,
+    total_items: u64,
+    first: String,
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct OrderedCollectionPage {
+    #[serde(rename = "@context")]
+    context: String,
+    #[serde(rename = "type")]
+    kind: String,
+    id: String,
+    part_of: String,
+    ordered_items: Vec<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    next: Option<String>,
+}
+
+pub async fn outbox_handler(
+    Path(user_id_str): Path<String>,
+    Query(query): Query<OutboxQuery>,
+    data: Data<FederationData>,
+) -> Result<axum::response::Response, Error> {
+    let uuid = uuid::Uuid::parse_str(&user_id_str)
+        .map_err(|_| Error::bad_request(anyhow::anyhow!("invalid user id")))?;
+
+    data.user_repo
+        .find_by_id(uuid)
+        .await
+        .map_err(Error::from)?
+        .ok_or_else(|| Error::not_found(anyhow::anyhow!("user not found")))?;
+
+    let outbox_url = format!("{}/users/{}/outbox", data.base_url, user_id_str);
+
+    if query.page.unwrap_or(false) {
+        let before: Option<DateTime<Utc>> = query.before.as_deref().and_then(|s| s.parse().ok());
+
+        let items = data
+            .object_handler
+            .get_local_objects_page(uuid, before, AP_PAGE_SIZE)
+            .await
+            .map_err(|e| Error::from(anyhow::anyhow!("{}", e)))?;
+
+        let actor_url: Url = format!("{}/users/{}", data.base_url, user_id_str)
+            .parse()
+            .expect("valid url");
+
+        let has_more = items.len() == AP_PAGE_SIZE;
+        let oldest_ts = items.last().map(|(_, _, ts)| *ts);
+
+        let followers_url = format!("{}/followers", actor_url);
+        let ordered_items: Vec<serde_json::Value> = items
+            .into_iter()
+            .map(|(ap_id, object, _)| {
+                let create_id = Url::parse(&format!("{}/activity", ap_id)).expect("valid url");
+                serde_json::to_value(WithContext::new_default(CreateActivity {
+                    id: create_id,
+                    kind: CreateType::default(),
+                    actor: ObjectId::from(actor_url.clone()),
+                    object,
+                    to: vec![crate::urls::AS_PUBLIC.to_string()],
+                    cc: vec![followers_url.clone()],
+                    bto: vec![],
+                    bcc: vec![],
+                }))
+                .expect("serializable")
+            })
+            .collect();
+
+        let page_id = match &query.before {
+            Some(b) => format!("{}?page=true&before={}", outbox_url, b),
+            None => format!("{}?page=true", outbox_url),
+        };
+
+        let next = if has_more {
+            oldest_ts.map(|ts| {
+                // Use RFC 3339 with Z suffix (no + sign) to avoid percent-encoding
+                let ts_str = ts.format("%Y-%m-%dT%H:%M:%S%.3fZ").to_string();
+                format!("{}?page=true&before={}", outbox_url, ts_str)
+            })
+        } else {
+            None
+        };
+
+        Ok(axum::Json(OrderedCollectionPage {
+            context: crate::urls::AP_CONTEXT.to_string(),
+            kind: "OrderedCollectionPage".to_string(),
+            id: page_id,
+            part_of: outbox_url,
+            ordered_items,
+            next,
+        })
+        .into_response())
+    } else {
+        let total = data
+            .object_handler
+            .get_local_objects_for_user(uuid)
+            .await
+            .map_err(|e| Error::from(anyhow::anyhow!("{}", e)))?
+            .len() as u64;
+
+        Ok(axum::Json(OrderedCollection {
+            context: crate::urls::AP_CONTEXT.to_string(),
+            kind: "OrderedCollection".to_string(),
+            id: outbox_url.clone(),
+            total_items: total,
+            first: format!("{}?page=true", outbox_url),
+        })
+        .into_response())
+    }
+}

crates/adapters/activitypub-base/src/repository.rs

@@ -0,0 +1,134 @@
+use anyhow::Result;
+use async_trait::async_trait;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum FollowerStatus {
+    Pending,
+    Accepted,
+    Rejected,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum FollowingStatus {
+    Pending,
+    Accepted,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct RemoteActor {
+    pub url: String,
+    pub handle: String,
+    pub inbox_url: String,
+    pub shared_inbox_url: Option<String>,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+    pub outbox_url: Option<String>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Follower {
+    pub actor: RemoteActor,
+    pub status: FollowerStatus,
+}
+
+#[derive(Debug, Clone)]
+pub struct BlockedDomain {
+    pub domain: String,
+    pub reason: Option<String>,
+    pub blocked_at: String,
+}
+
+#[async_trait]
+pub trait FederationRepository: Send + Sync {
+    async fn add_follower(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+        status: FollowerStatus,
+        follow_activity_id: &str,
+    ) -> Result<()>;
+    async fn get_follower_follow_activity_id(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<Option<String>>;
+    async fn remove_follower(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<()>;
+    async fn get_followers(&self, local_user_id: uuid::Uuid) -> Result<Vec<Follower>>;
+    async fn get_followers_page(
+        &self,
+        local_user_id: uuid::Uuid,
+        offset: u32,
+        limit: usize,
+    ) -> Result<Vec<Follower>>;
+    async fn count_followers(&self, local_user_id: uuid::Uuid) -> Result<usize>;
+    async fn get_following_page(
+        &self,
+        local_user_id: uuid::Uuid,
+        offset: u32,
+        limit: usize,
+    ) -> Result<Vec<RemoteActor>>;
+    async fn update_follower_status(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+        status: FollowerStatus,
+    ) -> Result<()>;
+    async fn add_following(
+        &self,
+        local_user_id: uuid::Uuid,
+        actor: RemoteActor,
+        follow_activity_id: &str,
+    ) -> Result<()>;
+    async fn get_follow_activity_id(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<Option<String>>;
+    async fn remove_following(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()>;
+    async fn get_following(&self, local_user_id: uuid::Uuid) -> Result<Vec<RemoteActor>>;
+    async fn count_following(&self, local_user_id: uuid::Uuid) -> Result<usize>;
+    async fn upsert_remote_actor(&self, actor: RemoteActor) -> Result<()>;
+    async fn get_remote_actor(&self, actor_url: &str) -> Result<Option<RemoteActor>>;
+    async fn get_local_actor_keypair(
+        &self,
+        user_id: uuid::Uuid,
+    ) -> Result<Option<(String, String)>>;
+    async fn save_local_actor_keypair(
+        &self,
+        user_id: uuid::Uuid,
+        public_key: String,
+        private_key: String,
+    ) -> Result<()>;
+    async fn get_pending_followers(&self, local_user_id: uuid::Uuid) -> Result<Vec<RemoteActor>>;
+    async fn update_following_status(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+        status: FollowingStatus,
+    ) -> Result<()>;
+    async fn get_following_outbox_url(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<Option<String>>;
+    async fn add_announce(
+        &self,
+        activity_id: &str,
+        object_url: &str,
+        actor_url: &str,
+        announced_at: chrono::DateTime<chrono::Utc>,
+    ) -> Result<()>;
+    async fn count_announces(&self, object_url: &str) -> Result<usize>;
+    async fn add_blocked_domain(&self, domain: &str, reason: Option<&str>) -> Result<()>;
+    async fn remove_blocked_domain(&self, domain: &str) -> Result<()>;
+    async fn get_blocked_domains(&self) -> Result<Vec<BlockedDomain>>;
+    async fn is_domain_blocked(&self, domain: &str) -> Result<bool>;
+    async fn add_blocked_actor(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()>;
+    async fn remove_blocked_actor(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()>;
+    async fn get_blocked_actors(&self, local_user_id: uuid::Uuid) -> Result<Vec<String>>;
+    async fn is_actor_blocked(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<bool>;
+}

crates/adapters/activitypub-base/src/tests/actors.rs

@@ -0,0 +1,49 @@
+use super::*;
+
+#[test]
+fn person_serializes_with_enriched_fields() {
+    let person = Person {
+        kind: Default::default(),
+        id: "https://example.com/users/1"
+            .parse::<url::Url>()
+            .unwrap()
+            .into(),
+        preferred_username: "alice".to_string(),
+        inbox: "https://example.com/users/1/inbox".parse().unwrap(),
+        outbox: "https://example.com/users/1/outbox".parse().unwrap(),
+        followers: "https://example.com/users/1/followers".parse().unwrap(),
+        following: "https://example.com/users/1/following".parse().unwrap(),
+        public_key: PublicKey {
+            id: "https://example.com/users/1#main-key".to_string(),
+            owner: "https://example.com/users/1".parse().unwrap(),
+            public_key_pem: "pem".to_string(),
+        },
+        name: Some("Alice".to_string()),
+        summary: Some("Bio text".to_string()),
+        icon: Some(ApImageObject {
+            kind: "Image".to_string(),
+            url: "https://example.com/images/avatars/1".parse().unwrap(),
+        }),
+        url: Some("https://example.com/u/alice".parse().unwrap()),
+        discoverable: Some(true),
+        manually_approves_followers: true,
+        updated: Some(Utc::now()),
+        endpoints: Some(Endpoints {
+            shared_inbox: "https://example.com/inbox".parse().unwrap(),
+        }),
+        image: None,
+        also_known_as: vec![],
+        attachment: vec![],
+    };
+    let json = serde_json::to_value(&person).unwrap();
+    assert_eq!(json["discoverable"], true);
+    assert_eq!(json["summary"], "Bio text");
+    assert_eq!(json["icon"]["type"], "Image");
+    assert_eq!(json["manuallyApprovesFollowers"], true);
+    assert!(json.get("updated").is_some());
+    assert!(json.get("endpoints").is_some());
+    assert_eq!(
+        json["endpoints"]["sharedInbox"],
+        "https://example.com/inbox"
+    );
+}

crates/adapters/activitypub-base/src/tests/nodeinfo.rs

@@ -0,0 +1,40 @@
+use super::*;
+
+#[test]
+fn nodeinfo_well_known_serializes_correctly() {
+    let doc = NodeInfoWellKnown {
+        links: vec![NodeInfoLink {
+            rel: "http://nodeinfo.diaspora.software/ns/schema/2.0".to_string(),
+            href: "https://example.com/nodeinfo/2.0".to_string(),
+        }],
+    };
+    let json = serde_json::to_value(&doc).unwrap();
+    assert_eq!(
+        json["links"][0]["rel"],
+        "http://nodeinfo.diaspora.software/ns/schema/2.0"
+    );
+    assert_eq!(json["links"][0]["href"], "https://example.com/nodeinfo/2.0");
+}
+
+#[test]
+fn nodeinfo_serializes_camel_case() {
+    let doc = NodeInfo {
+        version: "2.0".to_string(),
+        software: NodeInfoSoftware {
+            name: "my-app".to_string(),
+            version: "0.1.0".to_string(),
+        },
+        protocols: vec!["activitypub".to_string()],
+        usage: NodeInfoUsage {
+            users: NodeInfoUsers { total: 3 },
+            local_posts: 42,
+        },
+        open_registrations: false,
+    };
+    let json = serde_json::to_value(&doc).unwrap();
+    assert_eq!(json["version"], "2.0");
+    assert_eq!(json["software"]["name"], "my-app");
+    assert_eq!(json["usage"]["users"]["total"], 3);
+    assert_eq!(json["usage"]["localPosts"], 42);
+    assert_eq!(json["openRegistrations"], false);
+}

crates/adapters/activitypub-base/src/tests/service.rs

@@ -0,0 +1,75 @@
+fn _assert_impl_federation_lookup_port()
+where
+    crate::service::ActivityPubService: domain::ports::FederationLookupPort,
+{
+}
+
+fn _assert_impl_federation_follow_port()
+where
+    crate::service::ActivityPubService: domain::ports::FederationFollowPort,
+{
+}
+
+fn _assert_impl_federation_follow_request_port()
+where
+    crate::service::ActivityPubService: domain::ports::FederationFollowRequestPort,
+{
+}
+
+fn _assert_impl_federation_fetch_port()
+where
+    crate::service::ActivityPubService: domain::ports::FederationFetchPort,
+{
+}
+
+fn _assert_impl_federation_action_port()
+where
+    crate::service::ActivityPubService: domain::ports::FederationActionPort,
+{
+}
+
+use super::*;
+use crate::repository::{Follower, FollowerStatus, RemoteActor};
+
+fn make_follower(inbox: &str, shared: Option<&str>) -> Follower {
+    Follower {
+        actor: RemoteActor {
+            url: format!("https://remote/{}", inbox),
+            handle: "user".to_string(),
+            inbox_url: inbox.to_string(),
+            shared_inbox_url: shared.map(|s| s.to_string()),
+            display_name: None,
+            avatar_url: None,
+            outbox_url: None,
+        },
+        status: FollowerStatus::Accepted,
+    }
+}
+
+#[test]
+fn collect_inboxes_deduplicates_shared() {
+    let followers = vec![
+        make_follower(
+            "https://mastodon.social/users/a/inbox",
+            Some("https://mastodon.social/inbox"),
+        ),
+        make_follower(
+            "https://mastodon.social/users/b/inbox",
+            Some("https://mastodon.social/inbox"),
+        ),
+        make_follower("https://other.instance/users/c/inbox", None),
+    ];
+    let inboxes = collect_inboxes(&followers);
+    assert_eq!(inboxes.len(), 2);
+    let strs: Vec<_> = inboxes.iter().map(|u| u.as_str()).collect();
+    assert!(strs.contains(&"https://mastodon.social/inbox"));
+    assert!(strs.contains(&"https://other.instance/users/c/inbox"));
+}
+
+#[test]
+fn collect_inboxes_falls_back_to_individual_inbox() {
+    let followers = vec![make_follower("https://example.com/users/x/inbox", None)];
+    let inboxes = collect_inboxes(&followers);
+    assert_eq!(inboxes.len(), 1);
+    assert_eq!(inboxes[0].as_str(), "https://example.com/users/x/inbox");
+}

crates/adapters/activitypub-base/src/urls.rs

@@ -0,0 +1,33 @@
+use url::Url;
+
+use crate::error::Error;
+
+pub const AS_PUBLIC: &str = "https://www.w3.org/ns/activitystreams#Public";
+pub const AP_CONTEXT: &str = "https://www.w3.org/ns/activitystreams";
+pub const AP_PAGE_SIZE: usize = 20;
+
+pub fn extract_user_id_from_url(url: &Url) -> Option<uuid::Uuid> {
+    let path = url.path();
+    path.strip_prefix("/users/")
+        .and_then(|s| s.split('/').next())
+        .and_then(|s| uuid::Uuid::parse_str(s).ok())
+}
+
+pub fn activity_url(base_url: &str) -> Result<Url, Error> {
+    Url::parse(&format!("{}/activities/{}", base_url, uuid::Uuid::new_v4()))
+        .map_err(|e| Error::bad_request(anyhow::anyhow!(e)))
+}
+
+pub fn actor_url(base_url: &str, user_id: uuid::Uuid) -> Url {
+    Url::parse(&format!("{}/users/{}", base_url, user_id))
+        .expect("base_url is always a valid URL prefix")
+}
+
+/// Extract the username segment from a /users/:username URL.
+#[allow(dead_code)]
+pub fn extract_username_from_url(url: &Url) -> Option<String> {
+    url.path()
+        .strip_prefix("/users/")
+        .and_then(|s| s.split('/').next())
+        .map(|s| s.to_string())
+}

crates/adapters/activitypub-base/src/user.rs

@@ -0,0 +1,27 @@
+use async_trait::async_trait;
+use url::Url;
+
+#[derive(Debug, Clone)]
+pub struct ApProfileField {
+    pub name: String,
+    pub value: String,
+}
+
+#[derive(Debug, Clone)]
+pub struct ApUser {
+    pub id: uuid::Uuid,
+    pub username: String,
+    pub bio: Option<String>,
+    pub avatar_url: Option<Url>,
+    pub banner_url: Option<Url>,
+    pub also_known_as: Option<String>,
+    pub profile_url: Option<Url>,
+    pub attachment: Vec<ApProfileField>,
+}
+
+#[async_trait]
+pub trait ApUserRepository: Send + Sync {
+    async fn find_by_id(&self, id: uuid::Uuid) -> anyhow::Result<Option<ApUser>>;
+    async fn find_by_username(&self, username: &str) -> anyhow::Result<Option<ApUser>>;
+    async fn count_users(&self) -> anyhow::Result<usize>;
+}

crates/adapters/activitypub-base/src/webfinger.rs

@@ -0,0 +1,38 @@
+use activitypub_federation::{
+    config::Data,
+    fetch::webfinger::{Webfinger, build_webfinger_response, extract_webfinger_name},
+};
+use axum::{
+    extract::Query,
+    http::header,
+    response::{IntoResponse, Response},
+};
+use serde::Deserialize;
+
+use crate::data::FederationData;
+use crate::error::Error;
+
+#[derive(Deserialize)]
+pub struct WebfingerQuery {
+    resource: String,
+}
+
+pub async fn webfinger_handler(
+    Query(query): Query<WebfingerQuery>,
+    data: Data<FederationData>,
+) -> Result<Response, Error> {
+    let name = extract_webfinger_name(&query.resource, &data)?;
+
+    let user = data
+        .user_repo
+        .find_by_username(name)
+        .await
+        .map_err(Error::from)?
+        .ok_or_else(|| Error::not_found(anyhow::anyhow!("user not found")))?;
+
+    let ap_id = crate::urls::actor_url(&data.base_url, user.id);
+
+    let wf: Webfinger = build_webfinger_response(query.resource, ap_id);
+    let body = serde_json::to_string(&wf).map_err(|e| Error::from(anyhow::anyhow!(e)))?;
+    Ok(([(header::CONTENT_TYPE, "application/jrd+json")], body).into_response())
+}

crates/adapters/activitypub/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "activitypub"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+activitypub-base       = { workspace = true }
+domain                 = { workspace = true }
+url                    = { workspace = true }
+serde                  = { workspace = true }
+serde_json             = { workspace = true }
+anyhow                 = { workspace = true }
+chrono                 = { workspace = true }
+uuid                   = { workspace = true }
+async-trait            = { workspace = true }
+tracing                = { workspace = true }

crates/adapters/activitypub/src/handler.rs

@@ -0,0 +1,408 @@
+use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+
+const USERS_PATH_PREFIX: &str = "/users/";
+const THOUGHTS_PATH_PREFIX: &str = "/thoughts/";
+use chrono::{DateTime, Utc};
+use std::sync::Arc;
+use url::Url;
+
+use crate::note::ThoughtNote;
+use crate::urls::ThoughtsUrls;
+use activitypub_base::{ActivityPubRepository, ApObjectHandler};
+use domain::ports::{EventPublisher, TagRepository};
+use domain::value_objects::UserId;
+
+pub struct ThoughtsObjectHandler {
+    repo: Arc<dyn ActivityPubRepository>,
+    urls: ThoughtsUrls,
+    event_publisher: Option<Arc<dyn EventPublisher>>,
+    tag_repo: Arc<dyn TagRepository>,
+}
+
+impl ThoughtsObjectHandler {
+    pub fn new(
+        repo: Arc<dyn ActivityPubRepository>,
+        base_url: &str,
+        event_publisher: Option<Arc<dyn EventPublisher>>,
+        tag_repo: Arc<dyn TagRepository>,
+    ) -> Self {
+        Self {
+            repo,
+            urls: ThoughtsUrls::new(base_url),
+            event_publisher,
+            tag_repo,
+        }
+    }
+}
+
+#[async_trait]
+impl ApObjectHandler for ThoughtsObjectHandler {
+    async fn get_local_objects_for_user(
+        &self,
+        user_id: uuid::Uuid,
+    ) -> Result<Vec<(Url, serde_json::Value)>> {
+        let uid = UserId::from_uuid(user_id);
+        let entries = self
+            .repo
+            .outbox_entries_for_actor(&uid)
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+        entries
+            .into_iter()
+            .map(|e| {
+                let note_url = self.urls.thought_url(e.thought.id.as_uuid());
+                let actor_url = self.urls.user_url(e.author_username.as_str());
+                let followers = self.urls.user_followers(e.author_username.as_str());
+                let in_reply_to = e
+                    .thought
+                    .in_reply_to_id
+                    .map(|id| self.urls.thought_url(id.as_uuid()));
+                let note = ThoughtNote::new_public(
+                    note_url.clone(),
+                    actor_url,
+                    e.thought.content.as_str().to_owned(),
+                    e.thought.created_at,
+                    in_reply_to,
+                    e.thought.sensitive,
+                    e.thought.content_warning,
+                    followers,
+                );
+                Ok((note_url, serde_json::to_value(&note)?))
+            })
+            .collect()
+    }
+
+    async fn get_local_objects_page(
+        &self,
+        user_id: uuid::Uuid,
+        before: Option<DateTime<Utc>>,
+        limit: usize,
+    ) -> Result<Vec<(Url, serde_json::Value, DateTime<Utc>)>> {
+        let uid = UserId::from_uuid(user_id);
+        let entries = self
+            .repo
+            .outbox_page_for_actor(&uid, before, limit)
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+        entries
+            .into_iter()
+            .map(|e| {
+                let created_at = e.thought.created_at;
+                let note_url = self.urls.thought_url(e.thought.id.as_uuid());
+                let actor_url = self.urls.user_url(e.author_username.as_str());
+                let followers = self.urls.user_followers(e.author_username.as_str());
+                let in_reply_to = e
+                    .thought
+                    .in_reply_to_id
+                    .map(|id| self.urls.thought_url(id.as_uuid()));
+                let note = ThoughtNote::new_public(
+                    note_url.clone(),
+                    actor_url,
+                    e.thought.content.as_str().to_owned(),
+                    created_at,
+                    in_reply_to,
+                    e.thought.sensitive,
+                    e.thought.content_warning,
+                    followers,
+                );
+                Ok((note_url, serde_json::to_value(&note)?, created_at))
+            })
+            .collect()
+    }
+
+    async fn on_create(
+        &self,
+        ap_id: &Url,
+        actor_url: &Url,
+        object: serde_json::Value,
+    ) -> Result<()> {
+        let note: ThoughtNote = serde_json::from_value(object)?;
+        let author_id = self
+            .repo
+            .intern_remote_actor(actor_url.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+
+        // Derive visibility from AP addressing conventions.
+        let as_public = "https://www.w3.org/ns/activitystreams#Public";
+        let in_to = note.to.iter().any(|s| s == as_public);
+        let in_cc = note.cc.iter().any(|s| s == as_public);
+        let has_followers = note.to.iter().any(|s| s.ends_with("/followers"))
+            || note.cc.iter().any(|s| s.ends_with("/followers"));
+
+        let visibility = if in_to {
+            "public"
+        } else if in_cc {
+            "unlisted"
+        } else if has_followers {
+            "followers"
+        } else {
+            "direct"
+        };
+
+        let thought_id = self.repo
+            .accept_note(
+                ap_id.as_str(),
+                &author_id,
+                &note.content,
+                note.published,
+                note.sensitive,
+                note.summary,
+                visibility,
+                note.in_reply_to.as_ref().map(|u| u.as_str()),
+            )
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+
+        // Extract and index hashtags from the AP tag array.
+        let hashtag_names: Vec<String> = note
+            .tag
+            .iter()
+            .filter(|t| t.get("type").and_then(|v| v.as_str()) == Some("Hashtag"))
+            .filter_map(|t| t.get("name").and_then(|v| v.as_str()))
+            .map(|name| name.trim_start_matches('#').to_lowercase())
+            .filter(|name| !name.is_empty())
+            .collect();
+
+        for name in hashtag_names {
+            if let Ok(tag) = self.tag_repo.find_or_create(&name).await {
+                let _ = self.tag_repo.attach_to_thought(&thought_id, tag.id).await;
+            }
+        }
+
+        // Fire mention notifications for local @mentions in the note's tag array.
+        let base_url = url::Url::parse(&self.urls.base_url)
+            .ok()
+            .and_then(|u| u.host_str().map(|h| h.to_string()))
+            .unwrap_or_default();
+
+        for tag in &note.tag {
+            if tag.get("type").and_then(|t| t.as_str()) != Some("Mention") {
+                continue;
+            }
+            let href = match tag.get("href").and_then(|h| h.as_str()) {
+                Some(h) => h,
+                None => continue,
+            };
+            let href_url = match url::Url::parse(href) {
+                Ok(u) => u,
+                Err(_) => continue,
+            };
+            if href_url.host_str().unwrap_or("") != base_url {
+                continue;
+            }
+            let user_uuid = href_url
+                .path()
+                .strip_prefix(USERS_PATH_PREFIX)
+                .and_then(|s| s.split('/').next())
+                .and_then(|s| uuid::Uuid::parse_str(s).ok());
+            if let Some(uuid) = user_uuid {
+                self.on_mention(ap_id, uuid, actor_url)
+                    .await
+                    .unwrap_or_else(|e| {
+                        tracing::warn!(error = %e, "failed to process mention notification");
+                    });
+            }
+        }
+
+        Ok(())
+    }
+
+    async fn on_update(
+        &self,
+        ap_id: &Url,
+        _actor_url: &Url,
+        object: serde_json::Value,
+    ) -> Result<()> {
+        let note: ThoughtNote = serde_json::from_value(object)?;
+        self.repo
+            .apply_note_update(ap_id.as_str(), &note.content)
+            .await
+            .map_err(|e| anyhow!("{e}"))
+    }
+
+    async fn on_delete(&self, ap_id: &Url, _actor_url: &Url) -> Result<()> {
+        self.repo
+            .retract_note(ap_id.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))
+    }
+
+    async fn on_actor_removed(&self, actor_url: &Url) -> Result<()> {
+        self.repo
+            .retract_actor_notes(actor_url.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))
+    }
+
+    async fn on_like(&self, object_url: &Url, actor_url: &Url) -> Result<()> {
+        let thought_uuid = object_url
+            .path()
+            .strip_prefix(THOUGHTS_PATH_PREFIX)
+            .and_then(|s| s.split('/').next())
+            .and_then(|s| uuid::Uuid::parse_str(s).ok());
+
+        let thought_uuid = match thought_uuid {
+            Some(u) => u,
+            None => {
+                tracing::debug!(object = %object_url, "on_like: not a local thought URL, skipping");
+                return Ok(());
+            }
+        };
+
+        let actor_user_id = self
+            .repo
+            .find_remote_actor_id(actor_url.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+
+        let actor_user_id = match actor_user_id {
+            Some(id) => id,
+            None => {
+                tracing::debug!(actor = %actor_url, "on_like: remote actor not interned, skipping notification");
+                return Ok(());
+            }
+        };
+
+        if let Some(ep) = &self.event_publisher {
+            let thought_id = domain::value_objects::ThoughtId::from_uuid(thought_uuid);
+            let like_id = domain::value_objects::LikeId::new();
+            ep.publish(&domain::events::DomainEvent::LikeAdded {
+                like_id,
+                user_id: actor_user_id,
+                thought_id,
+            })
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+        }
+
+        Ok(())
+    }
+
+    async fn on_unlike(&self, object_url: &url::Url, actor_url: &url::Url) -> anyhow::Result<()> {
+        let thought_uuid = object_url
+            .path()
+            .strip_prefix(THOUGHTS_PATH_PREFIX)
+            .and_then(|s| s.split('/').next())
+            .and_then(|s| uuid::Uuid::parse_str(s).ok());
+
+        let thought_uuid = match thought_uuid {
+            Some(u) => u,
+            None => {
+                tracing::debug!(object = %object_url, "on_unlike: not a local thought URL, skipping");
+                return Ok(());
+            }
+        };
+
+        let actor_user_id = self
+            .repo
+            .find_remote_actor_id(actor_url.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+
+        let actor_user_id = match actor_user_id {
+            Some(id) => id,
+            None => {
+                tracing::debug!(actor = %actor_url, "on_unlike: remote actor not interned, skipping");
+                return Ok(());
+            }
+        };
+
+        if let Some(ep) = &self.event_publisher {
+            ep.publish(&domain::events::DomainEvent::LikeRemoved {
+                user_id: actor_user_id,
+                thought_id: domain::value_objects::ThoughtId::from_uuid(thought_uuid),
+            })
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+        }
+
+        Ok(())
+    }
+
+    async fn on_mention(
+        &self,
+        thought_ap_id: &url::Url,
+        mentioned_user_uuid: uuid::Uuid,
+        actor_url: &url::Url,
+    ) -> anyhow::Result<()> {
+        let author_user_id = match self
+            .repo
+            .find_remote_actor_id(actor_url.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))?
+        {
+            Some(id) => id,
+            None => return Ok(()),
+        };
+
+        let thought_uuid = thought_ap_id
+            .path()
+            .strip_prefix(THOUGHTS_PATH_PREFIX)
+            .and_then(|s| s.split('/').next())
+            .and_then(|s| uuid::Uuid::parse_str(s).ok());
+
+        let thought_uuid = match thought_uuid {
+            Some(u) => u,
+            None => return Ok(()),
+        };
+
+        if let Some(ep) = &self.event_publisher {
+            ep.publish(&domain::events::DomainEvent::MentionReceived {
+                thought_id: domain::value_objects::ThoughtId::from_uuid(thought_uuid),
+                mentioned_user_id: domain::value_objects::UserId::from_uuid(mentioned_user_uuid),
+                author_user_id,
+            })
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+        }
+
+        Ok(())
+    }
+
+    async fn on_announce_received(&self, object_url: &Url, actor_url: &Url) -> Result<()> {
+        let thought_uuid = object_url
+            .path()
+            .strip_prefix(THOUGHTS_PATH_PREFIX)
+            .and_then(|s| s.split('/').next())
+            .and_then(|s| uuid::Uuid::parse_str(s).ok());
+
+        let thought_uuid = match thought_uuid {
+            Some(u) => u,
+            None => return Ok(()),
+        };
+
+        let actor_user_id = self
+            .repo
+            .find_remote_actor_id(actor_url.as_str())
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+
+        let actor_user_id = match actor_user_id {
+            Some(id) => id,
+            None => return Ok(()),
+        };
+
+        if let Some(ep) = &self.event_publisher {
+            let thought_id = domain::value_objects::ThoughtId::from_uuid(thought_uuid);
+            let boost_id = domain::value_objects::BoostId::new();
+            ep.publish(&domain::events::DomainEvent::BoostAdded {
+                boost_id,
+                user_id: actor_user_id,
+                thought_id,
+            })
+            .await
+            .map_err(|e| anyhow!("{e}"))?;
+        }
+
+        Ok(())
+    }
+
+    async fn count_local_posts(&self) -> Result<u64> {
+        self.repo
+            .count_local_notes()
+            .await
+            .map_err(|e| anyhow!("{e}"))
+    }
+}

crates/adapters/activitypub/src/lib.rs

@@ -0,0 +1,7 @@
+pub mod handler;
+pub mod note;
+pub mod urls;
+
+pub use handler::ThoughtsObjectHandler;
+pub use note::ThoughtNote;
+pub use urls::ThoughtsUrls;

crates/adapters/activitypub/src/note.rs

@@ -0,0 +1,81 @@
+use activitypub_base::NoteType;
+use activitypub_base::AS_PUBLIC;
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+/// AP Note representing a Thought.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ThoughtNote {
+    #[serde(rename = "type")]
+    pub kind: NoteType,
+    pub id: Url,
+    pub url: Url, // Mastodon uses this as the clickable link
+    pub attributed_to: Url,
+    pub content: String,
+    pub published: DateTime<Utc>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub to: Vec<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub cc: Vec<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub in_reply_to: Option<Url>,
+    pub sensitive: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub summary: Option<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty", default)]
+    pub tag: Vec<serde_json::Value>,
+}
+
+impl ThoughtNote {
+    #[allow(clippy::too_many_arguments)]
+    pub fn new_public(
+        id: Url,
+        actor_url: Url,
+        content: String,
+        published: DateTime<Utc>,
+        in_reply_to: Option<Url>,
+        sensitive: bool,
+        summary: Option<String>,
+        followers_url: Url,
+    ) -> Self {
+        Self {
+            kind: Default::default(),
+            url: id.clone(),
+            id,
+            attributed_to: actor_url,
+            content,
+            published,
+            to: vec![AS_PUBLIC.to_string()],
+            cc: vec![followers_url.to_string()],
+            in_reply_to,
+            sensitive,
+            summary,
+            tag: Vec::new(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn note_serializes_with_public_audience() {
+        let note = ThoughtNote::new_public(
+            "https://example.com/thoughts/1".parse().unwrap(),
+            "https://example.com/users/alice".parse().unwrap(),
+            "Hello world".to_string(),
+            chrono::Utc::now(),
+            None,
+            false,
+            None,
+            "https://example.com/users/alice/followers".parse().unwrap(),
+        );
+        let json = serde_json::to_string(&note).unwrap();
+        assert!(json.contains(AS_PUBLIC));
+        assert!(json.contains("Hello world"));
+        assert!(json.contains("\"url\""));
+    }
+}

crates/adapters/activitypub/src/urls.rs

@@ -0,0 +1,57 @@
+use url::Url;
+
+pub struct ThoughtsUrls {
+    pub base_url: String,
+}
+
+impl ThoughtsUrls {
+    pub fn new(base_url: &str) -> Self {
+        Self {
+            base_url: base_url.trim_end_matches('/').to_string(),
+        }
+    }
+
+    pub fn user_url(&self, username: &str) -> Url {
+        Url::parse(&format!("{}/users/{}", self.base_url, username)).expect("valid URL")
+    }
+
+    pub fn thought_url(&self, thought_id: uuid::Uuid) -> Url {
+        Url::parse(&format!("{}/thoughts/{}", self.base_url, thought_id)).expect("valid URL")
+    }
+
+    pub fn user_inbox(&self, username: &str) -> Url {
+        Url::parse(&format!("{}/users/{}/inbox", self.base_url, username)).expect("valid URL")
+    }
+
+    pub fn user_outbox(&self, username: &str) -> Url {
+        Url::parse(&format!("{}/users/{}/outbox", self.base_url, username)).expect("valid URL")
+    }
+
+    pub fn user_followers(&self, username: &str) -> Url {
+        Url::parse(&format!("{}/users/{}/followers", self.base_url, username)).expect("valid URL")
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn user_url_format() {
+        let urls = ThoughtsUrls::new("https://example.com");
+        assert_eq!(
+            urls.user_url("alice").as_str(),
+            "https://example.com/users/alice"
+        );
+    }
+
+    #[test]
+    fn thought_url_format() {
+        let urls = ThoughtsUrls::new("https://example.com");
+        let id = uuid::Uuid::nil();
+        assert!(urls
+            .thought_url(id)
+            .as_str()
+            .starts_with("https://example.com/thoughts/"));
+    }
+}

crates/adapters/auth/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "auth"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+domain       = { workspace = true }
+async-trait  = { workspace = true }
+thiserror    = { workspace = true }
+uuid         = { workspace = true }
+chrono       = { workspace = true }
+tokio        = { workspace = true }
+serde        = { workspace = true }
+jsonwebtoken = "9"
+argon2       = "0.5"
+bcrypt        = "0.15"
+rand          = "0.8"
+sha2          = "0.10"
+hex           = "0.4"

crates/adapters/auth/src/api_key_service.rs

@@ -0,0 +1,89 @@
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    ports::{ApiKeyRepository, ApiKeyService},
+    value_objects::UserId,
+};
+use sha2::{Digest, Sha256};
+use std::sync::Arc;
+
+pub struct ApiKeyServiceImpl {
+    repo: Arc<dyn ApiKeyRepository>,
+}
+
+impl ApiKeyServiceImpl {
+    pub fn new(repo: Arc<dyn ApiKeyRepository>) -> Self {
+        Self { repo }
+    }
+
+    fn hash(raw: &str) -> String {
+        hex::encode(Sha256::digest(raw.as_bytes()))
+    }
+}
+
+#[async_trait]
+impl ApiKeyService for ApiKeyServiceImpl {
+    async fn validate_key(&self, raw_key: &str) -> Result<Option<UserId>, DomainError> {
+        let hash = Self::hash(raw_key);
+        Ok(self.repo.find_by_hash(&hash).await?.map(|k| k.user_id))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use async_trait::async_trait;
+    use chrono::Utc;
+    use domain::{
+        errors::DomainError,
+        models::api_key::ApiKey,
+        ports::ApiKeyRepository,
+        value_objects::{ApiKeyId, UserId},
+    };
+    use std::sync::{Arc, Mutex};
+
+    struct FakeApiKeyRepo(Mutex<Vec<ApiKey>>);
+
+    #[async_trait]
+    impl ApiKeyRepository for FakeApiKeyRepo {
+        async fn save(&self, key: &ApiKey) -> Result<(), DomainError> {
+            self.0.lock().unwrap().push(key.clone());
+            Ok(())
+        }
+        async fn find_by_hash(&self, hash: &str) -> Result<Option<ApiKey>, DomainError> {
+            Ok(self.0.lock().unwrap().iter().find(|k| k.key_hash == hash).cloned())
+        }
+        async fn list_for_user(&self, _uid: &UserId) -> Result<Vec<ApiKey>, DomainError> {
+            Ok(vec![])
+        }
+        async fn delete(&self, _id: &ApiKeyId, _uid: &UserId) -> Result<(), DomainError> {
+            Ok(())
+        }
+    }
+
+    #[tokio::test]
+    async fn validate_known_key_returns_user_id() {
+        let uid = UserId::new();
+        let raw = "super-secret-key";
+        let hash = ApiKeyServiceImpl::hash(raw);
+        let key = ApiKey {
+            id: ApiKeyId::new(),
+            user_id: uid.clone(),
+            key_hash: hash,
+            name: "test".into(),
+            created_at: Utc::now(),
+        };
+        let repo = Arc::new(FakeApiKeyRepo(Mutex::new(vec![key])));
+        let svc = ApiKeyServiceImpl::new(repo);
+        let result = svc.validate_key(raw).await.unwrap();
+        assert_eq!(result.unwrap().as_uuid(), uid.as_uuid());
+    }
+
+    #[tokio::test]
+    async fn validate_unknown_key_returns_none() {
+        let repo = Arc::new(FakeApiKeyRepo(Mutex::new(vec![])));
+        let svc = ApiKeyServiceImpl::new(repo);
+        let result = svc.validate_key("unknown-key").await.unwrap();
+        assert!(result.is_none());
+    }
+}

crates/adapters/auth/src/lib.rs

@@ -0,0 +1,123 @@
+mod api_key_service;
+
+use async_trait::async_trait;
+use chrono::{Duration, Utc};
+use domain::{
+    errors::DomainError,
+    ports::{AuthService, GeneratedToken, PasswordHasher},
+    value_objects::{PasswordHash, UserId},
+};
+use jsonwebtoken::{decode, encode, DecodingKey, EncodingKey, Header, Validation};
+use serde::{Deserialize, Serialize};
+
+pub use api_key_service::ApiKeyServiceImpl;
+
+#[derive(Serialize, Deserialize)]
+struct Claims {
+    sub: String,
+    exp: usize,
+}
+
+pub struct JwtAuthService {
+    secret: String,
+    ttl_seconds: i64,
+}
+
+impl JwtAuthService {
+    pub fn new(secret: String, ttl_seconds: i64) -> Self {
+        Self {
+            secret,
+            ttl_seconds,
+        }
+    }
+}
+
+impl AuthService for JwtAuthService {
+    fn generate_token(&self, user_id: &UserId) -> Result<GeneratedToken, DomainError> {
+        let exp = (Utc::now() + Duration::seconds(self.ttl_seconds)).timestamp() as usize;
+        let claims = Claims {
+            sub: user_id.as_uuid().to_string(),
+            exp,
+        };
+        let token = encode(
+            &Header::default(),
+            &claims,
+            &EncodingKey::from_secret(self.secret.as_bytes()),
+        )
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+        Ok(GeneratedToken {
+            token,
+            user_id: user_id.clone(),
+        })
+    }
+
+    fn validate_token(&self, token: &str) -> Result<UserId, DomainError> {
+        let data = decode::<Claims>(
+            token,
+            &DecodingKey::from_secret(self.secret.as_bytes()),
+            &Validation::default(),
+        )
+        .map_err(|_| DomainError::Unauthorized)?;
+        let uuid =
+            uuid::Uuid::parse_str(&data.claims.sub).map_err(|_| DomainError::Unauthorized)?;
+        Ok(UserId::from_uuid(uuid))
+    }
+}
+
+pub struct Argon2PasswordHasher;
+
+#[async_trait]
+impl PasswordHasher for Argon2PasswordHasher {
+    async fn hash(&self, plain: &str) -> Result<PasswordHash, DomainError> {
+        use argon2::{password_hash::SaltString, Argon2, PasswordHasher as _};
+        use rand::rngs::OsRng;
+        let salt = SaltString::generate(OsRng);
+        let hash = Argon2::default()
+            .hash_password(plain.as_bytes(), &salt)
+            .map_err(|e| DomainError::Internal(e.to_string()))?
+            .to_string();
+        Ok(PasswordHash(hash))
+    }
+
+    async fn verify(&self, plain: &str, hash: &PasswordHash) -> Result<bool, DomainError> {
+        if hash.0.starts_with("$2") {
+            return bcrypt::verify(plain, &hash.0)
+                .map_err(|e| DomainError::Internal(e.to_string()));
+        }
+        use argon2::{password_hash::PasswordHash as ArgonHash, Argon2, PasswordVerifier};
+        let parsed = ArgonHash::new(&hash.0).map_err(|e| DomainError::Internal(e.to_string()))?;
+        Ok(Argon2::default()
+            .verify_password(plain.as_bytes(), &parsed)
+            .is_ok())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::ports::AuthService;
+
+    #[test]
+    fn generate_and_validate_token() {
+        let svc = JwtAuthService::new("a-secret-that-is-at-least-32-bytes!!".into(), 3600);
+        let id = UserId::new();
+        let tok = svc.generate_token(&id).unwrap();
+        let parsed = svc.validate_token(&tok.token).unwrap();
+        assert_eq!(parsed.as_uuid(), id.as_uuid());
+    }
+
+    #[test]
+    fn invalid_token_returns_unauthorized() {
+        let svc = JwtAuthService::new("a-secret-that-is-at-least-32-bytes!!".into(), 3600);
+        let err = svc.validate_token("not.a.token").unwrap_err();
+        assert!(matches!(err, DomainError::Unauthorized));
+    }
+
+    #[tokio::test]
+    async fn hash_and_verify() {
+        let hasher = Argon2PasswordHasher;
+        let hash = hasher.hash("mypassword").await.unwrap();
+        assert!(hasher.verify("mypassword", &hash).await.unwrap());
+        assert!(!hasher.verify("wrongpassword", &hash).await.unwrap());
+    }
+}

crates/adapters/event-payload/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "event-payload"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+serde      = { workspace = true }
+serde_json = { workspace = true }
+domain     = { workspace = true }
+uuid       = { workspace = true }

crates/adapters/event-payload/src/lib.rs

@@ -0,0 +1,446 @@
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    value_objects::{BoostId, LikeId, ThoughtId, UserId},
+};
+use serde::{Deserialize, Serialize};
+
+/// Serializable mirror of domain::events::DomainEvent.
+/// All IDs are Strings (UUID hex) — no domain type dependencies.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(tag = "type", content = "data")]
+pub enum EventPayload {
+    ThoughtCreated {
+        thought_id: String,
+        user_id: String,
+        in_reply_to_id: Option<String>,
+    },
+    ThoughtDeleted {
+        thought_id: String,
+        user_id: String,
+    },
+    ThoughtUpdated {
+        thought_id: String,
+        user_id: String,
+    },
+    LikeAdded {
+        like_id: String,
+        user_id: String,
+        thought_id: String,
+    },
+    LikeRemoved {
+        user_id: String,
+        thought_id: String,
+    },
+    BoostAdded {
+        boost_id: String,
+        user_id: String,
+        thought_id: String,
+    },
+    BoostRemoved {
+        user_id: String,
+        thought_id: String,
+    },
+    FollowRequested {
+        follower_id: String,
+        following_id: String,
+    },
+    FollowAccepted {
+        follower_id: String,
+        following_id: String,
+    },
+    FollowRejected {
+        follower_id: String,
+        following_id: String,
+    },
+    Unfollowed {
+        follower_id: String,
+        following_id: String,
+    },
+    UserBlocked {
+        blocker_id: String,
+        blocked_id: String,
+    },
+    UserUnblocked {
+        blocker_id: String,
+        blocked_id: String,
+    },
+    UserRegistered {
+        user_id: String,
+    },
+    ProfileUpdated {
+        user_id: String,
+    },
+    MentionReceived {
+        thought_id: String,
+        mentioned_user_id: String,
+        author_user_id: String,
+    },
+}
+
+impl EventPayload {
+    /// Returns the NATS subject for this event.
+    pub fn subject(&self) -> &'static str {
+        match self {
+            Self::ThoughtCreated { .. } => "thoughts.created",
+            Self::ThoughtDeleted { .. } => "thoughts.deleted",
+            Self::ThoughtUpdated { .. } => "thoughts.updated",
+            Self::LikeAdded { .. } => "likes.added",
+            Self::LikeRemoved { .. } => "likes.removed",
+            Self::BoostAdded { .. } => "boosts.added",
+            Self::BoostRemoved { .. } => "boosts.removed",
+            Self::FollowRequested { .. } => "follows.requested",
+            Self::FollowAccepted { .. } => "follows.accepted",
+            Self::FollowRejected { .. } => "follows.rejected",
+            Self::Unfollowed { .. } => "follows.removed",
+            Self::UserBlocked { .. } => "users.blocked",
+            Self::UserUnblocked { .. } => "users.unblocked",
+            Self::UserRegistered { .. } => "users.registered",
+            Self::ProfileUpdated { .. } => "users.profile_updated",
+            Self::MentionReceived { .. } => "mentions.received",
+        }
+    }
+}
+
+// ── DomainEvent → EventPayload ─────────────────────────────────────────────
+
+impl From<&DomainEvent> for EventPayload {
+    fn from(e: &DomainEvent) -> Self {
+        match e {
+            DomainEvent::ThoughtCreated {
+                thought_id,
+                user_id,
+                in_reply_to_id,
+            } => Self::ThoughtCreated {
+                thought_id: thought_id.to_string(),
+                user_id: user_id.to_string(),
+                in_reply_to_id: in_reply_to_id.as_ref().map(|x| x.to_string()),
+            },
+            DomainEvent::ThoughtDeleted {
+                thought_id,
+                user_id,
+            } => Self::ThoughtDeleted {
+                thought_id: thought_id.to_string(),
+                user_id: user_id.to_string(),
+            },
+            DomainEvent::ThoughtUpdated {
+                thought_id,
+                user_id,
+            } => Self::ThoughtUpdated {
+                thought_id: thought_id.to_string(),
+                user_id: user_id.to_string(),
+            },
+            DomainEvent::LikeAdded {
+                like_id,
+                user_id,
+                thought_id,
+            } => Self::LikeAdded {
+                like_id: like_id.to_string(),
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
+            },
+            DomainEvent::LikeRemoved {
+                user_id,
+                thought_id,
+            } => Self::LikeRemoved {
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
+            },
+            DomainEvent::BoostAdded {
+                boost_id,
+                user_id,
+                thought_id,
+            } => Self::BoostAdded {
+                boost_id: boost_id.to_string(),
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
+            },
+            DomainEvent::BoostRemoved {
+                user_id,
+                thought_id,
+            } => Self::BoostRemoved {
+                user_id: user_id.to_string(),
+                thought_id: thought_id.to_string(),
+            },
+            DomainEvent::FollowRequested {
+                follower_id,
+                following_id,
+            } => Self::FollowRequested {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
+            },
+            DomainEvent::FollowAccepted {
+                follower_id,
+                following_id,
+            } => Self::FollowAccepted {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
+            },
+            DomainEvent::FollowRejected {
+                follower_id,
+                following_id,
+            } => Self::FollowRejected {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
+            },
+            DomainEvent::Unfollowed {
+                follower_id,
+                following_id,
+            } => Self::Unfollowed {
+                follower_id: follower_id.to_string(),
+                following_id: following_id.to_string(),
+            },
+            DomainEvent::UserBlocked {
+                blocker_id,
+                blocked_id,
+            } => Self::UserBlocked {
+                blocker_id: blocker_id.to_string(),
+                blocked_id: blocked_id.to_string(),
+            },
+            DomainEvent::UserUnblocked {
+                blocker_id,
+                blocked_id,
+            } => Self::UserUnblocked {
+                blocker_id: blocker_id.to_string(),
+                blocked_id: blocked_id.to_string(),
+            },
+            DomainEvent::UserRegistered { user_id } => Self::UserRegistered {
+                user_id: user_id.to_string(),
+            },
+            DomainEvent::ProfileUpdated { user_id } => Self::ProfileUpdated {
+                user_id: user_id.to_string(),
+            },
+            DomainEvent::MentionReceived {
+                thought_id,
+                mentioned_user_id,
+                author_user_id,
+            } => Self::MentionReceived {
+                thought_id: thought_id.to_string(),
+                mentioned_user_id: mentioned_user_id.to_string(),
+                author_user_id: author_user_id.to_string(),
+            },
+        }
+    }
+}
+
+// ── EventPayload → DomainEvent ─────────────────────────────────────────────
+
+fn parse_uuid(s: &str, field: &str) -> Result<uuid::Uuid, DomainError> {
+    uuid::Uuid::parse_str(s)
+        .map_err(|_| DomainError::Internal(format!("invalid uuid for {field}: {s}")))
+}
+
+impl TryFrom<EventPayload> for DomainEvent {
+    type Error = DomainError;
+
+    fn try_from(p: EventPayload) -> Result<Self, DomainError> {
+        Ok(match p {
+            EventPayload::ThoughtCreated {
+                thought_id,
+                user_id,
+                in_reply_to_id,
+            } => DomainEvent::ThoughtCreated {
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+                in_reply_to_id: in_reply_to_id
+                    .map(|s| parse_uuid(&s, "in_reply_to_id").map(ThoughtId::from_uuid))
+                    .transpose()?,
+            },
+            EventPayload::ThoughtDeleted {
+                thought_id,
+                user_id,
+            } => DomainEvent::ThoughtDeleted {
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+            },
+            EventPayload::ThoughtUpdated {
+                thought_id,
+                user_id,
+            } => DomainEvent::ThoughtUpdated {
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+            },
+            EventPayload::LikeAdded {
+                like_id,
+                user_id,
+                thought_id,
+            } => DomainEvent::LikeAdded {
+                like_id: LikeId::from_uuid(parse_uuid(&like_id, "like_id")?),
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+            },
+            EventPayload::LikeRemoved {
+                user_id,
+                thought_id,
+            } => DomainEvent::LikeRemoved {
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+            },
+            EventPayload::BoostAdded {
+                boost_id,
+                user_id,
+                thought_id,
+            } => DomainEvent::BoostAdded {
+                boost_id: BoostId::from_uuid(parse_uuid(&boost_id, "boost_id")?),
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+            },
+            EventPayload::BoostRemoved {
+                user_id,
+                thought_id,
+            } => DomainEvent::BoostRemoved {
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+            },
+            EventPayload::FollowRequested {
+                follower_id,
+                following_id,
+            } => DomainEvent::FollowRequested {
+                follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
+                following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
+            },
+            EventPayload::FollowAccepted {
+                follower_id,
+                following_id,
+            } => DomainEvent::FollowAccepted {
+                follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
+                following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
+            },
+            EventPayload::FollowRejected {
+                follower_id,
+                following_id,
+            } => DomainEvent::FollowRejected {
+                follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
+                following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
+            },
+            EventPayload::Unfollowed {
+                follower_id,
+                following_id,
+            } => DomainEvent::Unfollowed {
+                follower_id: UserId::from_uuid(parse_uuid(&follower_id, "follower_id")?),
+                following_id: UserId::from_uuid(parse_uuid(&following_id, "following_id")?),
+            },
+            EventPayload::UserBlocked {
+                blocker_id,
+                blocked_id,
+            } => DomainEvent::UserBlocked {
+                blocker_id: UserId::from_uuid(parse_uuid(&blocker_id, "blocker_id")?),
+                blocked_id: UserId::from_uuid(parse_uuid(&blocked_id, "blocked_id")?),
+            },
+            EventPayload::UserUnblocked {
+                blocker_id,
+                blocked_id,
+            } => DomainEvent::UserUnblocked {
+                blocker_id: UserId::from_uuid(parse_uuid(&blocker_id, "blocker_id")?),
+                blocked_id: UserId::from_uuid(parse_uuid(&blocked_id, "blocked_id")?),
+            },
+            EventPayload::UserRegistered { user_id } => DomainEvent::UserRegistered {
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+            },
+            EventPayload::ProfileUpdated { user_id } => DomainEvent::ProfileUpdated {
+                user_id: UserId::from_uuid(parse_uuid(&user_id, "user_id")?),
+            },
+            EventPayload::MentionReceived {
+                thought_id,
+                mentioned_user_id,
+                author_user_id,
+            } => DomainEvent::MentionReceived {
+                thought_id: ThoughtId::from_uuid(parse_uuid(&thought_id, "thought_id")?),
+                mentioned_user_id: UserId::from_uuid(parse_uuid(
+                    &mentioned_user_id,
+                    "mentioned_user_id",
+                )?),
+                author_user_id: UserId::from_uuid(parse_uuid(&author_user_id, "author_user_id")?),
+            },
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn thought_created_roundtrip() {
+        let p = EventPayload::ThoughtCreated {
+            thought_id: "abc".into(),
+            user_id: "def".into(),
+            in_reply_to_id: None,
+        };
+        let json = serde_json::to_string(&p).unwrap();
+        let back: EventPayload = serde_json::from_str(&json).unwrap();
+        assert_eq!(back.subject(), "thoughts.created");
+    }
+
+    #[test]
+    fn all_subjects_are_unique() {
+        let samples: &[EventPayload] = &[
+            EventPayload::ThoughtCreated {
+                thought_id: "a".into(),
+                user_id: "b".into(),
+                in_reply_to_id: None,
+            },
+            EventPayload::ThoughtDeleted {
+                thought_id: "a".into(),
+                user_id: "b".into(),
+            },
+            EventPayload::ThoughtUpdated {
+                thought_id: "a".into(),
+                user_id: "b".into(),
+            },
+            EventPayload::LikeAdded {
+                like_id: "a".into(),
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::LikeRemoved {
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::BoostAdded {
+                boost_id: "a".into(),
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::BoostRemoved {
+                user_id: "b".into(),
+                thought_id: "c".into(),
+            },
+            EventPayload::FollowRequested {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::FollowAccepted {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::FollowRejected {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::Unfollowed {
+                follower_id: "a".into(),
+                following_id: "b".into(),
+            },
+            EventPayload::UserBlocked {
+                blocker_id: "a".into(),
+                blocked_id: "b".into(),
+            },
+            EventPayload::UserUnblocked {
+                blocker_id: "a".into(),
+                blocked_id: "b".into(),
+            },
+            EventPayload::UserRegistered {
+                user_id: "a".into(),
+            },
+        ];
+        let mut subjects: Vec<&str> = samples.iter().map(|p| p.subject()).collect();
+        subjects.sort();
+        subjects.dedup();
+        assert_eq!(
+            subjects.len(),
+            samples.len(),
+            "each event must have a unique subject"
+        );
+    }
+}

crates/adapters/event-transport/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "event-transport"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+domain        = { workspace = true }
+event-payload = { workspace = true }
+serde_json    = { workspace = true }
+async-trait   = { workspace = true }
+tracing       = { workspace = true }
+futures       = { workspace = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["full"] }

crates/adapters/event-transport/src/lib.rs

@@ -0,0 +1,236 @@
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    events::{DomainEvent, EventEnvelope},
+    ports::{EventConsumer, EventPublisher},
+};
+use event_payload::EventPayload;
+use futures::stream::BoxStream;
+
+/// Abstraction over any pub/sub transport backend.
+/// Implement this for NATS, Kafka, Redis Streams, etc.
+/// The adapter calls `publish_bytes(subject, bytes)` — subjects come from `EventPayload::subject()`.
+#[async_trait]
+pub trait Transport: Send + Sync {
+    async fn publish_bytes(&self, subject: &str, bytes: &[u8]) -> Result<(), DomainError>;
+}
+
+/// Routes domain events to a transport backend.
+///
+/// Converts: `DomainEvent` → `EventPayload` → JSON bytes → `transport.publish_bytes(subject, bytes)`
+///
+/// To swap transports (e.g. NATS → Kafka), replace the `T` at the composition root.
+pub struct EventPublisherAdapter<T: Transport> {
+    transport: T,
+}
+
+impl<T: Transport> EventPublisherAdapter<T> {
+    pub fn new(transport: T) -> Self {
+        Self { transport }
+    }
+}
+
+#[async_trait]
+impl<T: Transport> EventPublisher for EventPublisherAdapter<T> {
+    async fn publish(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        let payload = EventPayload::from(event);
+        let subject = payload.subject();
+        let bytes =
+            serde_json::to_vec(&payload).map_err(|e| DomainError::Internal(e.to_string()))?;
+        tracing::debug!(subject, "publishing event");
+        self.transport.publish_bytes(subject, &bytes).await
+    }
+}
+
+/// A raw inbound message from a transport backend.
+/// `ack` and `nack` are transport-level acknowledgements (e.g. Kafka offset commit).
+/// For at-most-once transports (basic NATS), both are no-ops.
+pub struct RawMessage {
+    pub subject: String,
+    pub payload: Vec<u8>,
+    pub delivery_count: u64,
+    pub ack: Box<dyn Fn() + Send + Sync>,
+    pub nack: Box<dyn Fn() + Send + Sync>,
+}
+
+/// Abstraction over any subscribe/consume backend.
+pub trait MessageSource: Send + Sync {
+    fn messages(&self) -> BoxStream<'_, Result<RawMessage, DomainError>>;
+}
+
+/// Deserializes raw transport messages into domain `EventEnvelope`s.
+/// Invalid or unknown messages are skipped with a warning — stream continues.
+pub struct EventConsumerAdapter<S: MessageSource> {
+    source: S,
+}
+
+impl<S: MessageSource> EventConsumerAdapter<S> {
+    pub fn new(source: S) -> Self {
+        Self { source }
+    }
+}
+
+impl<S: MessageSource> EventConsumer for EventConsumerAdapter<S> {
+    fn consume(&self) -> BoxStream<'_, Result<EventEnvelope, DomainError>> {
+        use futures::StreamExt;
+        let stream = self.source.messages();
+        Box::pin(stream.filter_map(|result| async move {
+            match result {
+                Err(e) => {
+                    tracing::warn!("transport error: {e}");
+                    None
+                }
+                Ok(msg) => {
+                    let payload = match serde_json::from_slice::<EventPayload>(&msg.payload) {
+                        Ok(p) => p,
+                        Err(e) => {
+                            tracing::warn!("failed to deserialize event payload — acking to prevent orphan: {e}");
+                            (msg.ack)();
+                            return None;
+                        }
+                    };
+                    let event = match DomainEvent::try_from(payload) {
+                        Ok(e) => e,
+                        Err(e) => {
+                            tracing::warn!("unknown or malformed event type — acking to prevent orphan: {e}");
+                            (msg.ack)();
+                            return None;
+                        }
+                    };
+                    Some(Ok(EventEnvelope {
+                        event,
+                        delivery_count: msg.delivery_count,
+                        ack: msg.ack,
+                        nack: msg.nack,
+                    }))
+                }
+            }
+        }))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use async_trait::async_trait;
+    use domain::value_objects::{ThoughtId, UserId};
+    use std::sync::{Arc, Mutex};
+
+    struct SpyTransport {
+        calls: Arc<Mutex<Vec<(String, Vec<u8>)>>>,
+    }
+    impl SpyTransport {
+        fn new() -> (Self, Arc<Mutex<Vec<(String, Vec<u8>)>>>) {
+            let calls = Arc::new(Mutex::new(vec![]));
+            (
+                Self {
+                    calls: calls.clone(),
+                },
+                calls,
+            )
+        }
+    }
+    #[async_trait]
+    impl Transport for SpyTransport {
+        async fn publish_bytes(&self, subject: &str, bytes: &[u8]) -> Result<(), DomainError> {
+            self.calls
+                .lock()
+                .unwrap()
+                .push((subject.to_string(), bytes.to_vec()));
+            Ok(())
+        }
+    }
+
+    #[tokio::test]
+    async fn thought_created_routes_to_correct_subject() {
+        let (spy, calls) = SpyTransport::new();
+        let publisher = EventPublisherAdapter::new(spy);
+        publisher
+            .publish(&DomainEvent::ThoughtCreated {
+                thought_id: ThoughtId::new(),
+                user_id: UserId::new(),
+                in_reply_to_id: None,
+            })
+            .await
+            .unwrap();
+        let calls = calls.lock().unwrap();
+        assert_eq!(calls.len(), 1);
+        assert_eq!(calls[0].0, "thoughts.created");
+    }
+
+    #[tokio::test]
+    async fn serialized_payload_is_valid_json() {
+        let (spy, calls) = SpyTransport::new();
+        let publisher = EventPublisherAdapter::new(spy);
+        publisher
+            .publish(&DomainEvent::UserBlocked {
+                blocker_id: UserId::new(),
+                blocked_id: UserId::new(),
+            })
+            .await
+            .unwrap();
+        let bytes = calls.lock().unwrap()[0].1.clone();
+        let json: serde_json::Value = serde_json::from_slice(&bytes).expect("valid JSON");
+        assert_eq!(json["type"], "UserBlocked");
+    }
+
+    #[tokio::test]
+    async fn consumer_adapter_deserializes_and_yields_event() {
+        use domain::value_objects::ThoughtId;
+        use futures::StreamExt;
+
+        let event = DomainEvent::ThoughtCreated {
+            thought_id: ThoughtId::new(),
+            user_id: UserId::new(),
+            in_reply_to_id: None,
+        };
+        let payload = EventPayload::from(&event);
+        let bytes = serde_json::to_vec(&payload).unwrap();
+
+        struct OneMessageSource {
+            bytes: Vec<u8>,
+        }
+        #[async_trait::async_trait]
+        impl MessageSource for OneMessageSource {
+            fn messages(&self) -> futures::stream::BoxStream<'_, Result<RawMessage, DomainError>> {
+                let msg = RawMessage {
+                    subject: "thoughts.created".to_string(),
+                    payload: self.bytes.clone(),
+                    delivery_count: 1,
+                    ack: Box::new(|| {}),
+                    nack: Box::new(|| {}),
+                };
+                Box::pin(futures::stream::once(async { Ok(msg) }))
+            }
+        }
+
+        let adapter = EventConsumerAdapter::new(OneMessageSource { bytes });
+        let mut stream = adapter.consume();
+        let envelope = stream.next().await.unwrap().unwrap();
+        assert!(matches!(envelope.event, DomainEvent::ThoughtCreated { .. }));
+    }
+
+    #[tokio::test]
+    async fn consumer_adapter_skips_invalid_payloads() {
+        use futures::StreamExt;
+
+        struct BadMessageSource;
+        #[async_trait::async_trait]
+        impl MessageSource for BadMessageSource {
+            fn messages(&self) -> futures::stream::BoxStream<'_, Result<RawMessage, DomainError>> {
+                let msg = RawMessage {
+                    subject: "bad".to_string(),
+                    payload: b"not valid json".to_vec(),
+                    delivery_count: 1,
+                    ack: Box::new(|| {}),
+                    nack: Box::new(|| {}),
+                };
+                Box::pin(futures::stream::once(async { Ok(msg) }))
+            }
+        }
+
+        let adapter = EventConsumerAdapter::new(BadMessageSource);
+        let mut stream = adapter.consume();
+        assert!(stream.next().await.is_none());
+    }
+}

crates/adapters/nats/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "nats"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+domain           = { workspace = true }
+event-payload    = { workspace = true }
+event-transport  = { workspace = true }
+async-nats       = { workspace = true }
+async-stream     = { workspace = true }
+serde_json       = { workspace = true }
+futures          = { workspace = true }
+tokio            = { workspace = true }
+async-trait      = { workspace = true }
+tracing          = { workspace = true }
+uuid             = { workspace = true }

crates/adapters/nats/src/lib.rs

@@ -0,0 +1,285 @@
+use async_nats::jetstream::{self, stream::Config as StreamConfig, AckKind};
+use async_trait::async_trait;
+use domain::errors::DomainError;
+use event_transport::{MessageSource, RawMessage, Transport};
+use futures::stream::BoxStream;
+use std::sync::Arc;
+
+const STREAM_NAME: &str = "THOUGHTS_EVENTS";
+const STREAM_SUBJECT: &str = "thoughts-events.>";
+const CONSUMER_NAME: &str = "worker";
+const MAX_MESSAGES: i64 = 100_000;
+
+/// Maximum NATS delivery attempts before a message is considered exhausted.
+pub const CONSUMER_MAX_DELIVER: i64 = 5;
+/// How long NATS waits for an ack before redelivering.
+const CONSUMER_ACK_WAIT_SECS: u64 = 30;
+/// Timeout for spawned ack/nack async tasks.
+const ACK_TASK_TIMEOUT_SECS: u64 = 5;
+
+fn stream_config() -> StreamConfig {
+    StreamConfig {
+        name: STREAM_NAME.to_string(),
+        subjects: vec![STREAM_SUBJECT.to_string()],
+        max_messages: MAX_MESSAGES,
+        ..Default::default()
+    }
+}
+
+/// Ensure the JetStream stream exists with the current config.
+/// If an incompatible stream exists (e.g. wrong retention policy), deletes and recreates it.
+pub async fn ensure_stream(client: &async_nats::Client) -> Result<(), DomainError> {
+    let js = jetstream::new(client.clone());
+
+    // Happy path: stream exists and config is compatible.
+    if js.update_stream(stream_config()).await.is_ok() {
+        tracing::info!(subject = STREAM_SUBJECT, "JetStream stream updated");
+        return Ok(());
+    }
+
+    // Update failed — retention policy mismatch or other incompatibility.
+    // Delete the old stream and recreate with current config.
+    tracing::warn!(
+        "JetStream stream update failed (incompatible config), deleting '{STREAM_NAME}' and recreating"
+    );
+    let _ = js.delete_stream(STREAM_NAME).await;
+
+    js.create_stream(stream_config())
+        .await
+        .map(|_| ())
+        .map_err(|e| DomainError::Internal(format!("JetStream stream create failed: {e}")))
+}
+
+// ── NatsTransport — JetStream publish ──────────────────────────────────────
+
+pub struct NatsTransport {
+    jetstream: jetstream::Context,
+}
+
+impl NatsTransport {
+    pub fn new(client: async_nats::Client) -> Self {
+        Self {
+            jetstream: jetstream::new(client),
+        }
+    }
+}
+
+#[async_trait]
+impl Transport for NatsTransport {
+    async fn publish_bytes(&self, subject: &str, bytes: &[u8]) -> Result<(), DomainError> {
+        // Prefix all subjects so they land inside the stream's subject filter.
+        let full_subject = format!("thoughts-events.{subject}");
+        self.jetstream
+            .publish(full_subject, bytes.to_vec().into())
+            .await
+            .map_err(|e| DomainError::Internal(e.to_string()))?
+            .await // wait for server ack — confirms message is durably stored
+            .map_err(|e| DomainError::Internal(e.to_string()))?;
+        Ok(())
+    }
+}
+
+// ── NatsMessageSource — JetStream durable push consumer ────────────────────
+
+pub struct NatsMessageSource {
+    jetstream: jetstream::Context,
+}
+
+impl NatsMessageSource {
+    pub fn new(client: async_nats::Client) -> Self {
+        Self {
+            jetstream: jetstream::new(client),
+        }
+    }
+}
+
+impl MessageSource for NatsMessageSource {
+    fn messages(&self) -> BoxStream<'_, Result<RawMessage, DomainError>> {
+        use futures::stream;
+        use tokio::sync::{mpsc, Mutex as TokioMutex};
+
+        let js = self.jetstream.clone();
+        let (tx, rx) = mpsc::channel::<Result<RawMessage, DomainError>>(128);
+
+        // Spawn the consumer loop in the background.
+        // Pull consumer: worker explicitly fetches from NATS rather than NATS pushing.
+        tokio::spawn(async move {
+            let stream = match js.get_stream(STREAM_NAME).await {
+                Ok(s) => s,
+                Err(e) => {
+                    let _ = tx.send(Err(DomainError::Internal(e.to_string()))).await;
+                    return;
+                }
+            };
+
+            // Delete any existing push consumer with this name — can't reuse as pull.
+            // No-op if it doesn't exist or is already a pull consumer.
+            if let Ok(info) = stream.consumer_info(CONSUMER_NAME).await {
+                if info.config.deliver_subject.is_some() {
+                    tracing::info!(
+                        "deleting old push consumer '{CONSUMER_NAME}', replacing with pull"
+                    );
+                    let _ = stream.delete_consumer(CONSUMER_NAME).await;
+                }
+            }
+
+            let consumer = match stream
+                .get_or_create_consumer(
+                    CONSUMER_NAME,
+                    jetstream::consumer::pull::Config {
+                        durable_name: Some(CONSUMER_NAME.to_string()),
+                        deliver_policy: jetstream::consumer::DeliverPolicy::New,
+                        ack_policy: jetstream::consumer::AckPolicy::Explicit,
+                        ack_wait: std::time::Duration::from_secs(CONSUMER_ACK_WAIT_SECS),
+                        max_deliver: CONSUMER_MAX_DELIVER,
+                        // No filter_subject — consume everything from the stream.
+                        // filter_subject matching the stream's own wildcard can be
+                        // inconsistent across NATS server versions.
+                        ..Default::default()
+                    },
+                )
+                .await
+            {
+                Ok(c) => c,
+                Err(e) => {
+                    let _ = tx.send(Err(DomainError::Internal(e.to_string()))).await;
+                    return;
+                }
+            };
+
+            tracing::info!("NATS pull consumer ready");
+
+            loop {
+                // consumer.messages() uses long-poll (no no_wait flag) — NATS holds the
+                // request open and delivers messages as they arrive.
+                // fetch() in async-nats 0.48 defaults to no_wait:true which returns
+                // immediately when the queue is empty, so we avoid it here.
+                let mut messages = match consumer.messages().await {
+                    Ok(m) => m,
+                    Err(e) => {
+                        tracing::error!("NATS messages() failed: {e}");
+                        let _ = tx.send(Err(DomainError::Internal(e.to_string()))).await;
+                        return;
+                    }
+                };
+
+                use futures::StreamExt;
+                while let Some(result) = messages.next().await {
+                    let msg = match result {
+                        Ok(m) => m,
+                        Err(e) => {
+                            tracing::warn!("NATS message error: {e}");
+                            continue;
+                        }
+                    };
+
+                    let subject = msg.subject.to_string();
+                    let payload = msg.payload.to_vec();
+                    let delivery_count = msg
+                        .info()
+                        .map(|info| info.delivered.max(0) as u64)
+                        .unwrap_or(1);
+                    let msg = Arc::new(msg);
+                    let msg_nack = Arc::clone(&msg);
+
+                    let raw = RawMessage {
+                        subject,
+                        payload,
+                        delivery_count,
+                        ack: Box::new(move || {
+                            let m = Arc::clone(&msg);
+                            tokio::spawn(async move {
+                                let result = tokio::time::timeout(
+                                    std::time::Duration::from_secs(ACK_TASK_TIMEOUT_SECS),
+                                    m.ack(),
+                                )
+                                .await;
+                                match result {
+                                    Ok(Ok(())) => {}
+                                    Ok(Err(e)) => tracing::warn!("NATS ack failed: {e}"),
+                                    Err(_) => tracing::warn!(
+                                        "NATS ack timed out after {ACK_TASK_TIMEOUT_SECS}s"
+                                    ),
+                                }
+                            });
+                        }),
+                        nack: Box::new(move || {
+                            let m = Arc::clone(&msg_nack);
+                            tokio::spawn(async move {
+                                let result = tokio::time::timeout(
+                                    std::time::Duration::from_secs(ACK_TASK_TIMEOUT_SECS),
+                                    m.ack_with(AckKind::Nak(None)),
+                                )
+                                .await;
+                                match result {
+                                    Ok(Ok(())) => {}
+                                    Ok(Err(e)) => tracing::warn!("NATS nack failed: {e}"),
+                                    Err(_) => tracing::warn!(
+                                        "NATS nack timed out after {ACK_TASK_TIMEOUT_SECS}s"
+                                    ),
+                                }
+                            });
+                        }),
+                    };
+
+                    if tx.send(Ok(raw)).await.is_err() {
+                        return; // receiver dropped — worker shutting down
+                    }
+                }
+                // messages() stream ended (e.g. fetch timeout) — loop and restart
+            }
+        });
+
+        // Bridge the channel receiver into a BoxStream.
+        let rx = Arc::new(TokioMutex::new(rx));
+        Box::pin(stream::unfold(rx, |rx| async move {
+            let item = rx.lock().await.recv().await?;
+            Some((item, rx))
+        }))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{
+        events::DomainEvent,
+        value_objects::{LikeId, ThoughtId, UserId},
+    };
+    use event_payload::EventPayload;
+
+    #[test]
+    fn payload_from_domain_event_has_correct_subject() {
+        let event = DomainEvent::ThoughtCreated {
+            thought_id: ThoughtId::new(),
+            user_id: UserId::new(),
+            in_reply_to_id: None,
+        };
+        let payload = EventPayload::from(&event);
+        assert_eq!(payload.subject(), "thoughts.created");
+    }
+
+    #[test]
+    fn domain_event_roundtrip_via_payload() {
+        let uid = UserId::new();
+        let tid = ThoughtId::new();
+        let event = DomainEvent::LikeAdded {
+            like_id: LikeId::new(),
+            user_id: uid.clone(),
+            thought_id: tid.clone(),
+        };
+        let payload = EventPayload::from(&event);
+        let back = DomainEvent::try_from(payload).unwrap();
+        if let DomainEvent::LikeAdded {
+            user_id,
+            thought_id,
+            ..
+        } = back
+        {
+            assert_eq!(user_id, uid);
+            assert_eq!(thought_id, tid);
+        } else {
+            panic!("wrong variant");
+        }
+    }
+}

crates/adapters/postgres-federation/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "postgres-federation"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+activitypub-base = { workspace = true }
+sqlx        = { workspace = true }
+uuid        = { workspace = true }
+chrono      = { workspace = true }
+tracing     = { workspace = true }
+async-trait = { workspace = true }
+anyhow      = { workspace = true }
+url         = { workspace = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["full"] }
+sqlx  = { workspace = true, features = ["migrate"] }

crates/adapters/postgres-federation/src/lib.rs

@@ -0,0 +1,574 @@
+use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use sqlx::PgPool;
+
+use activitypub_base::{
+    ApUser, ApUserRepository, BlockedDomain, FederationRepository, Follower, FollowerStatus,
+    FollowingStatus, RemoteActor,
+};
+
+// ── PostgresFederationRepository ─────────────────────────────────────────────
+
+pub struct PostgresFederationRepository {
+    pool: PgPool,
+}
+
+impl PostgresFederationRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+fn status_str(s: &FollowerStatus) -> &'static str {
+    match s {
+        FollowerStatus::Pending => "pending",
+        FollowerStatus::Accepted => "accepted",
+        FollowerStatus::Rejected => "rejected",
+    }
+}
+fn str_status(s: &str) -> FollowerStatus {
+    match s {
+        "accepted" => FollowerStatus::Accepted,
+        "rejected" => FollowerStatus::Rejected,
+        _ => FollowerStatus::Pending,
+    }
+}
+
+fn map_remote_actor(
+    url: String,
+    handle: String,
+    inbox_url: String,
+    shared_inbox_url: Option<String>,
+    display_name: Option<String>,
+    avatar_url: Option<String>,
+    outbox_url: Option<String>,
+) -> RemoteActor {
+    RemoteActor {
+        url,
+        handle,
+        inbox_url,
+        shared_inbox_url,
+        display_name,
+        avatar_url,
+        outbox_url,
+    }
+}
+
+#[async_trait]
+impl FederationRepository for PostgresFederationRepository {
+    async fn add_follower(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+        status: FollowerStatus,
+        follow_activity_id: &str,
+    ) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO federation_followers(local_user_id,remote_actor_url,status,follow_activity_id)
+             VALUES($1,$2,$3,$4)
+             ON CONFLICT(local_user_id,remote_actor_url) DO UPDATE
+             SET status=EXCLUDED.status, follow_activity_id=EXCLUDED.follow_activity_id"
+        )
+        .bind(local_user_id).bind(remote_actor_url).bind(status_str(&status)).bind(follow_activity_id)
+        .execute(&self.pool).await.map_err(|e| anyhow!(e)).map(|_| ())
+    }
+
+    async fn get_follower_follow_activity_id(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<Option<String>> {
+        sqlx::query_scalar::<_, String>(
+            "SELECT follow_activity_id FROM federation_followers WHERE local_user_id=$1 AND remote_actor_url=$2"
+        ).bind(local_user_id).bind(remote_actor_url).fetch_optional(&self.pool).await.map_err(|e| anyhow!(e))
+    }
+
+    async fn remove_follower(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<()> {
+        sqlx::query(
+            "DELETE FROM federation_followers WHERE local_user_id=$1 AND remote_actor_url=$2",
+        )
+        .bind(local_user_id)
+        .bind(remote_actor_url)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))
+        .map(|_| ())
+    }
+
+    async fn get_followers(&self, local_user_id: uuid::Uuid) -> Result<Vec<Follower>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            remote_actor_url: String,
+            status: String,
+            handle: String,
+            inbox_url: String,
+            shared_inbox_url: Option<String>,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            outbox_url: Option<String>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT f.remote_actor_url, f.status, COALESCE(r.handle,'') AS handle,
+             COALESCE(r.inbox_url,'') AS inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url
+             FROM federation_followers f
+             LEFT JOIN remote_actors r ON r.url=f.remote_actor_url
+             WHERE f.local_user_id=$1 AND f.status='accepted'"
+        ).bind(local_user_id).fetch_all(&self.pool).await.map_err(|e| anyhow!(e)).map(|rows| rows.into_iter().map(|r| Follower {
+            actor: map_remote_actor(r.remote_actor_url, r.handle, r.inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url),
+            status: str_status(&r.status),
+        }).collect())
+    }
+
+    async fn get_followers_page(
+        &self,
+        local_user_id: uuid::Uuid,
+        offset: u32,
+        limit: usize,
+    ) -> Result<Vec<Follower>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            remote_actor_url: String,
+            status: String,
+            handle: String,
+            inbox_url: String,
+            shared_inbox_url: Option<String>,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            outbox_url: Option<String>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT f.remote_actor_url, f.status, COALESCE(r.handle,'') AS handle,
+             COALESCE(r.inbox_url,'') AS inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url
+             FROM federation_followers f
+             LEFT JOIN remote_actors r ON r.url=f.remote_actor_url
+             WHERE f.local_user_id=$1 AND f.status='accepted'
+             ORDER BY f.created_at DESC LIMIT $2 OFFSET $3"
+        ).bind(local_user_id).bind(limit as i64).bind(offset as i64).fetch_all(&self.pool).await.map_err(|e| anyhow!(e)).map(|rows| rows.into_iter().map(|r| Follower {
+            actor: map_remote_actor(r.remote_actor_url, r.handle, r.inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url),
+            status: str_status(&r.status),
+        }).collect())
+    }
+
+    async fn count_followers(&self, local_user_id: uuid::Uuid) -> Result<usize> {
+        let n: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM federation_followers WHERE local_user_id=$1 AND status='accepted'"
+        ).bind(local_user_id).fetch_one(&self.pool).await.map_err(|e| anyhow!(e))?;
+        Ok(n as usize)
+    }
+
+    async fn get_pending_followers(&self, local_user_id: uuid::Uuid) -> Result<Vec<RemoteActor>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            remote_actor_url: String,
+            handle: String,
+            inbox_url: String,
+            shared_inbox_url: Option<String>,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            outbox_url: Option<String>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT f.remote_actor_url, COALESCE(r.handle,'') AS handle,
+             COALESCE(r.inbox_url,'') AS inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url
+             FROM federation_followers f
+             LEFT JOIN remote_actors r ON r.url=f.remote_actor_url
+             WHERE f.local_user_id=$1 AND f.status='pending'"
+        ).bind(local_user_id).fetch_all(&self.pool).await.map_err(|e| anyhow!(e)).map(|rows| rows.into_iter().map(|r|
+            map_remote_actor(r.remote_actor_url, r.handle, r.inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url)
+        ).collect())
+    }
+
+    async fn update_follower_status(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+        status: FollowerStatus,
+    ) -> Result<()> {
+        sqlx::query("UPDATE federation_followers SET status=$3 WHERE local_user_id=$1 AND remote_actor_url=$2")
+            .bind(local_user_id).bind(remote_actor_url).bind(status_str(&status))
+            .execute(&self.pool).await.map_err(|e| anyhow!(e)).map(|_| ())
+    }
+
+    async fn add_following(
+        &self,
+        local_user_id: uuid::Uuid,
+        actor: RemoteActor,
+        follow_activity_id: &str,
+    ) -> Result<()> {
+        self.upsert_remote_actor(actor.clone()).await?;
+        sqlx::query(
+            "INSERT INTO federation_following(local_user_id,remote_actor_url,follow_activity_id,outbox_url)
+             VALUES($1,$2,$3,$4)
+             ON CONFLICT(local_user_id,remote_actor_url) DO UPDATE
+             SET follow_activity_id=EXCLUDED.follow_activity_id"
+        )
+        .bind(local_user_id).bind(&actor.url).bind(follow_activity_id).bind(&actor.outbox_url)
+        .execute(&self.pool).await.map_err(|e| anyhow!(e)).map(|_| ())
+    }
+
+    async fn get_follow_activity_id(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<Option<String>> {
+        sqlx::query_scalar::<_, String>(
+            "SELECT follow_activity_id FROM federation_following WHERE local_user_id=$1 AND remote_actor_url=$2"
+        ).bind(local_user_id).bind(remote_actor_url).fetch_optional(&self.pool).await.map_err(|e| anyhow!(e))
+    }
+
+    async fn remove_following(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()> {
+        sqlx::query(
+            "DELETE FROM federation_following WHERE local_user_id=$1 AND remote_actor_url=$2",
+        )
+        .bind(local_user_id)
+        .bind(actor_url)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))
+        .map(|_| ())
+    }
+
+    async fn get_following(&self, local_user_id: uuid::Uuid) -> Result<Vec<RemoteActor>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            remote_actor_url: String,
+            handle: String,
+            inbox_url: String,
+            shared_inbox_url: Option<String>,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            outbox_url: Option<String>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT f.remote_actor_url, COALESCE(r.handle,'') AS handle,
+             COALESCE(r.inbox_url,'') AS inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url
+             FROM federation_following f
+             LEFT JOIN remote_actors r ON r.url=f.remote_actor_url
+             WHERE f.local_user_id=$1"
+        ).bind(local_user_id).fetch_all(&self.pool).await.map_err(|e| anyhow!(e)).map(|rows| rows.into_iter().map(|r|
+            map_remote_actor(r.remote_actor_url, r.handle, r.inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url)
+        ).collect())
+    }
+
+    async fn get_following_page(
+        &self,
+        local_user_id: uuid::Uuid,
+        offset: u32,
+        limit: usize,
+    ) -> Result<Vec<RemoteActor>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            remote_actor_url: String,
+            handle: String,
+            inbox_url: String,
+            shared_inbox_url: Option<String>,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            outbox_url: Option<String>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT f.remote_actor_url, COALESCE(r.handle,'') AS handle,
+             COALESCE(r.inbox_url,'') AS inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url
+             FROM federation_following f
+             LEFT JOIN remote_actors r ON r.url=f.remote_actor_url
+             WHERE f.local_user_id=$1 AND f.status='accepted'
+             ORDER BY f.created_at DESC LIMIT $2 OFFSET $3"
+        ).bind(local_user_id).bind(limit as i64).bind(offset as i64).fetch_all(&self.pool).await.map_err(|e| anyhow!(e)).map(|rows| rows.into_iter().map(|r|
+            map_remote_actor(r.remote_actor_url, r.handle, r.inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url)
+        ).collect())
+    }
+
+    async fn count_following(&self, local_user_id: uuid::Uuid) -> Result<usize> {
+        let n: i64 =
+            sqlx::query_scalar("SELECT COUNT(*) FROM federation_following WHERE local_user_id=$1 AND status='accepted'")
+                .bind(local_user_id)
+                .fetch_one(&self.pool)
+                .await
+                .map_err(|e| anyhow!(e))?;
+        Ok(n as usize)
+    }
+
+    async fn update_following_status(
+        &self,
+        _local_user_id: uuid::Uuid,
+        _remote_actor_url: &str,
+        _status: FollowingStatus,
+    ) -> Result<()> {
+        Ok(())
+    }
+
+    async fn get_following_outbox_url(
+        &self,
+        local_user_id: uuid::Uuid,
+        remote_actor_url: &str,
+    ) -> Result<Option<String>> {
+        sqlx::query_scalar::<_, String>(
+            "SELECT outbox_url FROM federation_following WHERE local_user_id=$1 AND remote_actor_url=$2"
+        ).bind(local_user_id).bind(remote_actor_url).fetch_optional(&self.pool).await.map_err(|e| anyhow!(e))
+    }
+
+    async fn upsert_remote_actor(&self, actor: RemoteActor) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO remote_actors(url,handle,display_name,inbox_url,shared_inbox_url,public_key,avatar_url,outbox_url,last_fetched_at)
+             VALUES($1,$2,$3,$4,$5,'',$6,$7,NOW())
+             ON CONFLICT(url) DO UPDATE SET handle=EXCLUDED.handle,display_name=EXCLUDED.display_name,
+             inbox_url=EXCLUDED.inbox_url,shared_inbox_url=EXCLUDED.shared_inbox_url,
+             avatar_url=EXCLUDED.avatar_url,outbox_url=EXCLUDED.outbox_url,last_fetched_at=NOW()"
+        )
+        .bind(&actor.url).bind(&actor.handle).bind(&actor.display_name)
+        .bind(&actor.inbox_url).bind(&actor.shared_inbox_url)
+        .bind(&actor.avatar_url).bind(&actor.outbox_url)
+        .execute(&self.pool).await.map_err(|e| anyhow!(e)).map(|_| ())
+    }
+
+    async fn get_remote_actor(&self, actor_url: &str) -> Result<Option<RemoteActor>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            url: String,
+            handle: String,
+            inbox_url: String,
+            shared_inbox_url: Option<String>,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            outbox_url: Option<String>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT url,handle,inbox_url,shared_inbox_url,display_name,avatar_url,outbox_url FROM remote_actors WHERE url=$1"
+        ).bind(actor_url).fetch_optional(&self.pool).await.map_err(|e| anyhow!(e)).map(|o| o.map(|r|
+            map_remote_actor(r.url, r.handle, r.inbox_url, r.shared_inbox_url, r.display_name, r.avatar_url, r.outbox_url)
+        ))
+    }
+
+    async fn get_local_actor_keypair(
+        &self,
+        user_id: uuid::Uuid,
+    ) -> Result<Option<(String, String)>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            public_key: Option<String>,
+            private_key: Option<String>,
+        }
+        let row = sqlx::query_as::<_, Row>(
+            "SELECT public_key, private_key FROM users WHERE id=$1 AND local=true",
+        )
+        .bind(user_id)
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))?;
+        Ok(row.and_then(|r| match (r.public_key, r.private_key) {
+            (Some(pub_k), Some(priv_k)) => Some((pub_k, priv_k)),
+            _ => None,
+        }))
+    }
+
+    async fn save_local_actor_keypair(
+        &self,
+        user_id: uuid::Uuid,
+        public_key: String,
+        private_key: String,
+    ) -> Result<()> {
+        sqlx::query("UPDATE users SET public_key=$2, private_key=$3, updated_at=NOW() WHERE id=$1")
+            .bind(user_id)
+            .bind(&public_key)
+            .bind(&private_key)
+            .execute(&self.pool)
+            .await
+            .map_err(|e| anyhow!(e))
+            .map(|_| ())
+    }
+
+    async fn add_announce(
+        &self,
+        activity_id: &str,
+        object_url: &str,
+        actor_url: &str,
+        announced_at: DateTime<Utc>,
+    ) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO federation_announces(activity_id,object_url,actor_url,announced_at)
+             VALUES($1,$2,$3,$4) ON CONFLICT(activity_id) DO NOTHING",
+        )
+        .bind(activity_id)
+        .bind(object_url)
+        .bind(actor_url)
+        .bind(announced_at)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))
+        .map(|_| ())
+    }
+
+    async fn count_announces(&self, object_url: &str) -> Result<usize> {
+        let n: i64 =
+            sqlx::query_scalar("SELECT COUNT(*) FROM federation_announces WHERE object_url=$1")
+                .bind(object_url)
+                .fetch_one(&self.pool)
+                .await
+                .map_err(|e| anyhow!(e))?;
+        Ok(n as usize)
+    }
+
+    async fn add_blocked_domain(&self, domain: &str, reason: Option<&str>) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO federation_blocked_domains(domain,reason) VALUES($1,$2) ON CONFLICT(domain) DO NOTHING"
+        ).bind(domain).bind(reason).execute(&self.pool).await.map_err(|e| anyhow!(e)).map(|_| ())
+    }
+
+    async fn remove_blocked_domain(&self, domain: &str) -> Result<()> {
+        sqlx::query("DELETE FROM federation_blocked_domains WHERE domain=$1")
+            .bind(domain)
+            .execute(&self.pool)
+            .await
+            .map_err(|e| anyhow!(e))
+            .map(|_| ())
+    }
+
+    async fn get_blocked_domains(&self) -> Result<Vec<BlockedDomain>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            domain: String,
+            reason: Option<String>,
+            blocked_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT domain,reason,blocked_at FROM federation_blocked_domains ORDER BY domain",
+        )
+        .fetch_all(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))
+        .map(|rows| {
+            rows.into_iter()
+                .map(|r| BlockedDomain {
+                    domain: r.domain,
+                    reason: r.reason,
+                    blocked_at: r.blocked_at.to_rfc3339(),
+                })
+                .collect()
+        })
+    }
+
+    async fn is_domain_blocked(&self, domain: &str) -> Result<bool> {
+        let n: i64 =
+            sqlx::query_scalar("SELECT COUNT(*) FROM federation_blocked_domains WHERE domain=$1")
+                .bind(domain)
+                .fetch_one(&self.pool)
+                .await
+                .map_err(|e| anyhow!(e))?;
+        Ok(n > 0)
+    }
+
+    async fn add_blocked_actor(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO federation_blocked_actors(local_user_id,actor_url) VALUES($1,$2) ON CONFLICT DO NOTHING"
+        ).bind(local_user_id).bind(actor_url).execute(&self.pool).await.map_err(|e| anyhow!(e)).map(|_| ())
+    }
+
+    async fn remove_blocked_actor(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()> {
+        sqlx::query("DELETE FROM federation_blocked_actors WHERE local_user_id=$1 AND actor_url=$2")
+            .bind(local_user_id)
+            .bind(actor_url)
+            .execute(&self.pool)
+            .await
+            .map_err(|e| anyhow!(e))
+            .map(|_| ())
+    }
+
+    async fn get_blocked_actors(&self, local_user_id: uuid::Uuid) -> Result<Vec<String>> {
+        sqlx::query_scalar::<_, String>(
+            "SELECT actor_url FROM federation_blocked_actors WHERE local_user_id=$1 ORDER BY created_at DESC"
+        ).bind(local_user_id).fetch_all(&self.pool).await.map_err(|e| anyhow!(e))
+    }
+
+    async fn is_actor_blocked(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<bool> {
+        let n: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM federation_blocked_actors WHERE local_user_id=$1 AND actor_url=$2"
+        ).bind(local_user_id).bind(actor_url).fetch_one(&self.pool).await.map_err(|e| anyhow!(e))?;
+        Ok(n > 0)
+    }
+}
+
+// ── PostgresApUserRepository ──────────────────────────────────────────────────
+
+pub struct PostgresApUserRepository {
+    pool: PgPool,
+    base_url: String,
+}
+
+impl PostgresApUserRepository {
+    pub fn new(pool: PgPool, base_url: String) -> Self {
+        Self { pool, base_url }
+    }
+
+    fn row_to_ap_user(
+        &self,
+        id: uuid::Uuid,
+        username: String,
+        bio: Option<String>,
+        avatar_url: Option<String>,
+    ) -> ApUser {
+        let profile_url = url::Url::parse(&format!("{}/users/{}", self.base_url, username)).ok();
+        let avatar_url = avatar_url.and_then(|u| url::Url::parse(&u).ok());
+        ApUser {
+            id,
+            username,
+            bio,
+            avatar_url,
+            banner_url: None,
+            also_known_as: None,
+            profile_url,
+            attachment: vec![],
+        }
+    }
+}
+
+#[async_trait]
+impl ApUserRepository for PostgresApUserRepository {
+    async fn find_by_id(&self, id: uuid::Uuid) -> Result<Option<ApUser>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            username: String,
+            bio: Option<String>,
+            avatar_url: Option<String>,
+        }
+        let row = sqlx::query_as::<_, Row>(
+            "SELECT id,username,bio,avatar_url FROM users WHERE id=$1 AND local=true",
+        )
+        .bind(id)
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))?;
+        Ok(row.map(|r| self.row_to_ap_user(r.id, r.username, r.bio, r.avatar_url)))
+    }
+
+    async fn find_by_username(&self, username: &str) -> Result<Option<ApUser>> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            username: String,
+            bio: Option<String>,
+            avatar_url: Option<String>,
+        }
+        let row = sqlx::query_as::<_, Row>(
+            "SELECT id,username,bio,avatar_url FROM users WHERE username=$1 AND local=true",
+        )
+        .bind(username)
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(|e| anyhow!(e))?;
+        Ok(row.map(|r| self.row_to_ap_user(r.id, r.username, r.bio, r.avatar_url)))
+    }
+
+    async fn count_users(&self) -> Result<usize> {
+        let n: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM users WHERE local=true")
+            .fetch_one(&self.pool)
+            .await
+            .map_err(|e| anyhow!(e))?;
+        Ok(n as usize)
+    }
+}

crates/adapters/postgres-search/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "postgres-search"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+domain      = { workspace = true }
+postgres    = { workspace = true }
+sqlx        = { workspace = true }
+uuid        = { workspace = true }
+chrono      = { workspace = true }
+async-trait = { workspace = true }
+
+[dev-dependencies]
+tokio    = { workspace = true, features = ["full"] }
+sqlx     = { workspace = true, features = ["migrate"] }
+postgres = { workspace = true }

crates/adapters/postgres-search/src/lib.rs

@@ -0,0 +1,372 @@
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{FeedEntry, PageParams, Paginated},
+        thought::{Thought, Visibility},
+        user::User,
+    },
+    ports::SearchPort,
+    value_objects::{Content, Email, PasswordHash, ThoughtId, UserId, Username},
+};
+use postgres::user::{UserRow, USER_SELECT};
+use sqlx::PgPool;
+
+pub struct PgSearchRepository {
+    pool: PgPool,
+}
+impl PgSearchRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[derive(sqlx::FromRow)]
+struct FeedRow {
+    thought_id: uuid::Uuid,
+    t_user_id: uuid::Uuid,
+    content: String,
+    in_reply_to_id: Option<uuid::Uuid>,
+    visibility: String,
+    content_warning: Option<String>,
+    sensitive: bool,
+    t_local: bool,
+    thought_created_at: DateTime<Utc>,
+    updated_at: Option<DateTime<Utc>>,
+    author_id: uuid::Uuid,
+    username: String,
+    email: String,
+    password_hash: String,
+    display_name: Option<String>,
+    bio: Option<String>,
+    avatar_url: Option<String>,
+    header_url: Option<String>,
+    custom_css: Option<String>,
+    author_local: bool,
+    author_created_at: DateTime<Utc>,
+    author_updated_at: DateTime<Utc>,
+    like_count: i64,
+    boost_count: i64,
+    reply_count: i64,
+    liked_by_viewer: bool,
+    boosted_by_viewer: bool,
+}
+
+fn feed_select(viewer: Option<uuid::Uuid>) -> String {
+    let viewer_checks = match viewer {
+        Some(uid) => format!(
+            "EXISTS(SELECT 1 FROM likes  WHERE user_id='{uid}' AND thought_id=t.id) AS liked_by_viewer,\n\
+             EXISTS(SELECT 1 FROM boosts WHERE user_id='{uid}' AND thought_id=t.id) AS boosted_by_viewer"
+        ),
+        None => "false AS liked_by_viewer, false AS boosted_by_viewer".to_string(),
+    };
+    format!(
+        "\n    SELECT\n\
+         t.id AS thought_id, t.user_id AS t_user_id, t.content,\n\
+         t.in_reply_to_id,\n\
+         t.visibility, t.content_warning, t.sensitive, t.local AS t_local,\n\
+         t.created_at AS thought_created_at, t.updated_at,\n\
+         u.id AS author_id, u.username, u.email, u.password_hash,\n\
+         u.display_name, u.bio, u.avatar_url, u.header_url, u.custom_css,\n\
+         u.local AS author_local,\n\
+         u.created_at AS author_created_at, u.updated_at AS author_updated_at,\n\
+         (SELECT COUNT(*) FROM likes  l WHERE l.thought_id=t.id) AS like_count,\n\
+         (SELECT COUNT(*) FROM boosts b WHERE b.thought_id=t.id) AS boost_count,\n\
+         (SELECT COUNT(*) FROM thoughts r WHERE r.in_reply_to_id=t.id) AS reply_count,\n\
+         {viewer_checks}\n\
+     FROM thoughts t JOIN users u ON u.id=t.user_id"
+    )
+}
+
+fn row_to_entry(r: FeedRow, viewer: Option<uuid::Uuid>) -> Result<FeedEntry, DomainError> {
+    let thought = Thought {
+        id: ThoughtId::from_uuid(r.thought_id),
+        user_id: UserId::from_uuid(r.t_user_id),
+        content: Content::new_remote(r.content),
+        in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
+        visibility: Visibility::from_db_str(&r.visibility)?,
+        content_warning: r.content_warning,
+        sensitive: r.sensitive,
+        local: r.t_local,
+        created_at: r.thought_created_at,
+        updated_at: r.updated_at,
+    };
+    let author = User {
+        id: UserId::from_uuid(r.author_id),
+        username: Username::from_trusted(r.username),
+        email: Email::from_trusted(r.email),
+        password_hash: PasswordHash(r.password_hash),
+        display_name: r.display_name,
+        bio: r.bio,
+        avatar_url: r.avatar_url,
+        header_url: r.header_url,
+        custom_css: r.custom_css,
+        local: r.author_local,
+        created_at: r.author_created_at,
+        updated_at: r.author_updated_at,
+    };
+    Ok(FeedEntry {
+        thought,
+        author,
+        stats: domain::models::feed::EngagementStats {
+            like_count: r.like_count,
+            boost_count: r.boost_count,
+            reply_count: r.reply_count,
+        },
+        viewer: viewer.map(|_| domain::models::feed::ViewerContext {
+            liked: r.liked_by_viewer,
+            boosted: r.boosted_by_viewer,
+        }),
+    })
+}
+
+#[async_trait]
+impl SearchPort for PgSearchRepository {
+    async fn search_thoughts(
+        &self,
+        query: &str,
+        page: &PageParams,
+        viewer_id: Option<&UserId>,
+    ) -> Result<Paginated<FeedEntry>, DomainError> {
+        let viewer = viewer_id.map(|v| v.as_uuid());
+        let select = feed_select(viewer);
+
+        let total: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM thoughts t
+             WHERE t.content % $1 AND t.visibility='public'",
+        )
+        .bind(query)
+        .fetch_one(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        let sql = format!(
+            "{select}
+             WHERE t.content % $1 AND t.visibility='public'
+             ORDER BY similarity(t.content, $1) DESC
+             LIMIT $2 OFFSET $3"
+        );
+        let rows = sqlx::query_as::<_, FeedRow>(&sql)
+            .bind(query)
+            .bind(page.limit())
+            .bind(page.offset())
+            .fetch_all(&self.pool)
+            .await
+            .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        Ok(Paginated {
+            items: rows
+                .into_iter()
+                .map(|r| row_to_entry(r, viewer))
+                .collect::<Result<Vec<_>, _>>()?,
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+
+    async fn search_users(
+        &self,
+        query: &str,
+        page: &PageParams,
+    ) -> Result<Paginated<User>, DomainError> {
+        let total: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM users u
+             WHERE u.local=true AND (u.username % $1 OR u.display_name % $1)",
+        )
+        .bind(query)
+        .fetch_one(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        let sql = format!(
+            "{USER_SELECT}
+             WHERE local=true AND (username % $1 OR display_name % $1)
+             ORDER BY similarity(username || ' ' || COALESCE(display_name,''), $1) DESC
+             LIMIT $2 OFFSET $3"
+        );
+        let rows = sqlx::query_as::<_, UserRow>(&sql)
+            .bind(query)
+            .bind(page.limit())
+            .bind(page.offset())
+            .fetch_all(&self.pool)
+            .await
+            .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        Ok(Paginated {
+            items: rows.into_iter().map(User::from).collect(),
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{
+        models::{
+            thought::{Thought, Visibility},
+            user::User,
+        },
+        ports::{SearchPort, ThoughtRepository, UserWriter},
+        value_objects::*,
+    };
+
+    async fn seed_thought(pool: &sqlx::PgPool, username: &str, content: &str) -> (User, Thought) {
+        use postgres::{thought::PgThoughtRepository, user::PgUserRepository};
+        let urepo = PgUserRepository::new(pool.clone());
+        let trepo = PgThoughtRepository::new(pool.clone());
+        let u = User::new_local(
+            UserId::new(),
+            Username::new(username).unwrap(),
+            Email::new(format!("{username}@ex.com")).unwrap(),
+            PasswordHash("h".into()),
+        );
+        urepo.save(&u).await.unwrap();
+        let t = Thought::new_local(
+            ThoughtId::new(),
+            u.id.clone(),
+            Content::new_local(content).unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        trepo.save(&t).await.unwrap();
+        (u, t)
+    }
+
+    #[sqlx::test(migrations = "../postgres/migrations")]
+    async fn search_thoughts_finds_by_keyword(pool: sqlx::PgPool) {
+        seed_thought(&pool, "alice", "hello world").await;
+        seed_thought(&pool, "bob", "goodbye universe").await;
+        let repo = PgSearchRepository::new(pool);
+        let result = repo
+            .search_thoughts(
+                "hello world",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+                None,
+            )
+            .await
+            .unwrap();
+        assert_eq!(result.total, 1);
+        assert_eq!(result.items[0].thought.content.as_str(), "hello world");
+    }
+
+    #[sqlx::test(migrations = "../postgres/migrations")]
+    async fn search_users_finds_by_username(pool: sqlx::PgPool) {
+        use postgres::user::PgUserRepository;
+        let urepo = PgUserRepository::new(pool.clone());
+        let alice = User::new_local(
+            UserId::new(),
+            Username::new("alice_search").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        );
+        urepo.save(&alice).await.unwrap();
+        let repo = PgSearchRepository::new(pool);
+        let result = repo
+            .search_users(
+                "alice",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+            )
+            .await
+            .unwrap();
+        assert!(!result.items.is_empty());
+        assert!(result
+            .items
+            .iter()
+            .any(|u| u.username.as_str() == "alice_search"));
+    }
+
+    #[sqlx::test(migrations = "../postgres/migrations")]
+    async fn search_thoughts_returns_empty_for_no_match(pool: sqlx::PgPool) {
+        seed_thought(&pool, "alice", "hello world").await;
+        let repo = PgSearchRepository::new(pool);
+        let result = repo
+            .search_thoughts(
+                "zzzzzzzzz",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+                None,
+            )
+            .await
+            .unwrap();
+        assert_eq!(result.total, 0);
+    }
+
+    #[sqlx::test(migrations = "../postgres/migrations")]
+    async fn search_thoughts_viewer_context(pool: sqlx::PgPool) {
+        use domain::models::social::Like;
+        use domain::ports::{LikeRepository, UserWriter};
+        use domain::value_objects::LikeId;
+        use postgres::{like::PgLikeRepository, user::PgUserRepository};
+
+        let (alice, thought) = seed_thought(&pool, "alice", "hello world").await;
+
+        // alice likes her own thought
+        let like_repo = PgLikeRepository::new(pool.clone());
+        like_repo
+            .save(&Like {
+                id: LikeId::new(),
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+                ap_id: None,
+                created_at: chrono::Utc::now(),
+            })
+            .await
+            .unwrap();
+
+        let repo = PgSearchRepository::new(pool);
+
+        // with viewer — should see liked = true
+        let authed = repo
+            .search_thoughts(
+                "hello",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+                Some(&alice.id),
+            )
+            .await
+            .unwrap();
+        assert_eq!(authed.items.len(), 1);
+        let ctx = authed.items[0]
+            .viewer
+            .as_ref()
+            .expect("viewer context present");
+        assert!(ctx.liked, "alice should see the thought as liked");
+        assert!(!ctx.boosted);
+
+        // without viewer — viewer should be None
+        let anon = repo
+            .search_thoughts(
+                "hello",
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+                None,
+            )
+            .await
+            .unwrap();
+        assert_eq!(anon.items.len(), 1);
+        assert!(
+            anon.items[0].viewer.is_none(),
+            "anonymous request has no viewer context"
+        );
+    }
+}

crates/adapters/postgres/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "postgres"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+domain           = { workspace = true }
+activitypub-base = { workspace = true }
+event-payload    = { workspace = true }
+sqlx             = { workspace = true }
+uuid        = { workspace = true }
+serde_json  = { workspace = true }
+chrono      = { workspace = true }
+async-trait = { workspace = true }
+thiserror   = { workspace = true }
+tracing     = { workspace = true }
+url         = { workspace = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["full"] }
+sqlx  = { workspace = true, features = ["migrate"] }

crates/adapters/postgres/migrations/001_initial_schema.sql

@@ -0,0 +1,55 @@
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";
+
+CREATE TABLE IF NOT EXISTS users (
+    id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    username     VARCHAR(32)  NOT NULL UNIQUE,
+    email        VARCHAR(255) NOT NULL UNIQUE,
+    password_hash TEXT        NOT NULL,
+    display_name VARCHAR(50),
+    bio          VARCHAR(160),
+    avatar_url   TEXT,
+    header_url   TEXT,
+    custom_css   TEXT,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at   TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS thoughts (
+    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id    UUID        NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    content    VARCHAR(128) NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS follows (
+    follower_id  UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    following_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    PRIMARY KEY (follower_id, following_id)
+);
+
+CREATE TABLE IF NOT EXISTS top_friends (
+    user_id   UUID     NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    friend_id UUID     NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    position  SMALLINT NOT NULL,
+    PRIMARY KEY (user_id, friend_id),
+    UNIQUE (user_id, position)
+);
+
+CREATE TABLE IF NOT EXISTS tags (
+    id   SERIAL PRIMARY KEY,
+    name VARCHAR(50) NOT NULL UNIQUE
+);
+
+CREATE TABLE IF NOT EXISTS thought_tags (
+    thought_id UUID    NOT NULL REFERENCES thoughts(id) ON DELETE CASCADE,
+    tag_id     INTEGER NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
+    PRIMARY KEY (thought_id, tag_id)
+);
+
+CREATE TABLE IF NOT EXISTS api_keys (
+    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id    UUID        NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    key_hash   TEXT        NOT NULL UNIQUE,
+    name       VARCHAR(50) NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);

crates/adapters/postgres/migrations/002_federation_columns.sql

@@ -0,0 +1,21 @@
+ALTER TABLE users
+    ADD COLUMN IF NOT EXISTS ap_id        TEXT UNIQUE,
+    ADD COLUMN IF NOT EXISTS inbox_url    TEXT,
+    ADD COLUMN IF NOT EXISTS public_key   TEXT,
+    ADD COLUMN IF NOT EXISTS private_key  TEXT,
+    ADD COLUMN IF NOT EXISTS local        BOOLEAN NOT NULL DEFAULT true;
+
+ALTER TABLE thoughts
+    ADD COLUMN IF NOT EXISTS in_reply_to_id  UUID REFERENCES thoughts(id),
+    ADD COLUMN IF NOT EXISTS in_reply_to_url TEXT,
+    ADD COLUMN IF NOT EXISTS ap_id           TEXT UNIQUE,
+    ADD COLUMN IF NOT EXISTS visibility      TEXT NOT NULL DEFAULT 'public',
+    ADD COLUMN IF NOT EXISTS content_warning TEXT,
+    ADD COLUMN IF NOT EXISTS sensitive       BOOLEAN NOT NULL DEFAULT false,
+    ADD COLUMN IF NOT EXISTS local           BOOLEAN NOT NULL DEFAULT true,
+    ADD COLUMN IF NOT EXISTS updated_at      TIMESTAMPTZ;
+
+ALTER TABLE follows
+    ADD COLUMN IF NOT EXISTS state      TEXT        NOT NULL DEFAULT 'accepted',
+    ADD COLUMN IF NOT EXISTS ap_id      TEXT,
+    ADD COLUMN IF NOT EXISTS created_at TIMESTAMPTZ NOT NULL DEFAULT NOW();

crates/adapters/postgres/migrations/003_new_tables.sql

@@ -0,0 +1,49 @@
+CREATE TABLE IF NOT EXISTS likes (
+    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    thought_id UUID NOT NULL REFERENCES thoughts(id) ON DELETE CASCADE,
+    ap_id      TEXT UNIQUE,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (user_id, thought_id)
+);
+
+CREATE TABLE IF NOT EXISTS boosts (
+    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    thought_id UUID NOT NULL REFERENCES thoughts(id) ON DELETE CASCADE,
+    ap_id      TEXT UNIQUE,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (user_id, thought_id)
+);
+
+CREATE TABLE IF NOT EXISTS blocks (
+    blocker_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    blocked_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (blocker_id, blocked_id)
+);
+
+CREATE TABLE IF NOT EXISTS remote_actors (
+    url              TEXT PRIMARY KEY,
+    handle           TEXT NOT NULL,
+    display_name     TEXT,
+    inbox_url        TEXT NOT NULL,
+    shared_inbox_url TEXT,
+    public_key       TEXT NOT NULL,
+    last_fetched_at  TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS notifications (
+    id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id      UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    type         TEXT NOT NULL,
+    from_user_id UUID REFERENCES users(id) ON DELETE SET NULL,
+    thought_id   UUID REFERENCES thoughts(id) ON DELETE CASCADE,
+    read         BOOLEAN NOT NULL DEFAULT false,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_thoughts_user_id ON thoughts(user_id);
+CREATE INDEX IF NOT EXISTS idx_thoughts_created_at ON thoughts(created_at DESC);
+CREATE INDEX IF NOT EXISTS idx_follows_following_id ON follows(following_id);
+CREATE INDEX IF NOT EXISTS idx_notifications_user_id ON notifications(user_id, read);

crates/adapters/postgres/migrations/004_search_indexes.sql

@@ -0,0 +1,11 @@
+CREATE EXTENSION IF NOT EXISTS pg_trgm;
+
+CREATE INDEX IF NOT EXISTS idx_thoughts_content_trgm
+    ON thoughts USING GIN(content gin_trgm_ops);
+
+CREATE INDEX IF NOT EXISTS idx_users_username_trgm
+    ON users USING GIN(username gin_trgm_ops);
+
+CREATE INDEX IF NOT EXISTS idx_users_display_name_trgm
+    ON users USING GIN(display_name gin_trgm_ops)
+    WHERE display_name IS NOT NULL;

crates/adapters/postgres/migrations/005_federation_tables.sql

@@ -0,0 +1,54 @@
+-- Add avatar_url and outbox_url to remote_actors (FederationRepository::RemoteActor needs them)
+ALTER TABLE remote_actors
+    ADD COLUMN IF NOT EXISTS avatar_url  TEXT,
+    ADD COLUMN IF NOT EXISTS outbox_url  TEXT;
+
+-- Federation followers: remote actors following local users
+CREATE TABLE IF NOT EXISTS federation_followers (
+    id               UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    local_user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    remote_actor_url TEXT NOT NULL,
+    status           TEXT NOT NULL DEFAULT 'pending',
+    follow_activity_id TEXT NOT NULL,
+    created_at       TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (local_user_id, remote_actor_url)
+);
+
+-- Federation following: local users following remote actors
+CREATE TABLE IF NOT EXISTS federation_following (
+    id               UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    local_user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    remote_actor_url TEXT NOT NULL,
+    follow_activity_id TEXT NOT NULL,
+    outbox_url       TEXT,
+    created_at       TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (local_user_id, remote_actor_url)
+);
+
+-- Announces (boosts of remote objects via AP)
+CREATE TABLE IF NOT EXISTS federation_announces (
+    id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    activity_id  TEXT NOT NULL UNIQUE,
+    object_url   TEXT NOT NULL,
+    actor_url    TEXT NOT NULL,
+    announced_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+-- Blocked domains (instance-level)
+CREATE TABLE IF NOT EXISTS federation_blocked_domains (
+    domain     TEXT PRIMARY KEY,
+    reason     TEXT,
+    blocked_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+-- Blocked actors (per local user)
+CREATE TABLE IF NOT EXISTS federation_blocked_actors (
+    local_user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    actor_url     TEXT NOT NULL,
+    created_at    TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (local_user_id, actor_url)
+);
+
+CREATE INDEX IF NOT EXISTS idx_fed_followers_user   ON federation_followers(local_user_id);
+CREATE INDEX IF NOT EXISTS idx_fed_following_user   ON federation_following(local_user_id);
+CREATE INDEX IF NOT EXISTS idx_fed_announces_object ON federation_announces(object_url);

crates/adapters/postgres/migrations/006_remote_actor_connections.sql

@@ -0,0 +1,13 @@
+CREATE TABLE remote_actor_connections (
+    id                     UUID        PRIMARY KEY DEFAULT gen_random_uuid(),
+    actor_url              TEXT        NOT NULL,
+    connection_type        TEXT        NOT NULL,
+    page                   INT         NOT NULL,
+    connected_actor_url    TEXT        NOT NULL,
+    connected_handle       TEXT        NOT NULL,
+    connected_display_name TEXT,
+    connected_avatar_url   TEXT,
+    fetched_at             TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE(actor_url, connection_type, page, connected_actor_url)
+);
+CREATE INDEX ON remote_actor_connections(actor_url, connection_type, page, fetched_at);

crates/adapters/postgres/migrations/007_content_text.sql

@@ -0,0 +1,3 @@
+-- Remote ActivityPub posts can exceed 128 characters.
+-- The 128-char limit is enforced at the application layer for local posts only.
+ALTER TABLE thoughts ALTER COLUMN content TYPE TEXT;

crates/adapters/postgres/migrations/008_rename_notifications_type.sql

@@ -0,0 +1 @@
+ALTER TABLE notifications RENAME COLUMN "type" TO notification_type;

crates/adapters/postgres/migrations/009_failed_events.sql

@@ -0,0 +1,15 @@
+CREATE TABLE failed_events (
+    id           UUID        NOT NULL DEFAULT gen_random_uuid(),
+    event_type   TEXT        NOT NULL,
+    payload      JSONB       NOT NULL,
+    failed_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
+    retry_at     TIMESTAMPTZ NOT NULL,
+    retry_count  INT         NOT NULL DEFAULT 0,
+    last_error   TEXT        NOT NULL,
+
+    CONSTRAINT failed_events_pkey PRIMARY KEY (id)
+);
+
+CREATE INDEX failed_events_due_idx
+    ON failed_events (retry_at)
+    WHERE retry_count < 3;

crates/adapters/postgres/migrations/010_fix_reply_fk_on_delete.sql

@@ -0,0 +1,11 @@
+-- Change in_reply_to_id FK from RESTRICT (default) to SET NULL.
+-- Previously, deleting a thought that had replies raised a FK violation.
+-- With SET NULL, deleting a thought orphans its replies (they survive but
+-- lose their parent reference), which is the correct semantic for a
+-- threaded social app.
+ALTER TABLE thoughts
+    DROP CONSTRAINT IF EXISTS thoughts_in_reply_to_id_fkey;
+
+ALTER TABLE thoughts
+    ADD CONSTRAINT thoughts_in_reply_to_id_fkey
+    FOREIGN KEY (in_reply_to_id) REFERENCES thoughts(id) ON DELETE SET NULL;

crates/adapters/postgres/migrations/011_outbox_events.sql

@@ -0,0 +1,10 @@
+CREATE TABLE outbox_events (
+    seq          BIGSERIAL   PRIMARY KEY,
+    aggregate_id UUID        NOT NULL,
+    event_type   TEXT        NOT NULL,
+    payload      JSONB       NOT NULL,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT now(),
+    delivered    BOOLEAN     NOT NULL DEFAULT false,
+    delivered_at TIMESTAMPTZ
+);
+CREATE INDEX outbox_events_pending_idx ON outbox_events (seq) WHERE delivered = false;

crates/adapters/postgres/src/activitypub.rs

@@ -0,0 +1,406 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+
+const MAX_REMOTE_CONTENT_CHARS: usize = 500;
+const THOUGHTS_PATH_PREFIX: &str = "/thoughts/";
+use chrono::{DateTime, Utc};
+use sqlx::PgPool;
+
+use activitypub_base::{ActivityPubRepository, ActorApUrls, OutboxEntry};
+use domain::{
+    errors::DomainError,
+    models::thought::{Thought, Visibility},
+    value_objects::{Content, ThoughtId, UserId, Username},
+};
+
+pub struct PgActivityPubRepository {
+    pool: PgPool,
+}
+
+impl PgActivityPubRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl ActivityPubRepository for PgActivityPubRepository {
+    async fn outbox_entries_for_actor(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<OutboxEntry>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            user_id: uuid::Uuid,
+            content: String,
+            created_at: DateTime<Utc>,
+            in_reply_to_id: Option<uuid::Uuid>,
+            content_warning: Option<String>,
+            sensitive: bool,
+            username: String,
+            updated_at: Option<DateTime<Utc>>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT t.id, t.user_id, t.content, t.created_at, t.in_reply_to_id, t.content_warning, t.sensitive, u.username, t.updated_at
+             FROM thoughts t JOIN users u ON u.id=t.user_id
+             WHERE t.user_id=$1 AND t.local=true AND t.visibility='public'
+             ORDER BY t.created_at DESC",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()
+        .map(|rows| {
+            rows.into_iter()
+                .map(|r| OutboxEntry {
+                    thought: Thought {
+                        id: ThoughtId::from_uuid(r.id),
+                        user_id: UserId::from_uuid(r.user_id),
+                        content: Content::new_remote(r.content),
+                        in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
+                        visibility: Visibility::Public,
+                        content_warning: r.content_warning,
+                        sensitive: r.sensitive,
+                        local: true,
+                        created_at: r.created_at,
+                        updated_at: r.updated_at,
+                    },
+                    author_username: Username::from_trusted(r.username),
+                })
+                .collect()
+        })
+    }
+
+    async fn outbox_page_for_actor(
+        &self,
+        user_id: &UserId,
+        before: Option<DateTime<Utc>>,
+        limit: usize,
+    ) -> Result<Vec<OutboxEntry>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            user_id: uuid::Uuid,
+            content: String,
+            created_at: DateTime<Utc>,
+            in_reply_to_id: Option<uuid::Uuid>,
+            content_warning: Option<String>,
+            sensitive: bool,
+            username: String,
+            updated_at: Option<DateTime<Utc>>,
+        }
+        let rows = if let Some(before) = before {
+            sqlx::query_as::<_, Row>(
+                "SELECT t.id, t.user_id, t.content, t.created_at, t.in_reply_to_id, t.content_warning, t.sensitive, u.username, t.updated_at
+                 FROM thoughts t JOIN users u ON u.id=t.user_id
+                 WHERE t.user_id=$1 AND t.local=true AND t.visibility='public' AND t.created_at < $2
+                 ORDER BY t.created_at DESC LIMIT $3",
+            )
+            .bind(user_id.as_uuid())
+            .bind(before)
+            .bind(limit as i64)
+            .fetch_all(&self.pool)
+            .await
+        } else {
+            sqlx::query_as::<_, Row>(
+                "SELECT t.id, t.user_id, t.content, t.created_at, t.in_reply_to_id, t.content_warning, t.sensitive, u.username, t.updated_at
+                 FROM thoughts t JOIN users u ON u.id=t.user_id
+                 WHERE t.user_id=$1 AND t.local=true AND t.visibility='public'
+                 ORDER BY t.created_at DESC LIMIT $2",
+            )
+            .bind(user_id.as_uuid())
+            .bind(limit as i64)
+            .fetch_all(&self.pool)
+            .await
+        }
+        .into_domain()?;
+
+        Ok(rows
+            .into_iter()
+            .map(|r| OutboxEntry {
+                thought: Thought {
+                    id: ThoughtId::from_uuid(r.id),
+                    user_id: UserId::from_uuid(r.user_id),
+                    content: Content::new_remote(r.content),
+                    in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
+                    visibility: Visibility::Public,
+                    content_warning: r.content_warning,
+                    sensitive: r.sensitive,
+                    local: true,
+                    created_at: r.created_at,
+                    updated_at: r.updated_at,
+                },
+                author_username: Username::from_trusted(r.username),
+            })
+            .collect())
+    }
+
+    async fn find_remote_actor_id(
+        &self,
+        actor_ap_url: &str,
+    ) -> Result<Option<UserId>, DomainError> {
+        sqlx::query_scalar::<_, uuid::Uuid>("SELECT id FROM users WHERE ap_id=$1")
+            .bind(actor_ap_url)
+            .fetch_optional(&self.pool)
+            .await
+            .into_domain()
+            .map(|o| o.map(UserId::from_uuid))
+    }
+
+    async fn intern_remote_actor(&self, actor_ap_url: &str) -> Result<UserId, DomainError> {
+        if let Some(id) = self.find_remote_actor_id(actor_ap_url).await? {
+            return Ok(id);
+        }
+        let new_id = uuid::Uuid::new_v4();
+        // Use the last path segment as username (e.g. /users/alice → "alice").
+        // Falls back to a random short id for long segments (e.g. UUID-based actor URLs).
+        // username column is VARCHAR(32).
+        let last_seg = url::Url::parse(actor_ap_url)
+            .ok()
+            .and_then(|u| {
+                u.path_segments()
+                    .and_then(|mut s| s.next_back().map(|s| s.to_string()))
+            })
+            .unwrap_or_default();
+        let handle = if last_seg.is_empty() {
+            format!("remote_{}", &new_id.to_string()[..13])
+        } else if last_seg.len() <= 32 {
+            last_seg
+        } else {
+            format!("remote_{}", &new_id.to_string()[..13])
+        };
+        sqlx::query(
+            "INSERT INTO users(id,username,email,password_hash,local,ap_id,created_at,updated_at)
+             VALUES($1,$2,$3,'',false,$4,NOW(),NOW()) ON CONFLICT(ap_id) DO NOTHING",
+        )
+        .bind(new_id)
+        .bind(&handle)
+        .bind(format!("{}@remote", new_id))
+        .bind(actor_ap_url)
+        .execute(&self.pool)
+        .await
+        .into_domain()?;
+        // Re-fetch to get whichever id won the race
+        self.find_remote_actor_id(actor_ap_url)
+            .await?
+            .ok_or_else(|| {
+                DomainError::Internal(
+                    "intern_remote_actor: insert succeeded but row not found".into(),
+                )
+            })
+    }
+
+    async fn update_remote_actor_display(
+        &self,
+        user_id: &UserId,
+        display_name: Option<&str>,
+        avatar_url: Option<&str>,
+    ) -> Result<(), DomainError> {
+        sqlx::query(
+            "UPDATE users SET display_name=$1, avatar_url=$2, updated_at=NOW()
+             WHERE id=$3 AND local=false",
+        )
+        .bind(display_name)
+        .bind(avatar_url)
+        .bind(user_id.as_uuid())
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn accept_note(
+        &self,
+        ap_id: &str,
+        author_id: &UserId,
+        content: &str,
+        published: DateTime<Utc>,
+        sensitive: bool,
+        content_warning: Option<String>,
+        visibility: &str,
+        in_reply_to: Option<&str>,
+    ) -> Result<ThoughtId, DomainError> {
+        let capped: String = content.chars().take(MAX_REMOTE_CONTENT_CHARS).collect();
+        let (in_reply_to_id, in_reply_to_url) = match in_reply_to {
+            Some(url) => {
+                // If the parent is a local thought, extract its UUID for in_reply_to_id.
+                let local_uuid = url::Url::parse(url).ok().and_then(|u| {
+                    u.path()
+                        .strip_prefix(THOUGHTS_PATH_PREFIX)
+                        .and_then(|s| s.split('/').next())
+                        .and_then(|s| uuid::Uuid::parse_str(s).ok())
+                });
+                (local_uuid, Some(url.to_string()))
+            }
+            None => (None, None),
+        };
+        sqlx::query(
+            "INSERT INTO thoughts(id,user_id,content,ap_id,visibility,sensitive,local,content_warning,created_at,in_reply_to_id,in_reply_to_url)
+             VALUES($1,$2,$3,$4,$8,$5,false,$6,$7,$9,$10) ON CONFLICT(ap_id) DO NOTHING",
+        )
+        .bind(uuid::Uuid::new_v4())
+        .bind(author_id.as_uuid())
+        .bind(&capped)
+        .bind(ap_id)
+        .bind(sensitive)
+        .bind(content_warning)
+        .bind(published)
+        .bind(visibility)
+        .bind(in_reply_to_id)
+        .bind(&in_reply_to_url)
+        .execute(&self.pool)
+        .await
+        .into_domain()?;
+
+        // SELECT the id — works whether the INSERT was a no-op or not (idempotent).
+        let row: (uuid::Uuid,) =
+            sqlx::query_as("SELECT id FROM thoughts WHERE ap_id=$1")
+                .bind(ap_id)
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+        Ok(ThoughtId::from_uuid(row.0))
+    }
+
+    async fn apply_note_update(&self, ap_id: &str, new_content: &str) -> Result<(), DomainError> {
+        let capped: String = new_content.chars().take(MAX_REMOTE_CONTENT_CHARS).collect();
+        sqlx::query(
+            "UPDATE thoughts SET content=$2,updated_at=NOW() WHERE ap_id=$1 AND local=false",
+        )
+        .bind(ap_id)
+        .bind(&capped)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn retract_note(&self, ap_id: &str) -> Result<(), DomainError> {
+        sqlx::query("DELETE FROM thoughts WHERE ap_id=$1 AND local=false")
+            .bind(ap_id)
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+
+    async fn retract_actor_notes(&self, actor_ap_url: &str) -> Result<(), DomainError> {
+        sqlx::query(
+            "DELETE FROM thoughts WHERE local=false AND user_id=(SELECT id FROM users WHERE ap_id=$1)",
+        )
+        .bind(actor_ap_url)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn count_local_notes(&self) -> Result<u64, DomainError> {
+        let n: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM thoughts WHERE local=true")
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()?;
+        Ok(n as u64)
+    }
+
+    async fn get_thought_ap_id(
+        &self,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<String>, DomainError> {
+        sqlx::query_scalar::<_, String>(
+            "SELECT ap_id FROM thoughts WHERE id = $1 AND ap_id IS NOT NULL",
+        )
+        .bind(thought_id.as_uuid())
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()
+    }
+
+    async fn get_actor_ap_urls(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Option<ActorApUrls>, DomainError> {
+        sqlx::query_as::<_, (String, String)>(
+            "SELECT ap_id, inbox_url FROM users \
+             WHERE id = $1 AND ap_id IS NOT NULL AND inbox_url IS NOT NULL",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()
+        .map(|opt| opt.map(|(ap_id, inbox_url)| ActorApUrls { ap_id, inbox_url }))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use activitypub_base::ActivityPubRepository;
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn intern_remote_actor_is_idempotent(pool: sqlx::PgPool) {
+        let repo = PgActivityPubRepository::new(pool);
+        let url = "https://mastodon.social/users/alice";
+        let id1 = repo.intern_remote_actor(url).await.unwrap();
+        let id2 = repo.intern_remote_actor(url).await.unwrap();
+        assert_eq!(id1, id2);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn accept_and_retract_note(pool: sqlx::PgPool) {
+        let repo = PgActivityPubRepository::new(pool);
+        let actor_url = "https://remote.example/users/bob";
+        let ap_id = "https://remote.example/notes/1";
+        let author = repo.intern_remote_actor(actor_url).await.unwrap();
+        repo.accept_note(
+            ap_id,
+            &author,
+            "hello from remote",
+            chrono::Utc::now(),
+            false,
+            None,
+            "public",
+            None,
+        )
+        .await
+        .unwrap();
+        repo.retract_note(ap_id).await.unwrap();
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn count_local_notes_excludes_remote(pool: sqlx::PgPool) {
+        let repo = PgActivityPubRepository::new(pool);
+        assert_eq!(repo.count_local_notes().await.unwrap(), 0);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn accept_note_returns_thought_id(pool: sqlx::PgPool) {
+        let repo = PgActivityPubRepository::new(pool.clone());
+        let actor_user_id = repo
+            .intern_remote_actor("https://remote.example/users/alice")
+            .await
+            .unwrap();
+
+        let thought_id = repo
+            .accept_note(
+                "https://remote.example/notes/1",
+                &actor_user_id,
+                "Hello #rust world",
+                chrono::Utc::now(),
+                false,
+                None,
+                "public",
+                None,
+            )
+            .await
+            .unwrap();
+
+        let row: (uuid::Uuid,) = sqlx::query_as("SELECT id FROM thoughts WHERE ap_id=$1")
+            .bind("https://remote.example/notes/1")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+        assert_eq!(thought_id.as_uuid(), row.0);
+    }
+}

crates/adapters/postgres/src/api_key.rs

@@ -0,0 +1,142 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use domain::{
+    errors::DomainError,
+    models::api_key::ApiKey,
+    ports::ApiKeyRepository,
+    value_objects::{ApiKeyId, UserId},
+};
+use sqlx::PgPool;
+
+pub struct PgApiKeyRepository {
+    pool: PgPool,
+}
+impl PgApiKeyRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl ApiKeyRepository for PgApiKeyRepository {
+    async fn save(&self, k: &ApiKey) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO api_keys(id,user_id,key_hash,name,created_at) VALUES($1,$2,$3,$4,$5)",
+        )
+        .bind(k.id.as_uuid())
+        .bind(k.user_id.as_uuid())
+        .bind(&k.key_hash)
+        .bind(&k.name)
+        .bind(k.created_at)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn find_by_hash(&self, hash: &str) -> Result<Option<ApiKey>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            user_id: uuid::Uuid,
+            key_hash: String,
+            name: String,
+            created_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT id,user_id,key_hash,name,created_at FROM api_keys WHERE key_hash=$1",
+        )
+        .bind(hash)
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()
+        .map(|o| {
+            o.map(|r| ApiKey {
+                id: ApiKeyId::from_uuid(r.id),
+                user_id: UserId::from_uuid(r.user_id),
+                key_hash: r.key_hash,
+                name: r.name,
+                created_at: r.created_at,
+            })
+        })
+    }
+
+    async fn list_for_user(&self, user_id: &UserId) -> Result<Vec<ApiKey>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            user_id: uuid::Uuid,
+            key_hash: String,
+            name: String,
+            created_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>("SELECT id,user_id,key_hash,name,created_at FROM api_keys WHERE user_id=$1 ORDER BY created_at DESC")
+            .bind(user_id.as_uuid()).fetch_all(&self.pool).await
+            .into_domain()
+            .map(|rows| rows.into_iter().map(|r| ApiKey { id: ApiKeyId::from_uuid(r.id), user_id: UserId::from_uuid(r.user_id), key_hash: r.key_hash, name: r.name, created_at: r.created_at }).collect())
+    }
+
+    async fn delete(&self, id: &ApiKeyId, user_id: &UserId) -> Result<(), DomainError> {
+        sqlx::query("DELETE FROM api_keys WHERE id=$1 AND user_id=$2")
+            .bind(id.as_uuid())
+            .bind(user_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::user::PgUserRepository;
+    use chrono::Utc;
+    use domain::ports::UserWriter;
+    use domain::{models::user::User, value_objects::*};
+
+    async fn seed_user(pool: &sqlx::PgPool) -> User {
+        let repo = PgUserRepository::new(pool.clone());
+        let u = User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        );
+        repo.save(&u).await.unwrap();
+        u
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn save_and_find_by_hash(pool: sqlx::PgPool) {
+        let user = seed_user(&pool).await;
+        let repo = PgApiKeyRepository::new(pool);
+        let key = ApiKey {
+            id: ApiKeyId::new(),
+            user_id: user.id.clone(),
+            key_hash: "abc123".into(),
+            name: "test".into(),
+            created_at: Utc::now(),
+        };
+        repo.save(&key).await.unwrap();
+        let found = repo.find_by_hash("abc123").await.unwrap().unwrap();
+        assert_eq!(found.name, "test");
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_key(pool: sqlx::PgPool) {
+        let user = seed_user(&pool).await;
+        let repo = PgApiKeyRepository::new(pool);
+        let key = ApiKey {
+            id: ApiKeyId::new(),
+            user_id: user.id.clone(),
+            key_hash: "def456".into(),
+            name: "key2".into(),
+            created_at: Utc::now(),
+        };
+        repo.save(&key).await.unwrap();
+        repo.delete(&key.id, &user.id).await.unwrap();
+        assert!(repo.find_by_hash("def456").await.unwrap().is_none());
+    }
+}

crates/adapters/postgres/src/block.rs

@@ -0,0 +1,90 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError, models::social::Block, ports::BlockRepository, value_objects::UserId,
+};
+use sqlx::PgPool;
+
+pub struct PgBlockRepository {
+    pool: PgPool,
+}
+impl PgBlockRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl BlockRepository for PgBlockRepository {
+    async fn save(&self, b: &Block) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO blocks(blocker_id,blocked_id,created_at) VALUES($1,$2,$3) ON CONFLICT DO NOTHING"
+        )
+        .bind(b.blocker_id.as_uuid())
+        .bind(b.blocked_id.as_uuid())
+        .bind(b.created_at)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn delete(&self, blocker_id: &UserId, blocked_id: &UserId) -> Result<(), DomainError> {
+        sqlx::query("DELETE FROM blocks WHERE blocker_id=$1 AND blocked_id=$2")
+            .bind(blocker_id.as_uuid())
+            .bind(blocked_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+
+    async fn exists(&self, blocker_id: &UserId, blocked_id: &UserId) -> Result<bool, DomainError> {
+        let count: i64 =
+            sqlx::query_scalar("SELECT COUNT(*) FROM blocks WHERE blocker_id=$1 AND blocked_id=$2")
+                .bind(blocker_id.as_uuid())
+                .bind(blocked_id.as_uuid())
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+        Ok(count > 0)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::seed_user;
+    use chrono::Utc;
+    use domain::value_objects::*;
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn block_exists(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgBlockRepository::new(pool);
+        let block = Block {
+            blocker_id: alice.id.clone(),
+            blocked_id: bob.id.clone(),
+            created_at: Utc::now(),
+        };
+        repo.save(&block).await.unwrap();
+        assert!(repo.exists(&alice.id, &bob.id).await.unwrap());
+        assert!(!repo.exists(&bob.id, &alice.id).await.unwrap());
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn unblock(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgBlockRepository::new(pool);
+        let block = Block {
+            blocker_id: alice.id.clone(),
+            blocked_id: bob.id.clone(),
+            created_at: Utc::now(),
+        };
+        repo.save(&block).await.unwrap();
+        repo.delete(&alice.id, &bob.id).await.unwrap();
+        assert!(!repo.exists(&alice.id, &bob.id).await.unwrap());
+    }
+}

crates/adapters/postgres/src/boost.rs

@@ -0,0 +1,110 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use domain::{
+    errors::DomainError,
+    models::social::Boost,
+    ports::BoostRepository,
+    value_objects::{BoostId, ThoughtId, UserId},
+};
+use sqlx::PgPool;
+
+pub struct PgBoostRepository {
+    pool: PgPool,
+}
+impl PgBoostRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl BoostRepository for PgBoostRepository {
+    async fn save(&self, b: &Boost) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO boosts(id,user_id,thought_id,ap_id,created_at) VALUES($1,$2,$3,$4,$5) ON CONFLICT(user_id,thought_id) DO NOTHING"
+        )
+        .bind(b.id.as_uuid()).bind(b.user_id.as_uuid()).bind(b.thought_id.as_uuid()).bind(&b.ap_id).bind(b.created_at)
+        .execute(&self.pool).await.into_domain().map(|_| ())
+    }
+
+    async fn delete(&self, user_id: &UserId, thought_id: &ThoughtId) -> Result<(), DomainError> {
+        let r = sqlx::query("DELETE FROM boosts WHERE user_id=$1 AND thought_id=$2")
+            .bind(user_id.as_uuid())
+            .bind(thought_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()?;
+        if r.rows_affected() == 0 {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+
+    async fn find(
+        &self,
+        user_id: &UserId,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<Boost>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            user_id: uuid::Uuid,
+            thought_id: uuid::Uuid,
+            ap_id: Option<String>,
+            created_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>("SELECT id,user_id,thought_id,ap_id,created_at FROM boosts WHERE user_id=$1 AND thought_id=$2")
+            .bind(user_id.as_uuid()).bind(thought_id.as_uuid())
+            .fetch_optional(&self.pool).await
+            .into_domain()
+            .map(|o| o.map(|r| Boost { id: BoostId::from_uuid(r.id), user_id: UserId::from_uuid(r.user_id), thought_id: ThoughtId::from_uuid(r.thought_id), ap_id: r.ap_id, created_at: r.created_at }))
+    }
+
+    async fn count_for_thought(&self, thought_id: &ThoughtId) -> Result<i64, DomainError> {
+        sqlx::query_scalar("SELECT COUNT(*) FROM boosts WHERE thought_id=$1")
+            .bind(thought_id.as_uuid())
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::seed_user_and_thought;
+    use chrono::Utc;
+    use domain::value_objects::*;
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn boost_and_count(pool: sqlx::PgPool) {
+        let (user, thought) = seed_user_and_thought(&pool).await;
+        let repo = PgBoostRepository::new(pool);
+        let boost = Boost {
+            id: BoostId::new(),
+            user_id: user.id.clone(),
+            thought_id: thought.id.clone(),
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&boost).await.unwrap();
+        assert_eq!(repo.count_for_thought(&thought.id).await.unwrap(), 1);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn unboost(pool: sqlx::PgPool) {
+        let (user, thought) = seed_user_and_thought(&pool).await;
+        let repo = PgBoostRepository::new(pool);
+        let boost = Boost {
+            id: BoostId::new(),
+            user_id: user.id.clone(),
+            thought_id: thought.id.clone(),
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&boost).await.unwrap();
+        repo.delete(&user.id, &thought.id).await.unwrap();
+        assert_eq!(repo.count_for_thought(&thought.id).await.unwrap(), 0);
+    }
+}

crates/adapters/postgres/src/db_error.rs

@@ -0,0 +1,20 @@
+use domain::errors::DomainError;
+
+pub(crate) trait IntoDbResult<T> {
+    fn into_domain(self) -> Result<T, DomainError>;
+}
+
+impl<T> IntoDbResult<T> for Result<T, sqlx::Error> {
+    fn into_domain(self) -> Result<T, DomainError> {
+        self.map_err(|e| {
+            if let sqlx::Error::Database(ref db) = e {
+                if db.code().as_deref() == Some("23505") {
+                    return DomainError::Conflict(
+                        db.constraint().unwrap_or("conflict").to_string(),
+                    );
+                }
+            }
+            DomainError::Internal(e.to_string())
+        })
+    }
+}

crates/adapters/postgres/src/engagement.rs

@@ -0,0 +1,83 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    models::feed::{EngagementStats, ViewerContext},
+    ports::EngagementRepository,
+    value_objects::{ThoughtId, UserId},
+};
+use sqlx::PgPool;
+use std::collections::HashMap;
+
+pub struct PgEngagementRepository {
+    pool: PgPool,
+}
+
+impl PgEngagementRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl EngagementRepository for PgEngagementRepository {
+    async fn get_for_thoughts(
+        &self,
+        thought_ids: &[ThoughtId],
+        viewer_id: Option<&UserId>,
+    ) -> Result<HashMap<ThoughtId, (EngagementStats, Option<ViewerContext>)>, DomainError> {
+        if thought_ids.is_empty() {
+            return Ok(HashMap::new());
+        }
+
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            thought_id: uuid::Uuid,
+            like_count: i64,
+            boost_count: i64,
+            reply_count: i64,
+            liked_by_viewer: bool,
+            boosted_by_viewer: bool,
+        }
+
+        let ids: Vec<uuid::Uuid> = thought_ids.iter().map(|t| t.as_uuid()).collect();
+        let viewer_uuid: Option<uuid::Uuid> = viewer_id.map(|v| v.as_uuid());
+
+        let rows = sqlx::query_as::<_, Row>(
+            "SELECT
+                t.id AS thought_id,
+                COUNT(DISTINCT l.user_id) AS like_count,
+                COUNT(DISTINCT b.user_id) AS boost_count,
+                COUNT(DISTINCT r.id) AS reply_count,
+                COALESCE(BOOL_OR(l.user_id = $2), false) AS liked_by_viewer,
+                COALESCE(BOOL_OR(b.user_id = $2), false) AS boosted_by_viewer
+             FROM thoughts t
+             LEFT JOIN likes l ON l.thought_id = t.id
+             LEFT JOIN boosts b ON b.thought_id = t.id
+             LEFT JOIN thoughts r ON r.in_reply_to_id = t.id
+             WHERE t.id = ANY($1)
+             GROUP BY t.id",
+        )
+        .bind(&ids[..])
+        .bind(viewer_uuid)
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        let mut result = HashMap::new();
+        for row in rows {
+            let tid = ThoughtId::from_uuid(row.thought_id);
+            let stats = EngagementStats {
+                like_count: row.like_count,
+                boost_count: row.boost_count,
+                reply_count: row.reply_count,
+            };
+            let viewer = viewer_id.map(|_| ViewerContext {
+                liked: row.liked_by_viewer,
+                boosted: row.boosted_by_viewer,
+            });
+            result.insert(tid, (stats, viewer));
+        }
+        Ok(result)
+    }
+}

crates/adapters/postgres/src/failed_event.rs

@@ -0,0 +1,105 @@
+use chrono::{DateTime, Utc};
+use sqlx::PgPool;
+
+/// How many times a failed event is retried by the DLQ processor.
+pub const DLQ_MAX_RETRIES: i32 = 3;
+/// Quarantine period for the first DLQ retry (seconds). Doubles each retry.
+pub const DLQ_INITIAL_BACKOFF_SECS: i64 = 300; // 5 minutes
+/// How often the DLQ processor polls for due retries (seconds).
+pub const DLQ_POLL_INTERVAL_SECS: u64 = 60;
+
+#[derive(sqlx::FromRow)]
+pub struct FailedEvent {
+    pub id: uuid::Uuid,
+    pub event_type: String,
+    pub payload: serde_json::Value,
+    pub failed_at: DateTime<Utc>,
+    pub retry_at: DateTime<Utc>,
+    pub retry_count: i32,
+    pub last_error: String,
+}
+
+pub struct PgFailedEventStore {
+    pool: PgPool,
+}
+
+impl PgFailedEventStore {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+
+    /// Insert a newly exhausted event into the DLQ.
+    pub async fn insert(
+        &self,
+        event_type: &str,
+        payload: &serde_json::Value,
+        last_error: &str,
+    ) -> Result<(), sqlx::Error> {
+        let retry_at = Utc::now() + chrono::Duration::seconds(DLQ_INITIAL_BACKOFF_SECS);
+        sqlx::query(
+            "INSERT INTO failed_events \
+             (event_type, payload, retry_at, last_error) \
+             VALUES ($1, $2, $3, $4)",
+        )
+        .bind(event_type)
+        .bind(payload)
+        .bind(retry_at)
+        .bind(last_error)
+        .execute(&self.pool)
+        .await?;
+        Ok(())
+    }
+
+    /// Fetch all events due for retry (retry_at <= now, retry_count < DLQ_MAX_RETRIES).
+    pub async fn poll_due(&self) -> Result<Vec<FailedEvent>, sqlx::Error> {
+        sqlx::query_as::<_, FailedEvent>(
+            "SELECT id, event_type, payload, failed_at, retry_at, retry_count, last_error \
+             FROM failed_events \
+             WHERE retry_at <= now() AND retry_count < $1 \
+             ORDER BY retry_at \
+             LIMIT 100",
+        )
+        .bind(DLQ_MAX_RETRIES)
+        .fetch_all(&self.pool)
+        .await
+    }
+
+    /// Advance a row after a republish attempt using exponential backoff.
+    /// next_retry = now + initial * 2^retry_count
+    pub async fn advance(&self, id: uuid::Uuid, error: Option<&str>) -> Result<(), sqlx::Error> {
+        let current: i32 =
+            sqlx::query_scalar("SELECT retry_count FROM failed_events WHERE id = $1")
+                .bind(id)
+                .fetch_one(&self.pool)
+                .await?;
+
+        let new_count = current + 1;
+        let backoff_secs = DLQ_INITIAL_BACKOFF_SECS * (1_i64 << new_count.min(10));
+        let retry_at = Utc::now() + chrono::Duration::seconds(backoff_secs);
+        let last_error = error.unwrap_or("republish succeeded");
+
+        sqlx::query(
+            "UPDATE failed_events \
+             SET retry_count = $1, retry_at = $2, last_error = $3 \
+             WHERE id = $4",
+        )
+        .bind(new_count)
+        .bind(retry_at)
+        .bind(last_error)
+        .bind(id)
+        .execute(&self.pool)
+        .await?;
+        Ok(())
+    }
+
+    /// Park a permanently failed event (retry_count >= DLQ_MAX_RETRIES).
+    pub async fn park_permanently(&self, id: uuid::Uuid) -> Result<(), sqlx::Error> {
+        let far_future = Utc::now() + chrono::Duration::days(365);
+        sqlx::query("UPDATE failed_events SET retry_at = $1 WHERE id = $2")
+            .bind(far_future)
+            .bind(id)
+            .execute(&self.pool)
+            .await?;
+        Ok(())
+    }
+}

crates/adapters/postgres/src/feed.rs

@@ -0,0 +1,399 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{FeedEntry, Paginated},
+        thought::{Thought, Visibility},
+        user::User,
+    },
+    ports::{FeedQuery, FeedRepository, FeedScope},
+    value_objects::{Content, Email, PasswordHash, ThoughtId, UserId, Username},
+};
+use sqlx::PgPool;
+
+pub struct PgFeedRepository {
+    pool: PgPool,
+}
+impl PgFeedRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[derive(sqlx::FromRow)]
+struct FeedRow {
+    thought_id: uuid::Uuid,
+    t_user_id: uuid::Uuid,
+    content: String,
+    in_reply_to_id: Option<uuid::Uuid>,
+    visibility: String,
+    content_warning: Option<String>,
+    sensitive: bool,
+    t_local: bool,
+    thought_created_at: DateTime<Utc>,
+    updated_at: Option<DateTime<Utc>>,
+    author_id: uuid::Uuid,
+    username: String,
+    email: String,
+    password_hash: String,
+    display_name: Option<String>,
+    bio: Option<String>,
+    avatar_url: Option<String>,
+    header_url: Option<String>,
+    custom_css: Option<String>,
+    author_local: bool,
+    author_created_at: DateTime<Utc>,
+    author_updated_at: DateTime<Utc>,
+    like_count: i64,
+    boost_count: i64,
+    reply_count: i64,
+    liked_by_viewer: bool,
+    boosted_by_viewer: bool,
+}
+
+fn federation_following_clause(follower: Option<uuid::Uuid>) -> String {
+    match follower {
+        Some(fid) => format!(
+            " OR t.user_id IN (
+                SELECT u2.id FROM users u2
+                JOIN federation_following ff ON u2.ap_id = ff.remote_actor_url
+                WHERE ff.local_user_id = '{fid}'
+            )"
+        ),
+        None => String::new(),
+    }
+}
+
+fn feed_select(viewer: Option<uuid::Uuid>) -> String {
+    let viewer_checks = match viewer {
+        Some(uid) => format!(
+            "EXISTS(SELECT 1 FROM likes WHERE user_id='{uid}' AND thought_id=t.id) AS liked_by_viewer,
+             EXISTS(SELECT 1 FROM boosts WHERE user_id='{uid}' AND thought_id=t.id) AS boosted_by_viewer"
+        ),
+        None => "false AS liked_by_viewer, false AS boosted_by_viewer".to_string(),
+    };
+    format!(
+        "
+    SELECT
+        t.id AS thought_id, t.user_id AS t_user_id, t.content,
+        t.in_reply_to_id,
+        t.visibility, t.content_warning, t.sensitive, t.local AS t_local,
+        t.created_at AS thought_created_at, t.updated_at,
+        u.id AS author_id,
+        CASE WHEN NOT u.local AND ra.handle IS NOT NULL AND ra.handle != ''
+             THEN '@' || ra.handle ||
+                  CASE WHEN ra.handle NOT LIKE '%@%'
+                       THEN '@' || SPLIT_PART(ra.url, '/', 3)
+                       ELSE '' END
+             ELSE u.username END AS username,
+        u.email, u.password_hash,
+        COALESCE(ra.display_name, u.display_name) AS display_name,
+        u.bio,
+        COALESCE(ra.avatar_url, u.avatar_url) AS avatar_url,
+        u.header_url, u.custom_css,
+        u.local AS author_local,
+        u.created_at AS author_created_at, u.updated_at AS author_updated_at,
+        (SELECT COUNT(*) FROM likes l WHERE l.thought_id=t.id) AS like_count,
+        (SELECT COUNT(*) FROM boosts b WHERE b.thought_id=t.id) AS boost_count,
+        (SELECT COUNT(*) FROM thoughts r WHERE r.in_reply_to_id=t.id) AS reply_count,
+        {viewer_checks}
+    FROM thoughts t
+    JOIN users u ON u.id=t.user_id
+    LEFT JOIN remote_actors ra ON u.ap_id = ra.url"
+    )
+}
+
+fn row_to_entry(r: FeedRow, viewer: Option<uuid::Uuid>) -> Result<FeedEntry, DomainError> {
+    let thought = Thought {
+        id: ThoughtId::from_uuid(r.thought_id),
+        user_id: UserId::from_uuid(r.t_user_id),
+        content: Content::new_remote(r.content),
+        in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
+        visibility: Visibility::from_db_str(&r.visibility)?,
+        content_warning: r.content_warning,
+        sensitive: r.sensitive,
+        local: r.t_local,
+        created_at: r.thought_created_at,
+        updated_at: r.updated_at,
+    };
+    let author = User {
+        id: UserId::from_uuid(r.author_id),
+        username: Username::from_trusted(r.username),
+        email: Email::from_trusted(r.email),
+        password_hash: PasswordHash(r.password_hash),
+        display_name: r.display_name,
+        bio: r.bio,
+        avatar_url: r.avatar_url,
+        header_url: r.header_url,
+        custom_css: r.custom_css,
+        local: r.author_local,
+        created_at: r.author_created_at,
+        updated_at: r.author_updated_at,
+    };
+    Ok(FeedEntry {
+        thought,
+        author,
+        stats: domain::models::feed::EngagementStats {
+            like_count: r.like_count,
+            boost_count: r.boost_count,
+            reply_count: r.reply_count,
+        },
+        viewer: viewer.map(|_| domain::models::feed::ViewerContext {
+            liked: r.liked_by_viewer,
+            boosted: r.boosted_by_viewer,
+        }),
+    })
+}
+
+#[async_trait]
+impl FeedRepository for PgFeedRepository {
+    async fn query(&self, q: &FeedQuery) -> Result<Paginated<FeedEntry>, DomainError> {
+        let viewer = q.viewer_id.as_ref().map(|v| v.as_uuid());
+        let page = &q.page;
+
+        match &q.scope {
+            FeedScope::Home { following_ids } => {
+                let ids: Vec<uuid::Uuid> = following_ids.iter().map(|id| id.as_uuid()).collect();
+                let fed_clause = federation_following_clause(viewer);
+                let count_sql = format!(
+                    "SELECT COUNT(*) FROM thoughts t WHERE (t.user_id=ANY($1){}) AND t.visibility != 'direct'",
+                    fed_clause
+                );
+                let total: i64 = sqlx::query_scalar(&count_sql)
+                    .bind(&ids)
+                    .fetch_one(&self.pool)
+                    .await
+                    .into_domain()?;
+
+                let sel = feed_select(viewer);
+                let sql = format!("{sel} WHERE (t.user_id=ANY($1){}) AND t.visibility != 'direct' ORDER BY t.created_at DESC LIMIT $2 OFFSET $3", fed_clause);
+                let rows = sqlx::query_as::<_, FeedRow>(&sql)
+                    .bind(&ids)
+                    .bind(page.limit())
+                    .bind(page.offset())
+                    .fetch_all(&self.pool)
+                    .await
+                    .into_domain()?;
+
+                Ok(Paginated {
+                    items: rows
+                        .into_iter()
+                        .map(|r| row_to_entry(r, viewer))
+                        .collect::<Result<Vec<_>, _>>()?,
+                    total,
+                    page: page.page,
+                    per_page: page.per_page,
+                })
+            }
+
+            FeedScope::Public => {
+                let total: i64 = sqlx::query_scalar(
+                    "SELECT COUNT(*) FROM thoughts t WHERE t.local=true AND t.visibility='public'",
+                )
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+
+                let sel = feed_select(viewer);
+                let sql = format!("{sel} WHERE t.local=true AND t.visibility='public' ORDER BY t.created_at DESC LIMIT $1 OFFSET $2");
+                let rows = sqlx::query_as::<_, FeedRow>(&sql)
+                    .bind(page.limit())
+                    .bind(page.offset())
+                    .fetch_all(&self.pool)
+                    .await
+                    .into_domain()?;
+
+                Ok(Paginated {
+                    items: rows
+                        .into_iter()
+                        .map(|r| row_to_entry(r, viewer))
+                        .collect::<Result<Vec<_>, _>>()?,
+                    total,
+                    page: page.page,
+                    per_page: page.per_page,
+                })
+            }
+
+            FeedScope::Search { query } => {
+                let total: i64 = sqlx::query_scalar(
+                    "SELECT COUNT(*) FROM thoughts t WHERE t.content % $1 AND t.visibility='public'",
+                )
+                .bind(query)
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+
+                let sel = feed_select(viewer);
+                let sql = format!("{sel} WHERE t.content % $1 AND t.visibility='public' ORDER BY similarity(t.content, $1) DESC LIMIT $2 OFFSET $3");
+                let rows = sqlx::query_as::<_, FeedRow>(&sql)
+                    .bind(query)
+                    .bind(page.limit())
+                    .bind(page.offset())
+                    .fetch_all(&self.pool)
+                    .await
+                    .into_domain()?;
+
+                Ok(Paginated {
+                    items: rows
+                        .into_iter()
+                        .map(|r| row_to_entry(r, viewer))
+                        .collect::<Result<Vec<_>, _>>()?,
+                    total,
+                    page: page.page,
+                    per_page: page.per_page,
+                })
+            }
+
+            FeedScope::Tag { tag_name } => {
+                let total: i64 = sqlx::query_scalar(
+                    "SELECT COUNT(*) FROM thoughts t
+                     JOIN thought_tags tt ON tt.thought_id = t.id
+                     JOIN tags tg ON tg.id = tt.tag_id
+                     WHERE tg.name = $1 AND t.visibility = 'public'",
+                )
+                .bind(tag_name)
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+
+                let sel = feed_select(viewer);
+                let sql = format!(
+                    "{sel}
+                     JOIN thought_tags tt ON tt.thought_id = t.id
+                     JOIN tags tg ON tg.id = tt.tag_id
+                     WHERE tg.name = $1 AND t.visibility = 'public'
+                     ORDER BY t.created_at DESC LIMIT $2 OFFSET $3"
+                );
+                let rows = sqlx::query_as::<_, FeedRow>(&sql)
+                    .bind(tag_name)
+                    .bind(page.limit())
+                    .bind(page.offset())
+                    .fetch_all(&self.pool)
+                    .await
+                    .into_domain()?;
+
+                Ok(Paginated {
+                    items: rows
+                        .into_iter()
+                        .map(|r| row_to_entry(r, viewer))
+                        .collect::<Result<Vec<_>, _>>()?,
+                    total,
+                    page: page.page,
+                    per_page: page.per_page,
+                })
+            }
+
+            FeedScope::User { user_id } => {
+                let uid = user_id.as_uuid();
+                // Use nil UUID for unauthenticated viewers — won't match owner or follower checks.
+                let viewer_uuid = viewer.unwrap_or(uuid::Uuid::nil());
+
+                let total: i64 = sqlx::query_scalar(
+                    "SELECT COUNT(*) FROM thoughts t WHERE t.user_id = $1 AND ($2::uuid = $1 OR (t.visibility != 'direct' AND (t.visibility IN ('public', 'unlisted') OR (t.visibility = 'followers' AND EXISTS(SELECT 1 FROM follows WHERE follower_id = $2 AND following_id = $1 AND state = 'accepted')))))",
+                )
+                .bind(uid)
+                .bind(viewer_uuid)
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+
+                let sel = feed_select(viewer);
+                let sql = format!("{sel} WHERE t.user_id = $1 AND ($4::uuid = $1 OR (t.visibility != 'direct' AND (t.visibility IN ('public', 'unlisted') OR (t.visibility = 'followers' AND EXISTS(SELECT 1 FROM follows WHERE follower_id = $4 AND following_id = $1 AND state = 'accepted'))))) ORDER BY t.created_at DESC LIMIT $2 OFFSET $3");
+                let rows = sqlx::query_as::<_, FeedRow>(&sql)
+                    .bind(uid)
+                    .bind(page.limit())
+                    .bind(page.offset())
+                    .bind(viewer_uuid)
+                    .fetch_all(&self.pool)
+                    .await
+                    .into_domain()?;
+
+                Ok(Paginated {
+                    items: rows
+                        .into_iter()
+                        .map(|r| row_to_entry(r, viewer))
+                        .collect::<Result<Vec<_>, _>>()?,
+                    total,
+                    page: page.page,
+                    per_page: page.per_page,
+                })
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{thought::PgThoughtRepository, user::PgUserRepository};
+    use domain::{
+        models::{
+            feed::PageParams,
+            thought::{Thought, Visibility},
+            user::User,
+        },
+        ports::{FeedQuery, ThoughtRepository, UserWriter},
+        value_objects::*,
+    };
+
+    async fn seed(pool: &sqlx::PgPool, username: &str, content: &str) -> (User, Thought) {
+        let urepo = PgUserRepository::new(pool.clone());
+        let trepo = PgThoughtRepository::new(pool.clone());
+        let u = User::new_local(
+            UserId::new(),
+            Username::new(username).unwrap(),
+            Email::new(format!("{username}@ex.com")).unwrap(),
+            PasswordHash("h".into()),
+        );
+        urepo.save(&u).await.unwrap();
+        let t = Thought::new_local(
+            ThoughtId::new(),
+            u.id.clone(),
+            Content::new_local(content).unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        trepo.save(&t).await.unwrap();
+        (u, t)
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn public_feed_returns_local_thoughts(pool: sqlx::PgPool) {
+        let (_, _) = seed(&pool, "alice", "hello").await;
+        let repo = PgFeedRepository::new(pool);
+        let result = repo
+            .query(&FeedQuery::public(
+                PageParams { page: 1, per_page: 20 },
+                None,
+            ))
+            .await
+            .unwrap();
+        assert_eq!(result.total, 1);
+        assert_eq!(result.items[0].thought.content.as_str(), "hello");
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn search_returns_matching_thoughts(pool: sqlx::PgPool) {
+        let (_, _) = seed(&pool, "alice", "hello world").await;
+        let (_, _) = seed(&pool, "bob", "goodbye world").await;
+        let repo = PgFeedRepository::new(pool);
+        let result = repo
+            .query(&FeedQuery::search(
+                "hello world",
+                PageParams { page: 1, per_page: 20 },
+                None,
+            ))
+            .await
+            .unwrap();
+        assert!(result.total >= 1);
+        assert!(result
+            .items
+            .iter()
+            .any(|e| e.thought.content.as_str() == "hello world"));
+    }
+}

crates/adapters/postgres/src/follow.rs

@@ -0,0 +1,252 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{PageParams, Paginated},
+        social::{Follow, FollowState},
+        user::User,
+    },
+    ports::FollowRepository,
+    value_objects::UserId,
+};
+use sqlx::PgPool;
+
+pub struct PgFollowRepository {
+    pool: PgPool,
+}
+impl PgFollowRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl FollowRepository for PgFollowRepository {
+    async fn save(&self, f: &Follow) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO follows(follower_id,following_id,state,ap_id,created_at)
+             VALUES($1,$2,$3,$4,$5)
+             ON CONFLICT(follower_id,following_id) DO UPDATE SET state=EXCLUDED.state,ap_id=EXCLUDED.ap_id"
+        )
+        .bind(f.follower_id.as_uuid())
+        .bind(f.following_id.as_uuid())
+        .bind(f.state.as_str())
+        .bind(&f.ap_id)
+        .bind(f.created_at)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn delete(&self, follower_id: &UserId, following_id: &UserId) -> Result<(), DomainError> {
+        let r = sqlx::query("DELETE FROM follows WHERE follower_id=$1 AND following_id=$2")
+            .bind(follower_id.as_uuid())
+            .bind(following_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()?;
+        if r.rows_affected() == 0 {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+
+    async fn find(
+        &self,
+        follower_id: &UserId,
+        following_id: &UserId,
+    ) -> Result<Option<Follow>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            follower_id: uuid::Uuid,
+            following_id: uuid::Uuid,
+            state: String,
+            ap_id: Option<String>,
+            created_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT follower_id,following_id,state,ap_id,created_at FROM follows WHERE follower_id=$1 AND following_id=$2"
+        )
+        .bind(follower_id.as_uuid())
+        .bind(following_id.as_uuid())
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()
+        .and_then(|o| {
+            o.map(|r| {
+                Ok(Follow {
+                    follower_id: UserId::from_uuid(r.follower_id),
+                    following_id: UserId::from_uuid(r.following_id),
+                    state: FollowState::from_db_str(&r.state)?,
+                    ap_id: r.ap_id,
+                    created_at: r.created_at,
+                })
+            })
+            .transpose()
+        })
+    }
+
+    async fn update_state(
+        &self,
+        follower_id: &UserId,
+        following_id: &UserId,
+        state: &FollowState,
+    ) -> Result<(), DomainError> {
+        sqlx::query("UPDATE follows SET state=$3 WHERE follower_id=$1 AND following_id=$2")
+            .bind(follower_id.as_uuid())
+            .bind(following_id.as_uuid())
+            .bind(state.as_str())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+
+    async fn list_followers(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<User>, DomainError> {
+        let total: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM follows WHERE following_id=$1 AND state='accepted'",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_one(&self.pool)
+        .await
+        .into_domain()?;
+
+        let rows = sqlx::query_as::<_, crate::user::UserRow>(
+            "SELECT u.id,u.username,u.email,u.password_hash,u.display_name,u.bio,u.avatar_url,u.header_url,u.custom_css,u.local,u.ap_id,u.inbox_url,u.created_at,u.updated_at
+             FROM users u JOIN follows f ON f.follower_id=u.id
+             WHERE f.following_id=$1 AND f.state='accepted'
+             ORDER BY f.created_at DESC LIMIT $2 OFFSET $3"
+        )
+        .bind(user_id.as_uuid())
+        .bind(page.limit())
+        .bind(page.offset())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(Paginated {
+            items: rows.into_iter().map(User::from).collect(),
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+
+    async fn list_following(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<User>, DomainError> {
+        let total: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM follows WHERE follower_id=$1 AND state='accepted'",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_one(&self.pool)
+        .await
+        .into_domain()?;
+
+        let rows = sqlx::query_as::<_, crate::user::UserRow>(
+            "SELECT u.id,u.username,u.email,u.password_hash,u.display_name,u.bio,u.avatar_url,u.header_url,u.custom_css,u.local,u.ap_id,u.inbox_url,u.created_at,u.updated_at
+             FROM users u JOIN follows f ON f.following_id=u.id
+             WHERE f.follower_id=$1 AND f.state='accepted'
+             ORDER BY f.created_at DESC LIMIT $2 OFFSET $3"
+        )
+        .bind(user_id.as_uuid())
+        .bind(page.limit())
+        .bind(page.offset())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(Paginated {
+            items: rows.into_iter().map(User::from).collect(),
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+
+    async fn get_accepted_following_ids(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Vec<UserId>, DomainError> {
+        let ids: Vec<uuid::Uuid> = sqlx::query_scalar(
+            "SELECT following_id FROM follows WHERE follower_id=$1 AND state='accepted'",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+        Ok(ids.into_iter().map(UserId::from_uuid).collect())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::seed_user;
+    use chrono::Utc;
+    use domain::value_objects::*;
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn save_and_find_follow(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgFollowRepository::new(pool);
+        let follow = Follow {
+            follower_id: alice.id.clone(),
+            following_id: bob.id.clone(),
+            state: FollowState::Accepted,
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&follow).await.unwrap();
+        let found = repo.find(&alice.id, &bob.id).await.unwrap().unwrap();
+        assert_eq!(found.state, FollowState::Accepted);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn update_state(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgFollowRepository::new(pool);
+        let follow = Follow {
+            follower_id: alice.id.clone(),
+            following_id: bob.id.clone(),
+            state: FollowState::Pending,
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&follow).await.unwrap();
+        repo.update_state(&alice.id, &bob.id, &FollowState::Accepted)
+            .await
+            .unwrap();
+        let found = repo.find(&alice.id, &bob.id).await.unwrap().unwrap();
+        assert_eq!(found.state, FollowState::Accepted);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn get_accepted_following_ids(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgFollowRepository::new(pool);
+        let follow = Follow {
+            follower_id: alice.id.clone(),
+            following_id: bob.id.clone(),
+            state: FollowState::Accepted,
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&follow).await.unwrap();
+        let ids = repo.get_accepted_following_ids(&alice.id).await.unwrap();
+        assert_eq!(ids, vec![bob.id]);
+    }
+}

crates/adapters/postgres/src/lib.rs

@@ -0,0 +1,20 @@
+pub mod activitypub;
+pub mod engagement;
+pub mod api_key;
+pub mod block;
+pub mod boost;
+mod db_error;
+pub mod failed_event;
+pub mod outbox;
+pub mod feed;
+pub mod follow;
+pub mod like;
+pub mod notification;
+pub mod remote_actor;
+pub mod remote_actor_connections;
+pub mod tag;
+#[cfg(test)]
+pub(crate) mod test_helpers;
+pub mod thought;
+pub mod top_friend;
+pub mod user;

crates/adapters/postgres/src/like.rs

@@ -0,0 +1,110 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use domain::{
+    errors::DomainError,
+    models::social::Like,
+    ports::LikeRepository,
+    value_objects::{LikeId, ThoughtId, UserId},
+};
+use sqlx::PgPool;
+
+pub struct PgLikeRepository {
+    pool: PgPool,
+}
+impl PgLikeRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl LikeRepository for PgLikeRepository {
+    async fn save(&self, l: &Like) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO likes(id,user_id,thought_id,ap_id,created_at) VALUES($1,$2,$3,$4,$5) ON CONFLICT(user_id,thought_id) DO NOTHING"
+        )
+        .bind(l.id.as_uuid()).bind(l.user_id.as_uuid()).bind(l.thought_id.as_uuid()).bind(&l.ap_id).bind(l.created_at)
+        .execute(&self.pool).await.into_domain().map(|_| ())
+    }
+
+    async fn delete(&self, user_id: &UserId, thought_id: &ThoughtId) -> Result<(), DomainError> {
+        let r = sqlx::query("DELETE FROM likes WHERE user_id=$1 AND thought_id=$2")
+            .bind(user_id.as_uuid())
+            .bind(thought_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()?;
+        if r.rows_affected() == 0 {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+
+    async fn find(
+        &self,
+        user_id: &UserId,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<Like>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            user_id: uuid::Uuid,
+            thought_id: uuid::Uuid,
+            ap_id: Option<String>,
+            created_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>("SELECT id,user_id,thought_id,ap_id,created_at FROM likes WHERE user_id=$1 AND thought_id=$2")
+            .bind(user_id.as_uuid()).bind(thought_id.as_uuid())
+            .fetch_optional(&self.pool).await
+            .into_domain()
+            .map(|o| o.map(|r| Like { id: LikeId::from_uuid(r.id), user_id: UserId::from_uuid(r.user_id), thought_id: ThoughtId::from_uuid(r.thought_id), ap_id: r.ap_id, created_at: r.created_at }))
+    }
+
+    async fn count_for_thought(&self, thought_id: &ThoughtId) -> Result<i64, DomainError> {
+        sqlx::query_scalar("SELECT COUNT(*) FROM likes WHERE thought_id=$1")
+            .bind(thought_id.as_uuid())
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::seed_user_and_thought;
+    use chrono::Utc;
+    use domain::value_objects::*;
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn like_and_count(pool: sqlx::PgPool) {
+        let (user, thought) = seed_user_and_thought(&pool).await;
+        let repo = PgLikeRepository::new(pool);
+        let like = Like {
+            id: LikeId::new(),
+            user_id: user.id.clone(),
+            thought_id: thought.id.clone(),
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&like).await.unwrap();
+        assert_eq!(repo.count_for_thought(&thought.id).await.unwrap(), 1);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn unlike(pool: sqlx::PgPool) {
+        let (user, thought) = seed_user_and_thought(&pool).await;
+        let repo = PgLikeRepository::new(pool);
+        let like = Like {
+            id: LikeId::new(),
+            user_id: user.id.clone(),
+            thought_id: thought.id.clone(),
+            ap_id: None,
+            created_at: Utc::now(),
+        };
+        repo.save(&like).await.unwrap();
+        repo.delete(&user.id, &thought.id).await.unwrap();
+        assert_eq!(repo.count_for_thought(&thought.id).await.unwrap(), 0);
+    }
+}

crates/adapters/postgres/src/notification.rs

@@ -0,0 +1,230 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{PageParams, Paginated},
+        notification::{Notification, NotificationKind},
+    },
+    ports::NotificationRepository,
+    value_objects::{NotificationId, ThoughtId, UserId},
+};
+use sqlx::PgPool;
+
+pub struct PgNotificationRepository {
+    pool: PgPool,
+}
+impl PgNotificationRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[derive(sqlx::FromRow)]
+struct NotificationRow {
+    id: uuid::Uuid,
+    user_id: uuid::Uuid,
+    notification_type: String,
+    from_user_id: Option<uuid::Uuid>,
+    thought_id: Option<uuid::Uuid>,
+    read: bool,
+    created_at: DateTime<Utc>,
+}
+
+fn row_to_notification(r: NotificationRow) -> Result<Notification, DomainError> {
+    let from_user_id = r
+        .from_user_id
+        .map(UserId::from_uuid)
+        .ok_or_else(|| DomainError::Internal("notification missing from_user_id".into()))?;
+
+    let kind = match r.notification_type.as_str() {
+        "follow" => NotificationKind::Follow { from_user_id },
+        other => {
+            let thought_id = r.thought_id.map(ThoughtId::from_uuid).ok_or_else(|| {
+                DomainError::Internal(format!("notification type '{other}' missing thought_id"))
+            })?;
+            match other {
+                "like" => NotificationKind::Like {
+                    thought_id,
+                    from_user_id,
+                },
+                "boost" => NotificationKind::Boost {
+                    thought_id,
+                    from_user_id,
+                },
+                "reply" => NotificationKind::Reply {
+                    thought_id,
+                    from_user_id,
+                },
+                "mention" => NotificationKind::Mention {
+                    thought_id,
+                    from_user_id,
+                },
+                _ => {
+                    return Err(DomainError::Internal(format!(
+                        "unknown notification type: {other}"
+                    )))
+                }
+            }
+        }
+    };
+
+    Ok(Notification {
+        id: NotificationId::from_uuid(r.id),
+        user_id: UserId::from_uuid(r.user_id),
+        kind,
+        read: r.read,
+        created_at: r.created_at,
+    })
+}
+
+#[async_trait]
+impl NotificationRepository for PgNotificationRepository {
+    async fn save(&self, n: &Notification) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO notifications(id,user_id,notification_type,from_user_id,thought_id,read,created_at)
+             VALUES($1,$2,$3,$4,$5,$6,$7)
+             ON CONFLICT(id) DO NOTHING"
+        )
+        .bind(n.id.as_uuid())
+        .bind(n.user_id.as_uuid())
+        .bind(n.kind.kind_str())
+        .bind(n.kind.from_user_id().as_uuid())
+        .bind(n.kind.thought_id().map(|t| t.as_uuid()))
+        .bind(n.read)
+        .bind(n.created_at)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn list_for_user(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<Notification>, DomainError> {
+        let total: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM notifications WHERE user_id=$1")
+            .bind(user_id.as_uuid())
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()?;
+        let rows = sqlx::query_as::<_, NotificationRow>(
+            "SELECT id,user_id,notification_type,from_user_id,thought_id,read,created_at FROM notifications WHERE user_id=$1 ORDER BY created_at DESC LIMIT $2 OFFSET $3"
+        ).bind(user_id.as_uuid()).bind(page.limit()).bind(page.offset())
+        .fetch_all(&self.pool).await.into_domain()?;
+        let items = rows
+            .into_iter()
+            .map(row_to_notification)
+            .collect::<Result<Vec<_>, _>>()?;
+        Ok(Paginated {
+            items,
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+
+    async fn count_unread(&self, user_id: &UserId) -> Result<u64, DomainError> {
+        let count: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM notifications WHERE user_id=$1 AND read=false",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_one(&self.pool)
+        .await
+        .into_domain()?;
+        Ok(count as u64)
+    }
+
+    async fn mark_read(&self, id: &NotificationId, user_id: &UserId) -> Result<(), DomainError> {
+        sqlx::query("UPDATE notifications SET read=true WHERE id=$1 AND user_id=$2")
+            .bind(id.as_uuid())
+            .bind(user_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+
+    async fn mark_all_read(&self, user_id: &UserId) -> Result<(), DomainError> {
+        sqlx::query("UPDATE notifications SET read=true WHERE user_id=$1")
+            .bind(user_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers;
+    use chrono::Utc;
+    use domain::{
+        models::{notification::NotificationKind, user::User},
+        value_objects::*,
+    };
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn save_and_list(pool: sqlx::PgPool) {
+        let user = test_helpers::seed_user(&pool, "alice", "alice@ex.com").await;
+        let from_user = test_helpers::seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgNotificationRepository::new(pool);
+        use domain::models::feed::PageParams;
+        let n = Notification {
+            id: NotificationId::new(),
+            user_id: user.id.clone(),
+            kind: NotificationKind::Follow {
+                from_user_id: from_user.id.clone(),
+            },
+            read: false,
+            created_at: Utc::now(),
+        };
+        repo.save(&n).await.unwrap();
+        let page = repo
+            .list_for_user(
+                &user.id,
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+            )
+            .await
+            .unwrap();
+        assert_eq!(page.total, 1);
+        assert!(!page.items[0].read);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn mark_all_read(pool: sqlx::PgPool) {
+        let user = test_helpers::seed_user(&pool, "alice", "alice@ex.com").await;
+        let from_user = test_helpers::seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgNotificationRepository::new(pool);
+        use domain::models::feed::PageParams;
+        let n = Notification {
+            id: NotificationId::new(),
+            user_id: user.id.clone(),
+            kind: NotificationKind::Follow {
+                from_user_id: from_user.id.clone(),
+            },
+            read: false,
+            created_at: Utc::now(),
+        };
+        repo.save(&n).await.unwrap();
+        repo.mark_all_read(&user.id).await.unwrap();
+        let page = repo
+            .list_for_user(
+                &user.id,
+                &PageParams {
+                    page: 1,
+                    per_page: 20,
+                },
+            )
+            .await
+            .unwrap();
+        assert!(page.items[0].read);
+    }
+}

crates/adapters/postgres/src/outbox.rs

@@ -0,0 +1,61 @@
+use async_trait::async_trait;
+use domain::{errors::DomainError, events::DomainEvent, ports::OutboxWriter};
+use event_payload::EventPayload;
+use sqlx::PgPool;
+use uuid::Uuid;
+
+pub struct PgOutboxWriter {
+    pool: PgPool,
+}
+
+impl PgOutboxWriter {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+/// Primary aggregate UUID for an event — used to populate `aggregate_id`.
+fn aggregate_id(event: &DomainEvent) -> Uuid {
+    match event {
+        DomainEvent::ThoughtCreated { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::ThoughtDeleted { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::ThoughtUpdated { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::LikeAdded { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::LikeRemoved { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::BoostAdded { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::BoostRemoved { thought_id, .. } => thought_id.as_uuid(),
+        DomainEvent::FollowRequested { follower_id, .. } => follower_id.as_uuid(),
+        DomainEvent::FollowAccepted { follower_id, .. } => follower_id.as_uuid(),
+        DomainEvent::FollowRejected { follower_id, .. } => follower_id.as_uuid(),
+        DomainEvent::Unfollowed { follower_id, .. } => follower_id.as_uuid(),
+        DomainEvent::UserBlocked { blocker_id, .. } => blocker_id.as_uuid(),
+        DomainEvent::UserUnblocked { blocker_id, .. } => blocker_id.as_uuid(),
+        DomainEvent::UserRegistered { user_id } => user_id.as_uuid(),
+        DomainEvent::ProfileUpdated { user_id } => user_id.as_uuid(),
+        DomainEvent::MentionReceived { thought_id, .. } => thought_id.as_uuid(),
+    }
+}
+
+#[async_trait]
+impl OutboxWriter for PgOutboxWriter {
+    async fn append(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        let payload = EventPayload::from(event);
+        let event_type = payload.subject();
+        let payload_json =
+            serde_json::to_value(&payload).map_err(|e| DomainError::Internal(e.to_string()))?;
+        let agg_id = aggregate_id(event);
+
+        sqlx::query(
+            "INSERT INTO outbox_events (aggregate_id, event_type, payload) \
+             VALUES ($1, $2, $3)",
+        )
+        .bind(agg_id)
+        .bind(event_type)
+        .bind(payload_json)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        Ok(())
+    }
+}

crates/adapters/postgres/src/remote_actor.rs

@@ -0,0 +1,59 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use domain::{
+    errors::DomainError, models::remote_actor::RemoteActor, ports::RemoteActorRepository,
+};
+use sqlx::PgPool;
+
+pub struct PgRemoteActorRepository {
+    pool: PgPool,
+}
+impl PgRemoteActorRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl RemoteActorRepository for PgRemoteActorRepository {
+    async fn upsert(&self, a: &RemoteActor) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO remote_actors(url,handle,display_name,avatar_url,last_fetched_at)
+             VALUES($1,$2,$3,$4,$5)
+             ON CONFLICT(url) DO UPDATE SET handle=EXCLUDED.handle,display_name=EXCLUDED.display_name,
+             avatar_url=EXCLUDED.avatar_url,last_fetched_at=EXCLUDED.last_fetched_at"
+        )
+        .bind(&a.url).bind(&a.handle).bind(&a.display_name).bind(&a.avatar_url).bind(a.last_fetched_at)
+        .execute(&self.pool).await.into_domain().map(|_| ())
+    }
+
+    async fn find_by_url(&self, url: &str) -> Result<Option<RemoteActor>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            url: String,
+            handle: String,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            last_fetched_at: DateTime<Utc>,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT url,handle,display_name,avatar_url,last_fetched_at FROM remote_actors WHERE url=$1"
+        ).bind(url).fetch_optional(&self.pool).await
+        .into_domain()
+        .map(|o| o.map(|r| RemoteActor {
+            url: r.url,
+            handle: r.handle,
+            display_name: r.display_name,
+            avatar_url: r.avatar_url,
+            last_fetched_at: r.last_fetched_at,
+            bio: None,
+            banner_url: None,
+            also_known_as: None,
+            outbox_url: None,
+            followers_url: None,
+            following_url: None,
+            attachment: vec![],
+        }))
+    }
+}

crates/adapters/postgres/src/remote_actor_connections.rs

@@ -0,0 +1,111 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError, models::actor_connection_summary::ActorConnectionSummary,
+    ports::RemoteActorConnectionRepository,
+};
+use sqlx::PgPool;
+
+pub struct PgRemoteActorConnectionRepository {
+    pool: PgPool,
+}
+
+impl PgRemoteActorConnectionRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl RemoteActorConnectionRepository for PgRemoteActorConnectionRepository {
+    async fn upsert_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+        actors: &[ActorConnectionSummary],
+    ) -> Result<(), DomainError> {
+        for actor in actors {
+            sqlx::query(
+                "INSERT INTO remote_actor_connections
+                    (actor_url, connection_type, page, connected_actor_url,
+                     connected_handle, connected_display_name, connected_avatar_url, fetched_at)
+                 VALUES ($1, $2, $3, $4, $5, $6, $7, NOW())
+                 ON CONFLICT(actor_url, connection_type, page, connected_actor_url)
+                 DO UPDATE SET
+                     connected_handle       = EXCLUDED.connected_handle,
+                     connected_display_name = EXCLUDED.connected_display_name,
+                     connected_avatar_url   = EXCLUDED.connected_avatar_url,
+                     fetched_at             = NOW()",
+            )
+            .bind(actor_url)
+            .bind(connection_type)
+            .bind(page as i32)
+            .bind(&actor.url)
+            .bind(&actor.handle)
+            .bind(&actor.display_name)
+            .bind(&actor.avatar_url)
+            .execute(&self.pool)
+            .await
+            .into_domain()?;
+        }
+        Ok(())
+    }
+
+    async fn list_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Vec<ActorConnectionSummary>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            connected_actor_url: String,
+            connected_handle: String,
+            connected_display_name: Option<String>,
+            connected_avatar_url: Option<String>,
+        }
+        let rows = sqlx::query_as::<_, Row>(
+            "SELECT connected_actor_url, connected_handle, connected_display_name, connected_avatar_url
+             FROM remote_actor_connections
+             WHERE actor_url = $1 AND connection_type = $2 AND page = $3
+             ORDER BY connected_handle",
+        )
+        .bind(actor_url)
+        .bind(connection_type)
+        .bind(page as i32)
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(rows
+            .into_iter()
+            .map(|r| ActorConnectionSummary {
+                url: r.connected_actor_url,
+                handle: r.connected_handle,
+                display_name: r.connected_display_name,
+                avatar_url: r.connected_avatar_url,
+            })
+            .collect())
+    }
+
+    async fn connection_page_age(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError> {
+        let row: Option<(Option<chrono::DateTime<chrono::Utc>>,)> = sqlx::query_as(
+            "SELECT MAX(fetched_at) FROM remote_actor_connections
+             WHERE actor_url = $1 AND connection_type = $2 AND page = $3",
+        )
+        .bind(actor_url)
+        .bind(connection_type)
+        .bind(page as i32)
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(row.and_then(|(ts,)| ts))
+    }
+}

crates/adapters/postgres/src/tag.rs

@@ -0,0 +1,184 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{PageParams, Paginated},
+        tag::Tag,
+        thought::Thought,
+    },
+    ports::TagRepository,
+    value_objects::ThoughtId,
+};
+use sqlx::PgPool;
+
+pub struct PgTagRepository {
+    pool: PgPool,
+}
+impl PgTagRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl TagRepository for PgTagRepository {
+    async fn find_or_create(&self, name: &str) -> Result<Tag, DomainError> {
+        let name = name.to_lowercase();
+        sqlx::query("INSERT INTO tags(name) VALUES($1) ON CONFLICT(name) DO NOTHING")
+            .bind(&name)
+            .execute(&self.pool)
+            .await
+            .into_domain()?;
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: i32,
+            name: String,
+        }
+        let row = sqlx::query_as::<_, Row>("SELECT id,name FROM tags WHERE name=$1")
+            .bind(&name)
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()?;
+        Ok(Tag {
+            id: row.id,
+            name: row.name,
+        })
+    }
+
+    async fn attach_to_thought(
+        &self,
+        thought_id: &ThoughtId,
+        tag_id: i32,
+    ) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO thought_tags(thought_id,tag_id) VALUES($1,$2) ON CONFLICT DO NOTHING",
+        )
+        .bind(thought_id.as_uuid())
+        .bind(tag_id)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn detach_from_thought(&self, thought_id: &ThoughtId) -> Result<(), DomainError> {
+        sqlx::query("DELETE FROM thought_tags WHERE thought_id=$1")
+            .bind(thought_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+
+    async fn list_for_thought(&self, thought_id: &ThoughtId) -> Result<Vec<Tag>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: i32,
+            name: String,
+        }
+        sqlx::query_as::<_, Row>(
+            "SELECT t.id,t.name FROM tags t JOIN thought_tags tt ON tt.tag_id=t.id WHERE tt.thought_id=$1"
+        ).bind(thought_id.as_uuid()).fetch_all(&self.pool).await
+        .into_domain()
+        .map(|rows| rows.into_iter().map(|r| Tag { id: r.id, name: r.name }).collect())
+    }
+
+    async fn list_thoughts_by_tag(
+        &self,
+        tag_name: &str,
+        page: &PageParams,
+    ) -> Result<Paginated<Thought>, DomainError> {
+        let total: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM thought_tags tt JOIN tags t ON t.id=tt.tag_id WHERE t.name=$1",
+        )
+        .bind(tag_name)
+        .fetch_one(&self.pool)
+        .await
+        .into_domain()?;
+
+        let rows = sqlx::query_as::<_, crate::thought::ThoughtRow>(
+            "SELECT th.id,th.user_id,th.content,th.in_reply_to_id,th.in_reply_to_url,th.ap_id,th.visibility,th.content_warning,th.sensitive,th.local,th.created_at,th.updated_at
+             FROM thoughts th JOIN thought_tags tt ON tt.thought_id=th.id JOIN tags t ON t.id=tt.tag_id
+             WHERE t.name=$1 ORDER BY th.created_at DESC LIMIT $2 OFFSET $3"
+        ).bind(tag_name).bind(page.limit()).bind(page.offset())
+        .fetch_all(&self.pool).await.into_domain()?;
+
+        Ok(Paginated {
+            items: rows
+                .into_iter()
+                .map(Thought::try_from)
+                .collect::<Result<Vec<_>, _>>()?,
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+
+    async fn popular_tags(&self, limit: usize) -> Result<Vec<(String, i64)>, DomainError> {
+        sqlx::query_as::<_, (String, i64)>(
+            "SELECT t.name, COUNT(tt.thought_id) AS thought_count
+             FROM tags t
+             JOIN thought_tags tt ON t.id = tt.tag_id
+             GROUP BY t.id, t.name
+             ORDER BY thought_count DESC
+             LIMIT $1",
+        )
+        .bind(limit as i64)
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{thought::PgThoughtRepository, user::PgUserRepository};
+    use domain::ports::{ThoughtRepository, UserWriter};
+    use domain::{
+        models::{
+            thought::{Thought, Visibility},
+            user::User,
+        },
+        value_objects::*,
+    };
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn find_or_create_tag(pool: sqlx::PgPool) {
+        let repo = PgTagRepository::new(pool);
+        let t1 = repo.find_or_create("rust").await.unwrap();
+        let t2 = repo.find_or_create("rust").await.unwrap();
+        assert_eq!(t1.id, t2.id);
+        assert_eq!(t1.name, "rust");
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn attach_and_list(pool: sqlx::PgPool) {
+        let urepo = PgUserRepository::new(pool.clone());
+        let trepo = PgThoughtRepository::new(pool.clone());
+        let u = User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        );
+        urepo.save(&u).await.unwrap();
+        let t = Thought::new_local(
+            ThoughtId::new(),
+            u.id.clone(),
+            Content::new_local("hi").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        trepo.save(&t).await.unwrap();
+        let repo = PgTagRepository::new(pool);
+        let tag = repo.find_or_create("greetings").await.unwrap();
+        repo.attach_to_thought(&t.id, tag.id).await.unwrap();
+        let tags = repo.list_for_thought(&t.id).await.unwrap();
+        assert_eq!(tags.len(), 1);
+        assert_eq!(tags[0].name, "greetings");
+    }
+}

crates/adapters/postgres/src/test_helpers.rs

@@ -0,0 +1,37 @@
+use crate::{thought::PgThoughtRepository, user::PgUserRepository};
+use domain::{
+    models::{
+        thought::{Thought, Visibility},
+        user::User,
+    },
+    ports::{ThoughtRepository, UserWriter},
+    value_objects::{Content, Email, PasswordHash, ThoughtId, UserId, Username},
+};
+
+pub async fn seed_user(pool: &sqlx::PgPool, username: &str, email: &str) -> User {
+    let repo = PgUserRepository::new(pool.clone());
+    let u = User::new_local(
+        UserId::new(),
+        Username::new(username).unwrap(),
+        Email::new(email).unwrap(),
+        PasswordHash("h".into()),
+    );
+    repo.save(&u).await.unwrap();
+    u
+}
+
+pub async fn seed_user_and_thought(pool: &sqlx::PgPool) -> (User, Thought) {
+    let user = seed_user(pool, "alice", "alice@ex.com").await;
+    let trepo = PgThoughtRepository::new(pool.clone());
+    let t = Thought::new_local(
+        ThoughtId::new(),
+        user.id.clone(),
+        Content::new_local("hi").unwrap(),
+        None,
+        Visibility::Public,
+        None,
+        false,
+    );
+    trepo.save(&t).await.unwrap();
+    (user, t)
+}

crates/adapters/postgres/src/thought.rs

@@ -0,0 +1,262 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+
+use domain::{
+    errors::DomainError,
+    models::{
+        feed::{PageParams, Paginated},
+        thought::{Thought, Visibility},
+    },
+    ports::ThoughtRepository,
+    value_objects::{Content, ThoughtId, UserId},
+};
+use sqlx::PgPool;
+
+pub struct PgThoughtRepository {
+    pool: PgPool,
+}
+impl PgThoughtRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[derive(sqlx::FromRow)]
+pub(crate) struct ThoughtRow {
+    pub id: uuid::Uuid,
+    pub user_id: uuid::Uuid,
+    pub content: String,
+    pub in_reply_to_id: Option<uuid::Uuid>,
+    pub visibility: String,
+    pub content_warning: Option<String>,
+    pub sensitive: bool,
+    pub local: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: Option<DateTime<Utc>>,
+}
+
+impl TryFrom<ThoughtRow> for Thought {
+    type Error = DomainError;
+    fn try_from(r: ThoughtRow) -> Result<Self, DomainError> {
+        Ok(Thought {
+            id: ThoughtId::from_uuid(r.id),
+            user_id: UserId::from_uuid(r.user_id),
+            content: Content::new_remote(r.content),
+            in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
+            visibility: Visibility::from_db_str(&r.visibility)?,
+            content_warning: r.content_warning,
+            sensitive: r.sensitive,
+            local: r.local,
+            created_at: r.created_at,
+            updated_at: r.updated_at,
+        })
+    }
+}
+
+const THOUGHT_SELECT: &str =
+    "SELECT id,user_id,content,in_reply_to_id,visibility,content_warning,sensitive,local,created_at,updated_at FROM thoughts";
+
+#[async_trait]
+impl ThoughtRepository for PgThoughtRepository {
+    async fn save(&self, t: &Thought) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO thoughts(id,user_id,content,in_reply_to_id,visibility,content_warning,sensitive,local,created_at)
+             VALUES($1,$2,$3,$4,$5,$6,$7,$8,$9)
+             ON CONFLICT(id) DO UPDATE SET content=EXCLUDED.content,updated_at=NOW()"
+        )
+        .bind(t.id.as_uuid())
+        .bind(t.user_id.as_uuid())
+        .bind(t.content.as_str())
+        .bind(t.in_reply_to_id.as_ref().map(|x| x.as_uuid()))
+        .bind(t.visibility.as_str())
+        .bind(&t.content_warning)
+        .bind(t.sensitive)
+        .bind(t.local)
+        .bind(t.created_at)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+
+    async fn find_by_id(&self, id: &ThoughtId) -> Result<Option<Thought>, DomainError> {
+        sqlx::query_as::<_, ThoughtRow>(&format!("{THOUGHT_SELECT} WHERE id=$1"))
+            .bind(id.as_uuid())
+            .fetch_optional(&self.pool)
+            .await
+            .into_domain()
+            .and_then(|o| o.map(Thought::try_from).transpose())
+    }
+
+    async fn delete(&self, id: &ThoughtId, user_id: &UserId) -> Result<(), DomainError> {
+        let r = sqlx::query("DELETE FROM thoughts WHERE id=$1 AND user_id=$2")
+            .bind(id.as_uuid())
+            .bind(user_id.as_uuid())
+            .execute(&self.pool)
+            .await
+            .into_domain()?;
+        if r.rows_affected() == 0 {
+            return Err(DomainError::NotFound);
+        }
+        Ok(())
+    }
+
+    async fn update_content(&self, id: &ThoughtId, content: &Content) -> Result<(), DomainError> {
+        sqlx::query("UPDATE thoughts SET content=$2,updated_at=NOW() WHERE id=$1")
+            .bind(id.as_uuid())
+            .bind(content.as_str())
+            .execute(&self.pool)
+            .await
+            .into_domain()
+            .map(|_| ())
+    }
+
+    async fn get_thread(&self, id: &ThoughtId) -> Result<Vec<Thought>, DomainError> {
+        // Recursive CTE: fetches the root thought and all nested replies at any depth.
+        sqlx::query_as::<_, ThoughtRow>(
+            "WITH RECURSIVE thread AS (
+                SELECT id,user_id,content,in_reply_to_id,
+                       visibility,content_warning,sensitive,local,created_at,updated_at
+                FROM thoughts WHERE id = $1
+                UNION ALL
+                SELECT t.id,t.user_id,t.content,t.in_reply_to_id,
+                       t.visibility,t.content_warning,t.sensitive,t.local,t.created_at,t.updated_at
+                FROM thoughts t JOIN thread ON t.in_reply_to_id = thread.id
+            )
+            SELECT * FROM thread ORDER BY created_at ASC",
+        )
+        .bind(id.as_uuid())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()
+        .and_then(|rows| rows.into_iter().map(Thought::try_from).collect())
+    }
+
+    async fn list_by_user(
+        &self,
+        user_id: &UserId,
+        page: &PageParams,
+    ) -> Result<Paginated<Thought>, DomainError> {
+        let uid = user_id.as_uuid();
+        let total: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM thoughts WHERE user_id = $1")
+            .bind(uid)
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()?;
+
+        let rows = sqlx::query_as::<_, ThoughtRow>(&format!(
+            "{THOUGHT_SELECT} WHERE user_id=$1 ORDER BY created_at DESC LIMIT $2 OFFSET $3"
+        ))
+        .bind(uid)
+        .bind(page.limit())
+        .bind(page.offset())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(Paginated {
+            items: rows
+                .into_iter()
+                .map(Thought::try_from)
+                .collect::<Result<Vec<_>, _>>()?,
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::seed_user;
+    use domain::{
+        models::thought::{Thought, Visibility},
+        value_objects::*,
+    };
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn save_and_find_thought(pool: sqlx::PgPool) {
+        let user = seed_user(&pool, "alice", "alice@ex.com").await;
+        let repo = PgThoughtRepository::new(pool);
+        let t = Thought::new_local(
+            ThoughtId::new(),
+            user.id.clone(),
+            Content::new_local("hello world").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        repo.save(&t).await.unwrap();
+        let found = repo.find_by_id(&t.id).await.unwrap().unwrap();
+        assert_eq!(found.content.as_str(), "hello world");
+        assert!(found.local);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_thought(pool: sqlx::PgPool) {
+        let user = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgThoughtRepository::new(pool);
+        let t = Thought::new_local(
+            ThoughtId::new(),
+            user.id.clone(),
+            Content::new_local("bye").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        repo.save(&t).await.unwrap();
+        repo.delete(&t.id, &user.id).await.unwrap();
+        assert!(repo.find_by_id(&t.id).await.unwrap().is_none());
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_wrong_owner_returns_not_found(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgThoughtRepository::new(pool);
+        let t = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("secret").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        repo.save(&t).await.unwrap();
+        let err = repo.delete(&t.id, &bob.id).await.unwrap_err();
+        assert!(matches!(err, DomainError::NotFound));
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn get_thread_returns_root_and_replies(pool: sqlx::PgPool) {
+        let user = seed_user(&pool, "charlie", "charlie@ex.com").await;
+        let repo = PgThoughtRepository::new(pool);
+        let root = Thought::new_local(
+            ThoughtId::new(),
+            user.id.clone(),
+            Content::new_local("root").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        let reply = Thought::new_local(
+            ThoughtId::new(),
+            user.id.clone(),
+            Content::new_local("reply").unwrap(),
+            Some(root.id.clone()),
+            Visibility::Public,
+            None,
+            false,
+        );
+        repo.save(&root).await.unwrap();
+        repo.save(&reply).await.unwrap();
+        let thread = repo.get_thread(&root.id).await.unwrap();
+        assert_eq!(thread.len(), 2);
+    }
+}

crates/adapters/postgres/src/top_friend.rs

@@ -0,0 +1,155 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    models::{top_friend::TopFriend, user::User},
+    ports::TopFriendRepository,
+    value_objects::UserId,
+};
+use sqlx::PgPool;
+
+pub struct PgTopFriendRepository {
+    pool: PgPool,
+}
+impl PgTopFriendRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl TopFriendRepository for PgTopFriendRepository {
+    async fn set_top_friends(
+        &self,
+        user_id: &UserId,
+        friends: Vec<(UserId, i16)>,
+    ) -> Result<(), DomainError> {
+        let mut tx = self.pool.begin().await.into_domain()?;
+        sqlx::query("DELETE FROM top_friends WHERE user_id=$1")
+            .bind(user_id.as_uuid())
+            .execute(&mut *tx)
+            .await
+            .into_domain()?;
+        for (friend_id, pos) in friends {
+            sqlx::query("INSERT INTO top_friends(user_id,friend_id,position) VALUES($1,$2,$3)")
+                .bind(user_id.as_uuid())
+                .bind(friend_id.as_uuid())
+                .bind(pos)
+                .execute(&mut *tx)
+                .await
+                .into_domain()?;
+        }
+        tx.commit().await.into_domain()
+    }
+
+    async fn list_for_user(&self, user_id: &UserId) -> Result<Vec<(TopFriend, User)>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            tf_user_id: uuid::Uuid,
+            friend_id: uuid::Uuid,
+            position: i16,
+            id: uuid::Uuid,
+            username: String,
+            email: String,
+            password_hash: String,
+            display_name: Option<String>,
+            bio: Option<String>,
+            avatar_url: Option<String>,
+            header_url: Option<String>,
+            custom_css: Option<String>,
+            local: bool,
+            created_at: chrono::DateTime<chrono::Utc>,
+            updated_at: chrono::DateTime<chrono::Utc>,
+        }
+        let rows = sqlx::query_as::<_, Row>(
+            "SELECT tf.user_id AS tf_user_id, tf.friend_id, tf.position,
+             u.id, u.username, u.email, u.password_hash, u.display_name, u.bio,
+             u.avatar_url, u.header_url, u.custom_css, u.local,
+             u.created_at, u.updated_at
+             FROM top_friends tf JOIN users u ON u.id=tf.friend_id
+             WHERE tf.user_id=$1 ORDER BY tf.position",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(rows
+            .into_iter()
+            .map(|r| {
+                use domain::value_objects::{Email, PasswordHash, Username};
+                let tf = TopFriend {
+                    user_id: UserId::from_uuid(r.tf_user_id),
+                    friend_id: UserId::from_uuid(r.friend_id),
+                    position: r.position,
+                };
+                let u = User {
+                    id: UserId::from_uuid(r.id),
+                    username: Username::from_trusted(r.username),
+                    email: Email::from_trusted(r.email),
+                    password_hash: PasswordHash(r.password_hash),
+                    display_name: r.display_name,
+                    bio: r.bio,
+                    avatar_url: r.avatar_url,
+                    header_url: r.header_url,
+                    custom_css: r.custom_css,
+                    local: r.local,
+                    created_at: r.created_at,
+                    updated_at: r.updated_at,
+                };
+                (tf, u)
+            })
+            .collect())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::user::PgUserRepository;
+    use domain::ports::UserWriter;
+    use domain::{models::user::User, value_objects::*};
+
+    async fn seed_user(pool: &sqlx::PgPool, username: &str, email: &str) -> User {
+        let repo = PgUserRepository::new(pool.clone());
+        let u = User::new_local(
+            UserId::new(),
+            Username::new(username).unwrap(),
+            Email::new(email).unwrap(),
+            PasswordHash("h".into()),
+        );
+        repo.save(&u).await.unwrap();
+        u
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn set_and_list_top_friends(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let repo = PgTopFriendRepository::new(pool);
+        repo.set_top_friends(&alice.id, vec![(bob.id.clone(), 1)])
+            .await
+            .unwrap();
+        let friends = repo.list_for_user(&alice.id).await.unwrap();
+        assert_eq!(friends.len(), 1);
+        assert_eq!(friends[0].0.position, 1);
+        assert_eq!(friends[0].1.username.as_str(), "bob");
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn replace_top_friends(pool: sqlx::PgPool) {
+        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
+        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
+        let carol = seed_user(&pool, "carol", "carol@ex.com").await;
+        let repo = PgTopFriendRepository::new(pool);
+        repo.set_top_friends(&alice.id, vec![(bob.id.clone(), 1)])
+            .await
+            .unwrap();
+        repo.set_top_friends(&alice.id, vec![(carol.id.clone(), 1)])
+            .await
+            .unwrap();
+        let friends = repo.list_for_user(&alice.id).await.unwrap();
+        assert_eq!(friends.len(), 1);
+        assert_eq!(friends[0].1.username.as_str(), "carol");
+    }
+}

crates/adapters/postgres/src/user.rs

@@ -0,0 +1,352 @@
+use crate::db_error::IntoDbResult;
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use domain::{
+    errors::DomainError,
+    models::feed::{PageParams, Paginated, UserSummary},
+    models::user::User,
+    ports::{UserReader, UserWriter},
+    value_objects::{Email, PasswordHash, UserId, Username},
+};
+use sqlx::PgPool;
+use std::collections::HashMap;
+
+pub struct PgUserRepository {
+    pool: PgPool,
+}
+impl PgUserRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[derive(sqlx::FromRow)]
+pub struct UserRow {
+    pub id: uuid::Uuid,
+    pub username: String,
+    pub email: String,
+    pub password_hash: String,
+    pub display_name: Option<String>,
+    pub bio: Option<String>,
+    pub avatar_url: Option<String>,
+    pub header_url: Option<String>,
+    pub custom_css: Option<String>,
+    pub local: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: DateTime<Utc>,
+}
+
+impl From<UserRow> for User {
+    fn from(r: UserRow) -> Self {
+        User {
+            id: UserId::from_uuid(r.id),
+            username: Username::from_trusted(r.username),
+            email: Email::from_trusted(r.email),
+            password_hash: PasswordHash(r.password_hash),
+            display_name: r.display_name,
+            bio: r.bio,
+            avatar_url: r.avatar_url,
+            header_url: r.header_url,
+            custom_css: r.custom_css,
+            local: r.local,
+            created_at: r.created_at,
+            updated_at: r.updated_at,
+        }
+    }
+}
+
+pub const USER_SELECT: &str =
+    "SELECT id,username,email,password_hash,display_name,bio,avatar_url,header_url,\
+     custom_css,local,created_at,updated_at FROM users";
+
+#[async_trait]
+impl UserReader for PgUserRepository {
+    async fn find_by_id(&self, id: &UserId) -> Result<Option<User>, DomainError> {
+        sqlx::query_as::<_, UserRow>(&format!("{USER_SELECT} WHERE id=$1"))
+            .bind(id.as_uuid())
+            .fetch_optional(&self.pool)
+            .await
+            .into_domain()
+            .map(|o| o.map(User::from))
+    }
+
+    async fn find_by_username(&self, username: &Username) -> Result<Option<User>, DomainError> {
+        sqlx::query_as::<_, UserRow>(&format!("{USER_SELECT} WHERE username=$1"))
+            .bind(username.as_str())
+            .fetch_optional(&self.pool)
+            .await
+            .into_domain()
+            .map(|o| o.map(User::from))
+    }
+
+    async fn find_by_email(&self, email: &Email) -> Result<Option<User>, DomainError> {
+        sqlx::query_as::<_, UserRow>(&format!("{USER_SELECT} WHERE email=$1"))
+            .bind(email.as_str())
+            .fetch_optional(&self.pool)
+            .await
+            .into_domain()
+            .map(|o| o.map(User::from))
+    }
+
+    async fn list_with_stats(&self) -> Result<Vec<UserSummary>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            username: String,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            bio: Option<String>,
+            thought_count: i64,
+            follower_count: i64,
+            following_count: i64,
+        }
+        let rows = sqlx::query_as::<_, Row>(
+            "SELECT u.id, u.username, u.display_name, u.avatar_url, u.bio,
+             COUNT(DISTINCT t.id) AS thought_count,
+             COUNT(DISTINCT f1.follower_id) AS follower_count,
+             COUNT(DISTINCT f2.following_id) AS following_count
+             FROM users u
+             LEFT JOIN thoughts t ON t.user_id=u.id AND t.local=true
+             LEFT JOIN follows f1 ON f1.following_id=u.id AND f1.state='accepted'
+             LEFT JOIN follows f2 ON f2.follower_id=u.id AND f2.state='accepted'
+             WHERE u.local=true
+             GROUP BY u.id
+             ORDER BY u.username",
+        )
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(rows
+            .into_iter()
+            .map(|r| UserSummary {
+                id: UserId::from_uuid(r.id),
+                username: r.username,
+                display_name: r.display_name,
+                avatar_url: r.avatar_url,
+                bio: r.bio,
+                thought_count: r.thought_count,
+                follower_count: r.follower_count,
+                following_count: r.following_count,
+            })
+            .collect())
+    }
+
+    async fn count(&self) -> Result<i64, DomainError> {
+        sqlx::query_scalar::<_, i64>("SELECT COUNT(*) FROM users WHERE local = true")
+            .fetch_one(&self.pool)
+            .await
+            .into_domain()
+    }
+
+    async fn list_paginated(&self, page: PageParams) -> Result<Paginated<UserSummary>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            id: uuid::Uuid,
+            username: String,
+            display_name: Option<String>,
+            avatar_url: Option<String>,
+            bio: Option<String>,
+            thought_count: i64,
+            follower_count: i64,
+            following_count: i64,
+            total: i64,
+        }
+        let rows = sqlx::query_as::<_, Row>(
+            "SELECT u.id, u.username, u.display_name, u.avatar_url, u.bio,
+             COUNT(DISTINCT t.id) AS thought_count,
+             COUNT(DISTINCT f1.follower_id) AS follower_count,
+             COUNT(DISTINCT f2.following_id) AS following_count,
+             COUNT(*) OVER() AS total
+             FROM users u
+             LEFT JOIN thoughts t ON t.user_id=u.id AND t.local=true
+             LEFT JOIN follows f1 ON f1.following_id=u.id AND f1.state='accepted'
+             LEFT JOIN follows f2 ON f2.follower_id=u.id AND f2.state='accepted'
+             WHERE u.local=true
+             GROUP BY u.id
+             ORDER BY u.username
+             LIMIT $1 OFFSET $2",
+        )
+        .bind(page.limit())
+        .bind(page.offset())
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        let total = rows.first().map(|r| r.total).unwrap_or(0);
+        let items = rows
+            .into_iter()
+            .map(|r| UserSummary {
+                id: UserId::from_uuid(r.id),
+                username: r.username,
+                display_name: r.display_name,
+                avatar_url: r.avatar_url,
+                bio: r.bio,
+                thought_count: r.thought_count,
+                follower_count: r.follower_count,
+                following_count: r.following_count,
+            })
+            .collect();
+        Ok(Paginated { items, total, page: page.page, per_page: page.per_page })
+    }
+
+    async fn find_by_ids(&self, ids: &[UserId]) -> Result<HashMap<UserId, User>, DomainError> {
+        if ids.is_empty() {
+            return Ok(HashMap::new());
+        }
+        let uuids: Vec<uuid::Uuid> = ids.iter().map(|id| id.as_uuid()).collect();
+        let rows = sqlx::query_as::<_, UserRow>(
+            &format!("{USER_SELECT} WHERE id = ANY($1)")
+        )
+        .bind(&uuids[..])
+        .fetch_all(&self.pool)
+        .await
+        .into_domain()?;
+
+        Ok(rows.into_iter().map(|r| {
+            let user = User::from(r);
+            (user.id.clone(), user)
+        }).collect())
+    }
+}
+
+#[async_trait]
+impl UserWriter for PgUserRepository {
+    async fn save(&self, user: &User) -> Result<(), DomainError> {
+        sqlx::query(
+            "INSERT INTO users (id,username,email,password_hash,display_name,bio,avatar_url,header_url,custom_css,local,created_at,updated_at)
+             VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12)
+             ON CONFLICT(id) DO UPDATE SET
+               username=EXCLUDED.username, email=EXCLUDED.email,
+               password_hash=EXCLUDED.password_hash, display_name=EXCLUDED.display_name,
+               bio=EXCLUDED.bio, avatar_url=EXCLUDED.avatar_url,
+               header_url=EXCLUDED.header_url, custom_css=EXCLUDED.custom_css,
+               local=EXCLUDED.local,
+               updated_at=NOW()"
+        )
+        .bind(user.id.as_uuid())
+        .bind(user.username.as_str())
+        .bind(user.email.as_str())
+        .bind(&user.password_hash.0)
+        .bind(&user.display_name)
+        .bind(&user.bio)
+        .bind(&user.avatar_url)
+        .bind(&user.header_url)
+        .bind(&user.custom_css)
+        .bind(user.local)
+        .bind(user.created_at)
+        .bind(user.updated_at)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| {
+            if let sqlx::Error::Database(ref db) = e {
+                if db.code().as_deref() == Some("23505") {
+                    return match db.constraint().unwrap_or("") {
+                        "users_username_key" => DomainError::UniqueViolation { field: "username" },
+                        "users_email_key"    => DomainError::UniqueViolation { field: "email" },
+                        _                   => DomainError::UniqueViolation { field: "unknown" },
+                    };
+                }
+            }
+            DomainError::Internal(e.to_string())
+        })
+        .map(|_| ())
+    }
+
+    async fn update_profile(
+        &self,
+        user_id: &UserId,
+        display_name: Option<String>,
+        bio: Option<String>,
+        avatar_url: Option<String>,
+        header_url: Option<String>,
+        custom_css: Option<String>,
+    ) -> Result<(), DomainError> {
+        sqlx::query(
+            "UPDATE users SET display_name=$2,bio=$3,avatar_url=$4,header_url=$5,custom_css=$6,updated_at=NOW() WHERE id=$1"
+        )
+        .bind(user_id.as_uuid())
+        .bind(display_name)
+        .bind(bio)
+        .bind(avatar_url)
+        .bind(header_url)
+        .bind(custom_css)
+        .execute(&self.pool)
+        .await
+        .into_domain()
+        .map(|_| ())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{models::user::User, value_objects::*};
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn save_and_find_by_id(pool: sqlx::PgPool) {
+        let repo = PgUserRepository::new(pool);
+        let user = User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("hash".into()),
+        );
+        repo.save(&user).await.unwrap();
+        let found = repo.find_by_id(&user.id).await.unwrap().unwrap();
+        assert_eq!(found.username.as_str(), "alice");
+        assert_eq!(found.email.as_str(), "alice@ex.com");
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn find_by_username_returns_none_when_missing(pool: sqlx::PgPool) {
+        let repo = PgUserRepository::new(pool);
+        let result = repo
+            .find_by_username(&Username::new("ghost").unwrap())
+            .await
+            .unwrap();
+        assert!(result.is_none());
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn find_by_email(pool: sqlx::PgPool) {
+        let repo = PgUserRepository::new(pool);
+        let user = User::new_local(
+            UserId::new(),
+            Username::new("bob").unwrap(),
+            Email::new("bob@ex.com").unwrap(),
+            PasswordHash("hash".into()),
+        );
+        repo.save(&user).await.unwrap();
+        let found = repo
+            .find_by_email(&Email::new("bob@ex.com").unwrap())
+            .await
+            .unwrap();
+        assert!(found.is_some());
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn update_profile_changes_fields(pool: sqlx::PgPool) {
+        let repo = PgUserRepository::new(pool);
+        let user = User::new_local(
+            UserId::new(),
+            Username::new("charlie").unwrap(),
+            Email::new("charlie@ex.com").unwrap(),
+            PasswordHash("hash".into()),
+        );
+        repo.save(&user).await.unwrap();
+        repo.update_profile(
+            &user.id,
+            Some("Charlie".into()),
+            Some("bio".into()),
+            None,
+            None,
+            None,
+        )
+        .await
+        .unwrap();
+        let found = repo.find_by_id(&user.id).await.unwrap().unwrap();
+        assert_eq!(found.display_name.as_deref(), Some("Charlie"));
+        assert_eq!(found.bio.as_deref(), Some("bio"));
+    }
+}

crates/api-types/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "api-types"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+serde  = { workspace = true }
+uuid   = { workspace = true }
+chrono = { workspace = true }
+utoipa = { version = "5.5.0", features = ["uuid", "chrono"] }

crates/api-types/src/lib.rs

@@ -0,0 +1,2 @@
+pub mod requests;
+pub mod responses;

crates/api-types/src/requests.rs

@@ -0,0 +1,92 @@
+use serde::Deserialize;
+use uuid::Uuid;
+
+pub const DEFAULT_PAGE: u64 = 1;
+pub const DEFAULT_PER_PAGE: u64 = 20;
+pub const MAX_PER_PAGE: u64 = 100;
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct RegisterRequest {
+    /// Username (1-32 chars, alphanumeric + underscore)
+    pub username: String,
+    pub email: String,
+    pub password: String,
+}
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct LoginRequest {
+    pub email: String,
+    pub password: String,
+}
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateThoughtRequest {
+    /// Up to 128 characters
+    pub content: String,
+    pub in_reply_to_id: Option<Uuid>,
+    /// One of: "public", "followers", "unlisted", "direct"
+    pub visibility: Option<String>,
+    pub content_warning: Option<String>,
+    pub sensitive: Option<bool>,
+}
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct EditThoughtRequest {
+    pub content: String,
+}
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct UpdateProfileRequest {
+    pub display_name: Option<String>,
+    pub bio: Option<String>,
+    pub avatar_url: Option<String>,
+    pub header_url: Option<String>,
+    pub custom_css: Option<String>,
+}
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct SetTopFriendsRequest {
+    /// Ordered list of user UUIDs, max 8
+    pub friend_ids: Vec<Uuid>,
+}
+
+#[derive(Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateApiKeyRequest {
+    pub name: String,
+}
+
+#[derive(Deserialize, utoipa::IntoParams)]
+pub struct PaginationQuery {
+    pub page: Option<u64>,
+    pub per_page: Option<u64>,
+}
+
+impl PaginationQuery {
+    pub fn page(&self) -> u64 {
+        self.page.unwrap_or(DEFAULT_PAGE).max(DEFAULT_PAGE)
+    }
+
+    pub fn per_page(&self) -> u64 {
+        self.per_page.unwrap_or(DEFAULT_PER_PAGE).min(MAX_PER_PAGE)
+    }
+}
+
+#[derive(Deserialize, utoipa::IntoParams)]
+pub struct SearchQuery {
+    pub q: String,
+    pub page: Option<u64>,
+    pub per_page: Option<u64>,
+}
+
+#[derive(serde::Deserialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct NotificationUpdateRequest {
+    pub read: bool,
+}

crates/api-types/src/responses.rs

@@ -0,0 +1,137 @@
+use chrono::{DateTime, Utc};
+use serde::Serialize;
+use uuid::Uuid;
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct AuthResponse {
+    pub token: String,
+    pub user: UserResponse,
+}
+
+#[derive(Serialize, Clone, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct UserResponse {
+    pub id: Uuid,
+    pub username: String,
+    pub display_name: Option<String>,
+    pub bio: Option<String>,
+    pub avatar_url: Option<String>,
+    pub header_url: Option<String>,
+    pub custom_css: Option<String>,
+    pub local: bool,
+    pub is_followed_by_viewer: bool,
+    #[serde(rename = "joinedAt")]
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Serialize, Clone, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ThoughtResponse {
+    pub id: Uuid,
+    pub content: String,
+    pub author: UserResponse,
+    #[serde(rename = "replyToId")]
+    pub in_reply_to_id: Option<Uuid>,
+    #[serde(rename = "replyToUrl", skip_serializing_if = "Option::is_none")]
+    pub in_reply_to_url: Option<String>,
+    pub visibility: String,
+    pub content_warning: Option<String>,
+    pub sensitive: bool,
+    pub like_count: i64,
+    pub boost_count: i64,
+    pub reply_count: i64,
+    pub liked_by_viewer: bool,
+    pub boosted_by_viewer: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: Option<DateTime<Utc>>,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct PagedResponse<T: Serialize + utoipa::ToSchema> {
+    pub items: Vec<T>,
+    pub total: i64,
+    pub page: u64,
+    pub per_page: u64,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ApiKeyResponse {
+    pub id: Uuid,
+    pub name: String,
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct NotificationResponse {
+    pub id: Uuid,
+    pub notification_type: String,
+    pub from_user: Option<UserResponse>,
+    pub thought_id: Option<Uuid>,
+    pub read: bool,
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct TopFriendsResponse {
+    pub top_friends: Vec<UserResponse>,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ErrorResponse {
+    pub error: String,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreatedApiKeyResponse {
+    pub id: Uuid,
+    pub name: String,
+    /// Raw API key — shown only once at creation
+    pub key: String,
+}
+
+#[derive(Serialize, Clone, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ProfileField {
+    pub name: String,
+    pub value: String,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct RemoteActorResponse {
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+    pub url: String,
+    pub bio: Option<String>,
+    pub banner_url: Option<String>,
+    pub also_known_as: Option<String>,
+    pub outbox_url: Option<String>,
+    pub followers_url: Option<String>,
+    pub following_url: Option<String>,
+    pub attachment: Vec<ProfileField>,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ActorConnectionResponse {
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+    pub url: String,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ActorConnectionPageResponse {
+    pub items: Vec<ActorConnectionResponse>,
+    pub page: u32,
+    pub has_more: bool,
+}

crates/application/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "application"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+domain           = { workspace = true }
+activitypub-base = { workspace = true }
+async-trait      = { workspace = true }
+thiserror   = { workspace = true }
+uuid        = { workspace = true }
+chrono      = { workspace = true }
+sha2        = "0.10"
+hex         = "0.4"
+tracing     = { workspace = true }
+url         = { workspace = true }
+tokio       = { workspace = true }
+
+[dev-dependencies]
+tokio  = { workspace = true, features = ["full"] }
+domain = { workspace = true, features = ["test-helpers"] }

crates/application/src/lib.rs

@@ -0,0 +1,5 @@
+pub mod services;
+pub mod use_cases;
+
+#[cfg(test)]
+pub mod testing;

crates/application/src/services/federation_event.rs

@@ -0,0 +1,787 @@
+use activitypub_base::{ActivityPubRepository, OutboundFederationPort};
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::thought::Visibility,
+    ports::{ThoughtRepository, UserReader},
+    value_objects::ThoughtId,
+};
+use std::sync::Arc;
+
+pub struct FederationEventService {
+    pub thoughts: Arc<dyn ThoughtRepository>,
+    pub users: Arc<dyn UserReader>,
+    pub ap: Arc<dyn OutboundFederationPort>,
+    pub base_url: String,
+    pub ap_repo: Arc<dyn ActivityPubRepository>,
+}
+
+impl FederationEventService {
+    async fn object_ap_id(&self, thought_id: &ThoughtId) -> Result<String, DomainError> {
+        if let Some(ap_id) = self.ap_repo.get_thought_ap_id(thought_id).await? {
+            return Ok(ap_id);
+        }
+        Ok(format!("{}/thoughts/{}", self.base_url, thought_id))
+    }
+
+    pub async fn process(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        match event {
+            DomainEvent::ThoughtCreated {
+                thought_id,
+                user_id,
+                ..
+            } => {
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t)
+                        if t.local
+                            && matches!(
+                                t.visibility,
+                                Visibility::Public | Visibility::Unlisted
+                            ) =>
+                    {
+                        t
+                    }
+                    _ => return Ok(()),
+                };
+                let user = match self.users.find_by_id(user_id).await? {
+                    Some(u) => u,
+                    None => return Ok(()),
+                };
+                // Resolve in_reply_to_url for the parent thought via AP repo.
+                let in_reply_to_url = if let Some(ref reply_id) = thought.in_reply_to_id {
+                    let ap_id = self
+                        .ap_repo
+                        .get_thought_ap_id(reply_id)
+                        .await?
+                        .unwrap_or_else(|| format!("{}/thoughts/{}", self.base_url, reply_id));
+                    Some(ap_id)
+                } else {
+                    None
+                };
+                self.ap
+                    .broadcast_create(
+                        user_id,
+                        &thought,
+                        user.username.as_str(),
+                        in_reply_to_url.as_deref(),
+                    )
+                    .await
+            }
+
+            DomainEvent::ThoughtDeleted {
+                thought_id,
+                user_id,
+            } => {
+                // No DB lookup — thought is already deleted when this event fires.
+                // No locality guard: delete commands only reach local thoughts via the use case.
+                let ap_id = format!("{}/thoughts/{}", self.base_url, thought_id);
+                self.ap.broadcast_delete(user_id, &ap_id).await
+            }
+
+            DomainEvent::ThoughtUpdated {
+                thought_id,
+                user_id,
+            } => {
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t)
+                        if t.local
+                            && matches!(
+                                t.visibility,
+                                Visibility::Public | Visibility::Unlisted
+                            ) =>
+                    {
+                        t
+                    }
+                    _ => return Ok(()),
+                };
+                let user = match self.users.find_by_id(user_id).await? {
+                    Some(u) => u,
+                    None => return Ok(()),
+                };
+                let in_reply_to_url = if let Some(ref reply_id) = thought.in_reply_to_id {
+                    self.ap_repo
+                        .get_thought_ap_id(reply_id)
+                        .await?
+                        .or_else(|| Some(format!("{}/thoughts/{}", self.base_url, reply_id)))
+                } else {
+                    None
+                };
+                self.ap
+                    .broadcast_update(
+                        user_id,
+                        &thought,
+                        user.username.as_str(),
+                        in_reply_to_url.as_deref(),
+                    )
+                    .await
+            }
+
+            DomainEvent::BoostAdded {
+                boost_id: _,
+                user_id,
+                thought_id,
+            } => {
+                // Only fan-out if the booster is a local user. Remote boosts must not be re-broadcast.
+                let booster = match self.users.find_by_id(user_id).await? {
+                    Some(u) if u.local => u,
+                    _ => return Ok(()),
+                };
+                let _ = booster;
+                if self.thoughts.find_by_id(thought_id).await?.is_none() {
+                    return Ok(());
+                }
+                let object_ap_id = self.object_ap_id(thought_id).await?;
+                self.ap.broadcast_announce(user_id, &object_ap_id).await
+            }
+
+            DomainEvent::BoostRemoved {
+                user_id,
+                thought_id,
+            } => {
+                if self.thoughts.find_by_id(thought_id).await?.is_none() {
+                    return Ok(());
+                }
+                let object_ap_id = self.object_ap_id(thought_id).await?;
+                self.ap
+                    .broadcast_undo_announce(user_id, &object_ap_id)
+                    .await
+            }
+
+            DomainEvent::LikeAdded {
+                like_id: _,
+                user_id,
+                thought_id,
+            } => {
+                // Only federate: local liker + remote thought (has ap_id) + author has inbox.
+                let liker = match self.users.find_by_id(user_id).await? {
+                    Some(u) if u.local => u,
+                    _ => return Ok(()),
+                };
+                let _ = liker;
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t) => t,
+                    _ => return Ok(()),
+                };
+                let thought_ap_id = match self.ap_repo.get_thought_ap_id(thought_id).await? {
+                    Some(id) => id,
+                    None => return Ok(()), // local thought — no federation needed
+                };
+                let actor_urls = match self.ap_repo.get_actor_ap_urls(&thought.user_id).await? {
+                    Some(u) => u,
+                    None => return Ok(()),
+                };
+                self.ap
+                    .broadcast_like(user_id, &thought_ap_id, &actor_urls.inbox_url)
+                    .await
+            }
+
+            DomainEvent::LikeRemoved {
+                user_id,
+                thought_id,
+            } => {
+                let liker = match self.users.find_by_id(user_id).await? {
+                    Some(u) if u.local => u,
+                    _ => return Ok(()),
+                };
+                let _ = liker;
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t) => t,
+                    _ => return Ok(()),
+                };
+                let thought_ap_id = match self.ap_repo.get_thought_ap_id(thought_id).await? {
+                    Some(id) => id,
+                    None => return Ok(()),
+                };
+                let actor_urls = match self.ap_repo.get_actor_ap_urls(&thought.user_id).await? {
+                    Some(u) => u,
+                    None => return Ok(()),
+                };
+                self.ap
+                    .broadcast_undo_like(user_id, &thought_ap_id, &actor_urls.inbox_url)
+                    .await
+            }
+
+            DomainEvent::ProfileUpdated { user_id } => {
+                self.ap.broadcast_actor_update(user_id).await
+            }
+
+            _ => Ok(()),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use activitypub_base::{ActorApUrls, OutboundFederationPort};
+    use async_trait::async_trait;
+    use crate::testing::TestApRepo;
+    use domain::{
+        errors::DomainError,
+        events::DomainEvent,
+        models::thought::{Thought, Visibility},
+        models::user::User,
+        testing::TestStore,
+        value_objects::*,
+    };
+    use std::sync::{Arc, Mutex};
+
+    // ── Spy port ─────────────────────────────────────────────────────────────
+
+    #[derive(Default)]
+    struct SpyPort {
+        created: Mutex<Vec<ThoughtId>>,
+        deleted: Mutex<Vec<String>>,
+        updated: Mutex<Vec<ThoughtId>>,
+        announced: Mutex<Vec<String>>,
+        undo_announced: Mutex<Vec<String>>,
+        liked: Mutex<Vec<String>>,
+        undo_liked: Mutex<Vec<String>>,
+        actor_updated: Mutex<Vec<UserId>>,
+    }
+
+    #[async_trait]
+    impl OutboundFederationPort for SpyPort {
+        async fn broadcast_create(
+            &self,
+            _: &UserId,
+            thought: &Thought,
+            _: &str,
+            _in_reply_to_url: Option<&str>,
+        ) -> Result<(), DomainError> {
+            self.created.lock().unwrap().push(thought.id.clone());
+            Ok(())
+        }
+        async fn broadcast_delete(&self, _: &UserId, ap_id: &str) -> Result<(), DomainError> {
+            self.deleted.lock().unwrap().push(ap_id.to_string());
+            Ok(())
+        }
+        async fn broadcast_update(
+            &self,
+            _: &UserId,
+            thought: &Thought,
+            _: &str,
+            _in_reply_to_url: Option<&str>,
+        ) -> Result<(), DomainError> {
+            self.updated.lock().unwrap().push(thought.id.clone());
+            Ok(())
+        }
+        async fn broadcast_announce(&self, _: &UserId, ap_id: &str) -> Result<(), DomainError> {
+            self.announced.lock().unwrap().push(ap_id.to_string());
+            Ok(())
+        }
+        async fn broadcast_undo_announce(
+            &self,
+            _: &UserId,
+            ap_id: &str,
+        ) -> Result<(), DomainError> {
+            self.undo_announced.lock().unwrap().push(ap_id.to_string());
+            Ok(())
+        }
+
+        async fn broadcast_like(
+            &self,
+            _: &UserId,
+            ap_id: &str,
+            _: &str,
+        ) -> Result<(), DomainError> {
+            self.liked.lock().unwrap().push(ap_id.to_string());
+            Ok(())
+        }
+
+        async fn broadcast_undo_like(
+            &self,
+            _: &UserId,
+            ap_id: &str,
+            _: &str,
+        ) -> Result<(), DomainError> {
+            self.undo_liked.lock().unwrap().push(ap_id.to_string());
+            Ok(())
+        }
+
+        async fn broadcast_actor_update(&self, user_id: &UserId) -> Result<(), DomainError> {
+            self.actor_updated.lock().unwrap().push(user_id.clone());
+            Ok(())
+        }
+    }
+
+    fn alice() -> User {
+        User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        )
+    }
+
+    fn local_thought(author_id: UserId) -> Thought {
+        Thought::new_local(
+            ThoughtId::new(),
+            author_id,
+            Content::new_local("hello").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        )
+    }
+
+    fn svc(store: &TestStore, spy: Arc<SpyPort>) -> FederationEventService {
+        let ap_repo = TestApRepo::new(store.clone());
+        FederationEventService {
+            thoughts: Arc::new(store.clone()),
+            users: Arc::new(store.clone()),
+            ap: spy,
+            base_url: "https://example.com".to_string(),
+            ap_repo: Arc::new(ap_repo),
+        }
+    }
+
+    fn svc_with_ap(store: &TestStore, ap_repo: TestApRepo, spy: Arc<SpyPort>) -> FederationEventService {
+        FederationEventService {
+            thoughts: Arc::new(store.clone()),
+            users: Arc::new(store.clone()),
+            ap: spy,
+            base_url: "https://example.com".to_string(),
+            ap_repo: Arc::new(ap_repo),
+        }
+    }
+
+    #[tokio::test]
+    async fn thought_created_broadcasts_create() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone());
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtCreated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+                in_reply_to_id: None,
+            })
+            .await
+            .unwrap();
+
+        assert_eq!(spy.created.lock().unwrap().len(), 1);
+        assert_eq!(spy.created.lock().unwrap()[0], thought.id);
+    }
+
+    #[tokio::test]
+    async fn remote_thought_created_does_not_broadcast() {
+        let store = TestStore::default();
+        let alice = alice();
+        // Remote thought: local = false
+        let mut thought = local_thought(alice.id.clone());
+        thought.local = false;
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtCreated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+                in_reply_to_id: None,
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.created.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn thought_deleted_broadcasts_delete_with_constructed_ap_id() {
+        let store = TestStore::default();
+        let alice = alice();
+        let tid = ThoughtId::new();
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtDeleted {
+                thought_id: tid.clone(),
+                user_id: alice.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let deleted = spy.deleted.lock().unwrap();
+        assert_eq!(deleted.len(), 1);
+        assert_eq!(deleted[0], format!("https://example.com/thoughts/{}", tid));
+    }
+
+    #[tokio::test]
+    async fn thought_updated_broadcasts_update() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone());
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtUpdated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        assert_eq!(spy.updated.lock().unwrap().len(), 1);
+        assert_eq!(spy.updated.lock().unwrap()[0], thought.id);
+    }
+
+    #[tokio::test]
+    async fn boost_of_local_thought_announces_constructed_url() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone()); // ap_id = None
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::BoostAdded {
+                boost_id: BoostId::new(),
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let announced = spy.announced.lock().unwrap();
+        assert_eq!(announced.len(), 1);
+        assert_eq!(
+            announced[0],
+            format!("https://example.com/thoughts/{}", thought.id)
+        );
+    }
+
+    #[tokio::test]
+    async fn boost_of_remote_thought_announces_remote_ap_id() {
+        let store = TestStore::default();
+        let alice = alice();
+        let mut thought = local_thought(alice.id.clone());
+        thought.local = false;
+        let ap_repo = TestApRepo::new(store.clone());
+        ap_repo.inner.thought_ap_ids.lock().unwrap().insert(
+            thought.id.clone(),
+            "https://mastodon.social/users/bob/statuses/123".into(),
+        );
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc_with_ap(&store, ap_repo, spy.clone())
+            .process(&DomainEvent::BoostAdded {
+                boost_id: BoostId::new(),
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let announced = spy.announced.lock().unwrap();
+        assert_eq!(
+            announced[0],
+            "https://mastodon.social/users/bob/statuses/123"
+        );
+    }
+
+    #[tokio::test]
+    async fn direct_thought_created_does_not_broadcast() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("private").unwrap(),
+            None,
+            Visibility::Direct,
+            None,
+            false,
+        );
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtCreated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+                in_reply_to_id: None,
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.created.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn followers_only_thought_does_not_broadcast_publicly() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("for followers").unwrap(),
+            None,
+            Visibility::Followers,
+            None,
+            false,
+        );
+        store.users.lock().unwrap().push(alice.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtCreated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+                in_reply_to_id: None,
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.created.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn unrelated_events_are_noop() {
+        let store = TestStore::default();
+        let spy = Arc::new(SpyPort::default());
+        let svc = svc(&store, spy.clone());
+
+        svc.process(&DomainEvent::UserBlocked {
+            blocker_id: UserId::new(),
+            blocked_id: UserId::new(),
+        })
+        .await
+        .unwrap();
+
+        assert!(spy.created.lock().unwrap().is_empty());
+        assert!(spy.deleted.lock().unwrap().is_empty());
+        assert!(spy.updated.lock().unwrap().is_empty());
+        assert!(spy.announced.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn thought_created_does_not_broadcast_if_user_missing() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone());
+        // Don't push alice into users — simulates user deleted before handler runs
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtCreated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+                in_reply_to_id: None,
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.created.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn boost_removed_sends_undo_announce_for_local_thought() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone()); // ap_id = None → constructed URL
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::BoostRemoved {
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let undo_announced = spy.undo_announced.lock().unwrap();
+        assert_eq!(undo_announced.len(), 1);
+        assert_eq!(
+            undo_announced[0],
+            format!("https://example.com/thoughts/{}", thought.id)
+        );
+    }
+
+    #[tokio::test]
+    async fn boost_removed_sends_undo_announce_for_remote_thought() {
+        let store = TestStore::default();
+        let alice = alice();
+        let mut thought = local_thought(alice.id.clone());
+        thought.local = false;
+        let ap_repo = TestApRepo::new(store.clone());
+        ap_repo.inner.thought_ap_ids.lock().unwrap().insert(
+            thought.id.clone(),
+            "https://mastodon.social/users/bob/statuses/456".into(),
+        );
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc_with_ap(&store, ap_repo, spy.clone())
+            .process(&DomainEvent::BoostRemoved {
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let undo_announced = spy.undo_announced.lock().unwrap();
+        assert_eq!(undo_announced.len(), 1);
+        assert_eq!(
+            undo_announced[0],
+            "https://mastodon.social/users/bob/statuses/456"
+        );
+    }
+
+    #[tokio::test]
+    async fn boost_removed_does_not_broadcast_if_thought_missing() {
+        let store = TestStore::default();
+        let alice = alice();
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::BoostRemoved {
+                user_id: alice.id.clone(),
+                thought_id: ThoughtId::new(), // doesn't exist in store
+            })
+            .await
+            .unwrap();
+        assert!(spy.undo_announced.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn thought_updated_does_not_broadcast_if_user_missing() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone());
+        // Don't push alice into users
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::ThoughtUpdated {
+                thought_id: thought.id.clone(),
+                user_id: alice.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.updated.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn like_added_local_user_remote_thought_broadcasts_like() {
+        let store = TestStore::default();
+
+        let mut author = User::new_local(
+            UserId::new(),
+            Username::new("remote_author").unwrap(),
+            Email::new("r@remote.example").unwrap(),
+            PasswordHash("h".into()),
+        );
+        author.local = false;
+        let thought = local_thought(author.id.clone());
+        let liker = alice();
+
+        store.users.lock().unwrap().push(author.clone());
+        store.users.lock().unwrap().push(liker.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let ap_repo = TestApRepo::new(store.clone());
+        ap_repo.actor_ap_urls.lock().unwrap().insert(
+            author.id.clone(),
+            ActorApUrls {
+                ap_id: "https://mastodon.social/users/author".into(),
+                inbox_url: "https://mastodon.social/users/author/inbox".into(),
+            },
+        );
+        ap_repo.inner.thought_ap_ids.lock().unwrap().insert(
+            thought.id.clone(),
+            "https://mastodon.social/posts/123".into(),
+        );
+
+        let spy = Arc::new(SpyPort::default());
+        svc_with_ap(&store, ap_repo, spy.clone())
+            .process(&DomainEvent::LikeAdded {
+                like_id: LikeId::new(),
+                user_id: liker.id,
+                thought_id: thought.id,
+            })
+            .await
+            .unwrap();
+
+        assert_eq!(spy.liked.lock().unwrap().len(), 1);
+    }
+
+    #[tokio::test]
+    async fn like_added_remote_user_skips_broadcast() {
+        let store = TestStore::default();
+
+        let author = alice();
+        let thought = local_thought(author.id.clone()); // local thought — no ap_id
+
+        let mut remote_liker = User::new_local(
+            UserId::new(),
+            Username::new("bob").unwrap(),
+            Email::new("bob@remote").unwrap(),
+            PasswordHash("h".into()),
+        );
+        remote_liker.local = false;
+
+        store.users.lock().unwrap().push(author);
+        store.users.lock().unwrap().push(remote_liker.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::LikeAdded {
+                like_id: LikeId::new(),
+                user_id: remote_liker.id,
+                thought_id: thought.id,
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.liked.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn boost_added_remote_user_skips_broadcast() {
+        let store = TestStore::default();
+
+        let author = alice();
+        let thought = local_thought(author.id.clone());
+
+        let mut remote_booster = User::new_local(
+            UserId::new(),
+            Username::new("bob").unwrap(),
+            Email::new("bob@remote").unwrap(),
+            PasswordHash("h".into()),
+        );
+        remote_booster.local = false;
+
+        store.users.lock().unwrap().push(author);
+        store.users.lock().unwrap().push(remote_booster.clone());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::BoostAdded {
+                boost_id: BoostId::new(),
+                user_id: remote_booster.id,
+                thought_id: thought.id,
+            })
+            .await
+            .unwrap();
+
+        assert!(spy.announced.lock().unwrap().is_empty());
+    }
+}

crates/application/src/services/mod.rs

@@ -0,0 +1,5 @@
+pub mod federation_event;
+pub mod notification_event;
+
+pub use federation_event::FederationEventService;
+pub use notification_event::NotificationEventService;

crates/application/src/services/notification_event.rs

@@ -0,0 +1,332 @@
+use chrono::Utc;
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::notification::{Notification, NotificationKind},
+    ports::{NotificationRepository, ThoughtRepository},
+    value_objects::NotificationId,
+};
+use std::sync::Arc;
+
+pub struct NotificationEventService {
+    pub thoughts: Arc<dyn ThoughtRepository>,
+    pub notifications: Arc<dyn NotificationRepository>,
+}
+
+fn is_self_action(
+    thought_author: &domain::value_objects::UserId,
+    actor: &domain::value_objects::UserId,
+) -> bool {
+    thought_author == actor
+}
+
+impl NotificationEventService {
+    pub async fn process(&self, event: &DomainEvent) -> Result<(), DomainError> {
+        match event {
+            DomainEvent::LikeAdded {
+                like_id: _,
+                user_id,
+                thought_id,
+            } => {
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t) => t,
+                    None => return Ok(()),
+                };
+                if is_self_action(&thought.user_id, user_id) {
+                    return Ok(());
+                }
+                self.notifications
+                    .save(&Notification {
+                        id: NotificationId::new(),
+                        user_id: thought.user_id,
+                        kind: NotificationKind::Like {
+                            thought_id: thought_id.clone(),
+                            from_user_id: user_id.clone(),
+                        },
+                        read: false,
+                        created_at: Utc::now(),
+                    })
+                    .await
+            }
+            DomainEvent::BoostAdded {
+                boost_id: _,
+                user_id,
+                thought_id,
+            } => {
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t) => t,
+                    None => return Ok(()),
+                };
+                if is_self_action(&thought.user_id, user_id) {
+                    return Ok(());
+                }
+                self.notifications
+                    .save(&Notification {
+                        id: NotificationId::new(),
+                        user_id: thought.user_id,
+                        kind: NotificationKind::Boost {
+                            thought_id: thought_id.clone(),
+                            from_user_id: user_id.clone(),
+                        },
+                        read: false,
+                        created_at: Utc::now(),
+                    })
+                    .await
+            }
+            DomainEvent::FollowAccepted {
+                follower_id,
+                following_id,
+            } => {
+                self.notifications
+                    .save(&Notification {
+                        id: NotificationId::new(),
+                        user_id: following_id.clone(),
+                        kind: NotificationKind::Follow {
+                            from_user_id: follower_id.clone(),
+                        },
+                        read: false,
+                        created_at: Utc::now(),
+                    })
+                    .await
+            }
+            DomainEvent::ThoughtCreated {
+                thought_id,
+                user_id,
+                in_reply_to_id,
+            } => {
+                let reply_to_id = match in_reply_to_id {
+                    Some(id) => id,
+                    None => return Ok(()),
+                };
+                let original = match self.thoughts.find_by_id(reply_to_id).await? {
+                    Some(t) => t,
+                    None => return Ok(()),
+                };
+                if is_self_action(&original.user_id, user_id) {
+                    return Ok(());
+                }
+                self.notifications
+                    .save(&Notification {
+                        id: NotificationId::new(),
+                        user_id: original.user_id,
+                        kind: NotificationKind::Reply {
+                            thought_id: thought_id.clone(),
+                            from_user_id: user_id.clone(),
+                        },
+                        read: false,
+                        created_at: Utc::now(),
+                    })
+                    .await
+            }
+            DomainEvent::MentionReceived {
+                thought_id,
+                mentioned_user_id,
+                author_user_id,
+            } => {
+                self.notifications
+                    .save(&Notification {
+                        id: NotificationId::new(),
+                        user_id: mentioned_user_id.clone(),
+                        kind: NotificationKind::Mention {
+                            thought_id: thought_id.clone(),
+                            from_user_id: author_user_id.clone(),
+                        },
+                        read: false,
+                        created_at: Utc::now(),
+                    })
+                    .await
+            }
+            _ => Ok(()),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{
+        models::{
+            notification::NotificationKind,
+            thought::{Thought, Visibility},
+            user::User,
+        },
+        testing::TestStore,
+        value_objects::*,
+    };
+    use std::sync::Arc;
+
+    fn alice() -> User {
+        User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        )
+    }
+
+    #[tokio::test]
+    async fn like_creates_notification_for_thought_author() {
+        let store = TestStore::default();
+        let alice = alice();
+        let bob_id = UserId::new();
+        let thought = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("hello").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        store.thoughts.lock().unwrap().push(thought.clone());
+        let svc = NotificationEventService {
+            thoughts: Arc::new(store.clone()),
+            notifications: Arc::new(store.clone()),
+        };
+        svc.process(&DomainEvent::LikeAdded {
+            like_id: LikeId::new(),
+            user_id: bob_id,
+            thought_id: thought.id.clone(),
+        })
+        .await
+        .unwrap();
+        let notifs = store.notifications.lock().unwrap();
+        assert_eq!(notifs.len(), 1);
+        assert!(matches!(notifs[0].kind, NotificationKind::Like { .. }));
+    }
+
+    #[tokio::test]
+    async fn self_like_creates_no_notification() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("hello").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        store.thoughts.lock().unwrap().push(thought.clone());
+        let svc = NotificationEventService {
+            thoughts: Arc::new(store.clone()),
+            notifications: Arc::new(store.clone()),
+        };
+        svc.process(&DomainEvent::LikeAdded {
+            like_id: LikeId::new(),
+            user_id: alice.id.clone(),
+            thought_id: thought.id.clone(),
+        })
+        .await
+        .unwrap();
+        assert!(store.notifications.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn follow_accepted_creates_notification() {
+        let store = TestStore::default();
+        let alice = alice();
+        let bob_id = UserId::new();
+        let svc = NotificationEventService {
+            thoughts: Arc::new(store.clone()),
+            notifications: Arc::new(store.clone()),
+        };
+        svc.process(&DomainEvent::FollowAccepted {
+            follower_id: bob_id,
+            following_id: alice.id.clone(),
+        })
+        .await
+        .unwrap();
+        let notifs = store.notifications.lock().unwrap();
+        assert_eq!(notifs.len(), 1);
+        assert!(matches!(notifs[0].kind, NotificationKind::Follow { .. }));
+    }
+
+    #[tokio::test]
+    async fn reply_creates_notification_for_original_author() {
+        let store = TestStore::default();
+        let alice = alice();
+        let bob_id = UserId::new();
+        let original = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("original").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        store.thoughts.lock().unwrap().push(original.clone());
+        let svc = NotificationEventService {
+            thoughts: Arc::new(store.clone()),
+            notifications: Arc::new(store.clone()),
+        };
+        svc.process(&DomainEvent::ThoughtCreated {
+            thought_id: ThoughtId::new(),
+            user_id: bob_id,
+            in_reply_to_id: Some(original.id.clone()),
+        })
+        .await
+        .unwrap();
+        let notifs = store.notifications.lock().unwrap();
+        assert_eq!(notifs.len(), 1);
+        assert!(matches!(notifs[0].kind, NotificationKind::Reply { .. }));
+    }
+
+    #[tokio::test]
+    async fn self_reply_creates_no_notification() {
+        let store = TestStore::default();
+        let alice = alice();
+        let original = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("original").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        store.thoughts.lock().unwrap().push(original.clone());
+        let svc = NotificationEventService {
+            thoughts: Arc::new(store.clone()),
+            notifications: Arc::new(store.clone()),
+        };
+        svc.process(&DomainEvent::ThoughtCreated {
+            thought_id: ThoughtId::new(),
+            user_id: alice.id.clone(),
+            in_reply_to_id: Some(original.id.clone()),
+        })
+        .await
+        .unwrap();
+        assert!(store.notifications.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn self_boost_creates_no_notification() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = Thought::new_local(
+            ThoughtId::new(),
+            alice.id.clone(),
+            Content::new_local("hello").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        );
+        store.thoughts.lock().unwrap().push(thought.clone());
+        let svc = NotificationEventService {
+            thoughts: Arc::new(store.clone()),
+            notifications: Arc::new(store.clone()),
+        };
+        svc.process(&DomainEvent::BoostAdded {
+            boost_id: BoostId::new(),
+            user_id: alice.id.clone(),
+            thought_id: thought.id.clone(),
+        })
+        .await
+        .unwrap();
+        assert!(store.notifications.lock().unwrap().is_empty());
+    }
+}

crates/application/src/testing.rs

@@ -0,0 +1,150 @@
+/// Test helpers for application-layer tests that need activitypub_base traits.
+use activitypub_base::{ActivityPubRepository, ActorApUrls, OutboxEntry};
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    models::user::User,
+    testing::TestStore,
+    value_objects::{Email, PasswordHash, ThoughtId, UserId, Username},
+};
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+
+/// Extends `TestStore` with AP-specific lookup maps.
+#[derive(Default, Clone)]
+pub struct TestApRepo {
+    pub inner: TestStore,
+    /// UserId → ActorApUrls (for get_actor_ap_urls)
+    pub actor_ap_urls: Arc<Mutex<HashMap<UserId, ActorApUrls>>>,
+}
+
+impl TestApRepo {
+    pub fn new(inner: TestStore) -> Self {
+        Self {
+            inner,
+            actor_ap_urls: Default::default(),
+        }
+    }
+}
+
+#[async_trait]
+impl ActivityPubRepository for TestApRepo {
+    async fn outbox_entries_for_actor(
+        &self,
+        _uid: &UserId,
+    ) -> Result<Vec<OutboxEntry>, DomainError> {
+        Ok(vec![])
+    }
+    async fn outbox_page_for_actor(
+        &self,
+        _uid: &UserId,
+        _before: Option<chrono::DateTime<chrono::Utc>>,
+        _limit: usize,
+    ) -> Result<Vec<OutboxEntry>, DomainError> {
+        Ok(vec![])
+    }
+    async fn find_remote_actor_id(
+        &self,
+        actor_ap_url: &str,
+    ) -> Result<Option<UserId>, DomainError> {
+        Ok(self
+            .inner
+            .actor_ap_ids
+            .lock()
+            .unwrap()
+            .get(actor_ap_url)
+            .cloned())
+    }
+    async fn intern_remote_actor(&self, actor_ap_url: &str) -> Result<UserId, DomainError> {
+        if let Some(uid) = self.find_remote_actor_id(actor_ap_url).await? {
+            return Ok(uid);
+        }
+        let uid = UserId::new();
+        let handle = url::Url::parse(actor_ap_url)
+            .map(|u| u.path().trim_start_matches('/').replace('/', "_"))
+            .unwrap_or_else(|_| format!("remote_{}", &uid.to_string()[..8]));
+        let user = User {
+            id: uid.clone(),
+            username: Username::from_trusted(handle),
+            email: Email::from_trusted(format!("{}@remote", uid)),
+            password_hash: PasswordHash("".into()),
+            display_name: None,
+            bio: None,
+            avatar_url: None,
+            header_url: None,
+            custom_css: None,
+            local: false,
+            created_at: chrono::Utc::now(),
+            updated_at: chrono::Utc::now(),
+        };
+        self.inner.users.lock().unwrap().push(user);
+        self.inner
+            .actor_ap_ids
+            .lock()
+            .unwrap()
+            .insert(actor_ap_url.to_string(), uid.clone());
+        Ok(uid)
+    }
+    async fn update_remote_actor_display(
+        &self,
+        _user_id: &UserId,
+        _display_name: Option<&str>,
+        _avatar_url: Option<&str>,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn accept_note(
+        &self,
+        _ap_id: &str,
+        _author_id: &UserId,
+        _content: &str,
+        _published: chrono::DateTime<chrono::Utc>,
+        _sensitive: bool,
+        _content_warning: Option<String>,
+        _visibility: &str,
+        _in_reply_to: Option<&str>,
+    ) -> Result<ThoughtId, DomainError> {
+        Ok(ThoughtId::from_uuid(uuid::Uuid::new_v4()))
+    }
+    async fn apply_note_update(
+        &self,
+        _ap_id: &str,
+        _new_content: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn retract_note(&self, _ap_id: &str) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn retract_actor_notes(&self, _actor_ap_url: &str) -> Result<(), DomainError> {
+        Ok(())
+    }
+    async fn count_local_notes(&self) -> Result<u64, DomainError> {
+        Ok(self
+            .inner
+            .thoughts
+            .lock()
+            .unwrap()
+            .iter()
+            .filter(|t| t.local)
+            .count() as u64)
+    }
+    async fn get_thought_ap_id(
+        &self,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<String>, DomainError> {
+        Ok(self
+            .inner
+            .thought_ap_ids
+            .lock()
+            .unwrap()
+            .get(thought_id)
+            .cloned())
+    }
+    async fn get_actor_ap_urls(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Option<ActorApUrls>, DomainError> {
+        Ok(self.actor_ap_urls.lock().unwrap().get(user_id).cloned())
+    }
+}

crates/application/src/use_cases/api_keys.rs

@@ -0,0 +1,101 @@
+use chrono::Utc;
+use domain::{
+    errors::DomainError,
+    models::api_key::ApiKey,
+    ports::ApiKeyRepository,
+    value_objects::{ApiKeyId, UserId},
+};
+
+pub async fn list_api_keys(
+    keys: &dyn ApiKeyRepository,
+    user_id: &UserId,
+) -> Result<Vec<ApiKey>, DomainError> {
+    keys.list_for_user(user_id).await
+}
+
+pub async fn create_api_key(
+    keys: &dyn ApiKeyRepository,
+    user_id: &UserId,
+    name: String,
+) -> Result<(ApiKey, String), DomainError> {
+    let raw_key = uuid::Uuid::new_v4().to_string().replace('-', "");
+    let key_hash = sha256_hex(&raw_key);
+    let key = ApiKey {
+        id: ApiKeyId::new(),
+        user_id: user_id.clone(),
+        key_hash,
+        name,
+        created_at: Utc::now(),
+    };
+    keys.save(&key).await?;
+    Ok((key, raw_key))
+}
+
+pub async fn delete_api_key(
+    keys: &dyn ApiKeyRepository,
+    user_id: &UserId,
+    key_id: &ApiKeyId,
+) -> Result<(), DomainError> {
+    keys.delete(key_id, user_id).await
+}
+
+fn sha256_hex(s: &str) -> String {
+    use sha2::{Digest, Sha256};
+    let hash = Sha256::digest(s.as_bytes());
+    hex::encode(hash)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{testing::TestStore, value_objects::UserId};
+
+    #[tokio::test]
+    async fn create_key_saves_hashed_not_raw() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let (key, raw) = create_api_key(&store, &uid, "my-key".to_string())
+            .await
+            .unwrap();
+        assert_ne!(key.key_hash, raw, "stored hash must differ from raw key");
+        assert!(!key.key_hash.is_empty());
+        assert_eq!(key.name, "my-key");
+        assert_eq!(key.user_id, uid);
+        assert_eq!(store.api_keys.lock().unwrap().len(), 1);
+    }
+
+    #[tokio::test]
+    async fn raw_key_verifies_against_stored_hash() {
+        use sha2::{Digest, Sha256};
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let (key, raw) = create_api_key(&store, &uid, "test".to_string())
+            .await
+            .unwrap();
+        let expected_hash = hex::encode(Sha256::digest(raw.as_bytes()));
+        assert_eq!(key.key_hash, expected_hash);
+    }
+
+    #[tokio::test]
+    async fn delete_key_removes_it() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let (key, _) = create_api_key(&store, &uid, "k".to_string()).await.unwrap();
+        delete_api_key(&store, &uid, &key.id).await.unwrap();
+        assert!(store.api_keys.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn list_keys_returns_only_own_keys() {
+        let store = TestStore::default();
+        let alice = UserId::new();
+        let bob = UserId::new();
+        create_api_key(&store, &alice, "a".to_string())
+            .await
+            .unwrap();
+        create_api_key(&store, &bob, "b".to_string()).await.unwrap();
+        let alice_keys = list_api_keys(&store, &alice).await.unwrap();
+        assert_eq!(alice_keys.len(), 1);
+        assert_eq!(alice_keys[0].user_id, alice);
+    }
+}

crates/application/src/use_cases/auth.rs

@@ -0,0 +1,388 @@
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::user::User,
+    ports::{AuthService, EventPublisher, PasswordHasher, UserReader, UserRepository},
+    value_objects::{Email, UserId, Username},
+};
+
+pub struct RegisterInput {
+    pub username: String,
+    pub email: String,
+    pub password: String,
+}
+#[derive(Debug)]
+pub struct RegisterOutput {
+    pub user: User,
+    pub token: String,
+}
+
+pub async fn register(
+    users: &dyn UserRepository,
+    hasher: &dyn PasswordHasher,
+    auth: &dyn AuthService,
+    events: &dyn EventPublisher,
+    input: RegisterInput,
+) -> Result<RegisterOutput, DomainError> {
+    let username = Username::new(input.username)?;
+    let email = Email::new(input.email)?;
+    if users.find_by_username(&username).await?.is_some() {
+        return Err(DomainError::Conflict("username taken".into()));
+    }
+    if users.find_by_email(&email).await?.is_some() {
+        return Err(DomainError::Conflict("email taken".into()));
+    }
+    let hash = hasher.hash(&input.password).await?;
+    let user = User::new_local(UserId::new(), username, email, hash);
+    users
+        .save(&user)
+        .await
+        .map_err(|e| match e {
+            DomainError::UniqueViolation { field: "username" } => {
+                DomainError::Conflict("username taken".into())
+            }
+            DomainError::UniqueViolation { field: "email" } => {
+                DomainError::Conflict("email taken".into())
+            }
+            DomainError::UniqueViolation { .. } => {
+                DomainError::Conflict("already exists".into())
+            }
+            other => other,
+        })?;
+    events
+        .publish(&DomainEvent::UserRegistered {
+            user_id: user.id.clone(),
+        })
+        .await?;
+    let token = auth.generate_token(&user.id)?;
+    Ok(RegisterOutput {
+        user,
+        token: token.token,
+    })
+}
+
+pub struct LoginInput {
+    pub email: String,
+    pub password: String,
+}
+#[derive(Debug)]
+pub struct LoginOutput {
+    pub user: User,
+    pub token: String,
+}
+
+pub async fn login(
+    users: &dyn UserReader,
+    hasher: &dyn PasswordHasher,
+    auth: &dyn AuthService,
+    input: LoginInput,
+) -> Result<LoginOutput, DomainError> {
+    let email = Email::new(input.email)?;
+    let user = users.find_by_email(&email).await?;
+    if user.is_none() {
+        // Timing equalization — prevents email enumeration via response-time oracle.
+        // Running the hasher on a miss makes "no such user" take the same time as
+        // "wrong password", so attackers cannot distinguish the two cases.
+        let _ = hasher.hash(&input.password).await;
+        return Err(DomainError::Unauthorized);
+    }
+    let user = user.unwrap();
+    if !hasher.verify(&input.password, &user.password_hash).await? {
+        return Err(DomainError::Unauthorized);
+    }
+    let token = auth.generate_token(&user.id)?;
+    Ok(LoginOutput {
+        user,
+        token: token.token,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use async_trait::async_trait;
+    use domain::{
+        errors::DomainError,
+        events::DomainEvent,
+        models::{feed::{PageParams, Paginated, UserSummary}, user::User},
+        ports::{AuthService, GeneratedToken, PasswordHasher, UserReader, UserWriter},
+        testing::{NoOpEventPublisher, TestStore},
+        value_objects::{Email, PasswordHash, UserId, Username},
+    };
+
+    /// Simulates a concurrent registration that slips past the pre-checks and
+    /// hits the DB unique constraint — exactly what happens in the TOCTOU window.
+    struct ConflictOnSaveStore(TestStore);
+    struct EmailConflictOnSaveStore(TestStore);
+
+    #[async_trait]
+    impl UserReader for ConflictOnSaveStore {
+        async fn find_by_id(&self, id: &UserId) -> Result<Option<User>, DomainError> {
+            self.0.find_by_id(id).await
+        }
+        async fn find_by_username(
+            &self,
+            username: &Username,
+        ) -> Result<Option<User>, DomainError> {
+            self.0.find_by_username(username).await
+        }
+        async fn find_by_email(&self, email: &Email) -> Result<Option<User>, DomainError> {
+            self.0.find_by_email(email).await
+        }
+        async fn list_with_stats(&self) -> Result<Vec<UserSummary>, DomainError> {
+            self.0.list_with_stats().await
+        }
+        async fn count(&self) -> Result<i64, DomainError> {
+            self.0.count().await
+        }
+        async fn list_paginated(&self, page: PageParams) -> Result<Paginated<UserSummary>, DomainError> {
+            self.0.list_paginated(page).await
+        }
+        async fn find_by_ids(&self, ids: &[UserId]) -> Result<std::collections::HashMap<UserId, User>, DomainError> {
+            self.0.find_by_ids(ids).await
+        }
+    }
+
+    #[async_trait]
+    impl UserWriter for ConflictOnSaveStore {
+        async fn save(&self, _user: &User) -> Result<(), DomainError> {
+            Err(DomainError::UniqueViolation { field: "username" })
+        }
+        async fn update_profile(
+            &self,
+            user_id: &UserId,
+            display_name: Option<String>,
+            bio: Option<String>,
+            avatar_url: Option<String>,
+            header_url: Option<String>,
+            custom_css: Option<String>,
+        ) -> Result<(), DomainError> {
+            self.0
+                .update_profile(user_id, display_name, bio, avatar_url, header_url, custom_css)
+                .await
+        }
+    }
+
+    #[async_trait]
+    impl UserReader for EmailConflictOnSaveStore {
+        async fn find_by_id(&self, id: &UserId) -> Result<Option<User>, DomainError> {
+            self.0.find_by_id(id).await
+        }
+        async fn find_by_username(
+            &self,
+            username: &Username,
+        ) -> Result<Option<User>, DomainError> {
+            self.0.find_by_username(username).await
+        }
+        async fn find_by_email(&self, email: &Email) -> Result<Option<User>, DomainError> {
+            self.0.find_by_email(email).await
+        }
+        async fn list_with_stats(&self) -> Result<Vec<UserSummary>, DomainError> {
+            self.0.list_with_stats().await
+        }
+        async fn count(&self) -> Result<i64, DomainError> {
+            self.0.count().await
+        }
+        async fn list_paginated(&self, page: PageParams) -> Result<Paginated<UserSummary>, DomainError> {
+            self.0.list_paginated(page).await
+        }
+        async fn find_by_ids(&self, ids: &[UserId]) -> Result<std::collections::HashMap<UserId, User>, DomainError> {
+            self.0.find_by_ids(ids).await
+        }
+    }
+
+    #[async_trait]
+    impl UserWriter for EmailConflictOnSaveStore {
+        async fn save(&self, _user: &User) -> Result<(), DomainError> {
+            Err(DomainError::UniqueViolation { field: "email" })
+        }
+        async fn update_profile(
+            &self,
+            user_id: &UserId,
+            display_name: Option<String>,
+            bio: Option<String>,
+            avatar_url: Option<String>,
+            header_url: Option<String>,
+            custom_css: Option<String>,
+        ) -> Result<(), DomainError> {
+            self.0
+                .update_profile(user_id, display_name, bio, avatar_url, header_url, custom_css)
+                .await
+        }
+    }
+
+    struct FakeHasher;
+    #[async_trait]
+    impl PasswordHasher for FakeHasher {
+        async fn hash(&self, plain: &str) -> Result<PasswordHash, DomainError> {
+            Ok(PasswordHash(plain.to_string()))
+        }
+        async fn verify(&self, plain: &str, hash: &PasswordHash) -> Result<bool, DomainError> {
+            Ok(plain == hash.0)
+        }
+    }
+
+    struct FakeAuth;
+    impl AuthService for FakeAuth {
+        fn generate_token(&self, uid: &UserId) -> Result<GeneratedToken, DomainError> {
+            Ok(GeneratedToken {
+                token: uid.to_string(),
+                user_id: uid.clone(),
+            })
+        }
+        fn validate_token(&self, token: &str) -> Result<UserId, DomainError> {
+            Ok(UserId::from_uuid(
+                uuid::Uuid::parse_str(token).map_err(|_| DomainError::Unauthorized)?,
+            ))
+        }
+    }
+
+    fn input() -> RegisterInput {
+        RegisterInput {
+            username: "alice".into(),
+            email: "alice@ex.com".into(),
+            password: "pw".into(),
+        }
+    }
+
+    #[tokio::test]
+    async fn register_creates_user() {
+        let store = TestStore::default();
+        let out = register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap();
+        assert_eq!(out.user.username.as_str(), "alice");
+        assert!(!out.token.is_empty());
+    }
+
+    #[tokio::test]
+    async fn register_rejects_duplicate_username() {
+        let store = TestStore::default();
+        register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap();
+        let err = register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap_err();
+        assert!(matches!(err, DomainError::Conflict(_)));
+    }
+
+    #[tokio::test]
+    async fn login_succeeds_with_correct_password() {
+        let store = TestStore::default();
+        register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap();
+        let out = login(
+            &store,
+            &FakeHasher,
+            &FakeAuth,
+            LoginInput {
+                email: "alice@ex.com".into(),
+                password: "pw".into(),
+            },
+        )
+        .await
+        .unwrap();
+        assert!(!out.token.is_empty());
+    }
+
+    #[tokio::test]
+    async fn login_fails_wrong_password() {
+        let store = TestStore::default();
+        register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap();
+        let err = login(
+            &store,
+            &FakeHasher,
+            &FakeAuth,
+            LoginInput {
+                email: "alice@ex.com".into(),
+                password: "wrong".into(),
+            },
+        )
+        .await
+        .unwrap_err();
+        assert!(matches!(err, DomainError::Unauthorized));
+    }
+
+    #[tokio::test]
+    async fn register_publishes_user_registered_event() {
+        let store = TestStore::default();
+        register(&store, &FakeHasher, &FakeAuth, &store, input())
+            .await
+            .unwrap();
+        let events = store.events.lock().unwrap();
+        assert_eq!(events.len(), 1);
+        assert!(matches!(events[0], DomainEvent::UserRegistered { .. }));
+    }
+
+    #[tokio::test]
+    async fn login_fails_for_nonexistent_user() {
+        let store = TestStore::default();
+        let err = login(
+            &store,
+            &FakeHasher,
+            &FakeAuth,
+            LoginInput {
+                email: "ghost@ex.com".into(),
+                password: "pass".into(),
+            },
+        )
+        .await
+        .unwrap_err();
+        assert!(matches!(err, DomainError::Unauthorized));
+    }
+
+    #[tokio::test]
+    async fn register_rejects_duplicate_email() {
+        let store = TestStore::default();
+        register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap();
+        let err = register(
+            &store,
+            &FakeHasher,
+            &FakeAuth,
+            &NoOpEventPublisher,
+            RegisterInput {
+                username: "alice2".into(),
+                email: "alice@ex.com".into(),
+                password: "pass2".into(),
+            },
+        )
+        .await
+        .unwrap_err();
+        assert!(matches!(err, DomainError::Conflict(_)));
+    }
+
+    /// TOCTOU: a concurrent registration slips past the pre-checks and the DB
+    /// unique constraint fires on save. The map_err must convert it to a
+    /// human-readable Conflict, not bubble up a raw constraint name.
+    #[tokio::test]
+    async fn register_maps_db_conflict_on_username_to_conflict() {
+        let store = ConflictOnSaveStore(TestStore::default());
+        let err = register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap_err();
+        assert!(
+            matches!(err, DomainError::Conflict(ref m) if m == "username taken"),
+            "expected 'username taken', got: {:?}",
+            err
+        );
+    }
+
+    #[tokio::test]
+    async fn register_maps_db_conflict_on_email_to_conflict() {
+        let store = EmailConflictOnSaveStore(TestStore::default());
+        let err = register(&store, &FakeHasher, &FakeAuth, &NoOpEventPublisher, input())
+            .await
+            .unwrap_err();
+        assert!(
+            matches!(err, DomainError::Conflict(ref m) if m == "email taken"),
+            "expected 'email taken', got: {:?}",
+            err
+        );
+    }
+}

crates/application/src/use_cases/federation_management.rs

@@ -0,0 +1,191 @@
+use activitypub_base::ActivityPubRepository;
+use domain::{
+    errors::DomainError,
+    models::{
+        actor_connection_summary::ActorConnectionSummary,
+        feed::{FeedEntry, PageParams, Paginated},
+        remote_actor::RemoteActor,
+    },
+    ports::{
+        EventPublisher, FederationActionPort, FederationFollowPort,
+        FederationFollowRequestPort, FederationSchedulerPort, FeedQuery, FeedRepository,
+        FollowRepository, RemoteActorConnectionRepository, UserReader,
+    },
+    value_objects::UserId,
+};
+
+use super::social;
+
+pub async fn list_pending_requests(
+    federation: &dyn FederationFollowRequestPort,
+    user_id: &UserId,
+) -> Result<Vec<RemoteActor>, DomainError> {
+    federation.get_pending_followers(user_id).await
+}
+
+pub async fn accept_follow_request(
+    federation: &dyn FederationFollowRequestPort,
+    user_id: &UserId,
+    actor_url: &str,
+) -> Result<(), DomainError> {
+    federation.accept_follow_request(user_id, actor_url).await
+}
+
+pub async fn reject_follow_request(
+    federation: &dyn FederationFollowRequestPort,
+    user_id: &UserId,
+    actor_url: &str,
+) -> Result<(), DomainError> {
+    federation.reject_follow_request(user_id, actor_url).await
+}
+
+pub async fn list_remote_followers(
+    federation: &dyn FederationFollowRequestPort,
+    user_id: &UserId,
+) -> Result<Vec<RemoteActor>, DomainError> {
+    federation.get_remote_followers(user_id).await
+}
+
+pub async fn remove_remote_follower(
+    federation: &dyn FederationFollowRequestPort,
+    user_id: &UserId,
+    actor_url: &str,
+) -> Result<(), DomainError> {
+    federation.remove_remote_follower(user_id, actor_url).await
+}
+
+pub async fn list_remote_following(
+    federation: &dyn FederationFollowPort,
+    user_id: &UserId,
+) -> Result<Vec<RemoteActor>, DomainError> {
+    federation.get_remote_following(user_id).await
+}
+
+pub async fn remove_remote_following(
+    follows: &dyn FollowRepository,
+    users: &dyn UserReader,
+    federation: &dyn FederationFollowPort,
+    events: &dyn EventPublisher,
+    user_id: &UserId,
+    handle: &str,
+) -> Result<(), DomainError> {
+    social::unfollow_actor(follows, users, federation, events, user_id, handle).await
+}
+
+pub async fn get_remote_actor_posts(
+    federation: &dyn FederationActionPort,
+    ap_repo: &dyn ActivityPubRepository,
+    feed: &dyn FeedRepository,
+    scheduler: &dyn FederationSchedulerPort,
+    handle: &str,
+    page: PageParams,
+    viewer_id: Option<&UserId>,
+) -> Result<Paginated<FeedEntry>, DomainError> {
+    let actor = federation.lookup_actor(handle).await?;
+    let author_id = match ap_repo.find_remote_actor_id(&actor.url).await? {
+        Some(id) => id,
+        None => ap_repo.intern_remote_actor(&actor.url).await?,
+    };
+    let result = feed.query(&FeedQuery::user(author_id, page.clone(), viewer_id.cloned())).await?;
+    if let Some(outbox_url) = actor.outbox_url {
+        let _ = scheduler
+            .schedule_actor_posts_fetch(&actor.url, &outbox_url)
+            .await;
+    }
+    Ok(result)
+}
+
+const ACTOR_CONNECTIONS_CACHE_TTL_SECS: i64 = 3600;
+
+pub async fn get_actor_connections_page(
+    federation: &dyn FederationActionPort,
+    connections: &dyn RemoteActorConnectionRepository,
+    scheduler: &dyn FederationSchedulerPort,
+    handle: &str,
+    connection_type: &str,
+    page: u32,
+) -> Result<(Vec<ActorConnectionSummary>, bool), DomainError> {
+    const PAGE_SIZE: usize = 20;
+    let actor = federation.lookup_actor(handle).await?;
+    let collection_url = match connection_type {
+        "followers" => actor.followers_url.ok_or(DomainError::NotFound)?,
+        _ => actor.following_url.ok_or(DomainError::NotFound)?,
+    };
+    let items = connections
+        .list_connections(&actor.url, connection_type, page)
+        .await?;
+    let stale = match connections
+        .connection_page_age(&actor.url, connection_type, page)
+        .await?
+    {
+        None => true,
+        Some(age) => {
+            chrono::Utc::now().signed_duration_since(age).num_seconds()
+                > ACTOR_CONNECTIONS_CACHE_TTL_SECS
+        }
+    };
+    if stale {
+        let _ = scheduler
+            .schedule_connections_fetch(&actor.url, &collection_url, connection_type, page)
+            .await;
+    }
+    let has_more = items.len() >= PAGE_SIZE;
+    Ok((items, has_more))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::testing::TestStore;
+
+    #[tokio::test]
+    async fn list_pending_returns_empty_by_default() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let result = list_pending_requests(&store, &uid).await.unwrap();
+        assert!(result.is_empty());
+    }
+
+    #[tokio::test]
+    async fn accept_follow_request_returns_ok() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        accept_follow_request(&store, &uid, "https://mastodon.social/users/alice")
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn reject_follow_request_returns_ok() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        reject_follow_request(&store, &uid, "https://mastodon.social/users/alice")
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn list_remote_followers_returns_empty_by_default() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let result = list_remote_followers(&store, &uid).await.unwrap();
+        assert!(result.is_empty());
+    }
+
+    #[tokio::test]
+    async fn remove_remote_follower_returns_ok() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        remove_remote_follower(&store, &uid, "https://mastodon.social/users/alice")
+            .await
+            .unwrap();
+    }
+
+    #[tokio::test]
+    async fn list_remote_following_returns_empty_by_default() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let result = list_remote_following(&store, &uid).await.unwrap();
+        assert!(result.is_empty());
+    }
+}

crates/application/src/use_cases/feed.rs

@@ -0,0 +1,17 @@
+use domain::{
+    errors::DomainError,
+    models::feed::{FeedEntry, PageParams, Paginated},
+    ports::{FeedQuery, FeedRepository, FollowRepository},
+    value_objects::UserId,
+};
+
+pub async fn get_home_feed(
+    feed: &dyn FeedRepository,
+    follows: &dyn FollowRepository,
+    user_id: &UserId,
+    page: PageParams,
+) -> Result<Paginated<FeedEntry>, DomainError> {
+    let mut following_ids = follows.get_accepted_following_ids(user_id).await?;
+    following_ids.push(user_id.clone());
+    feed.query(&FeedQuery::home(user_id.clone(), following_ids, page)).await
+}

crates/application/src/use_cases/mod.rs

@@ -0,0 +1,8 @@
+pub mod api_keys;
+pub mod auth;
+pub mod federation_management;
+pub mod feed;
+pub mod notifications;
+pub mod profile;
+pub mod social;
+pub mod thoughts;

crates/application/src/use_cases/notifications.rs

@@ -0,0 +1,47 @@
+use domain::{
+    errors::DomainError,
+    models::feed::{PageParams, Paginated},
+    models::notification::Notification,
+    ports::NotificationRepository,
+    value_objects::{NotificationId, UserId},
+};
+
+pub async fn list_notifications(
+    repo: &dyn NotificationRepository,
+    user_id: &UserId,
+    page: PageParams,
+) -> Result<Paginated<Notification>, DomainError> {
+    repo.list_for_user(user_id, &page).await
+}
+
+pub async fn count_unread_notifications(
+    repo: &dyn NotificationRepository,
+    user_id: &UserId,
+) -> Result<u64, DomainError> {
+    repo.count_unread(user_id).await
+}
+
+pub async fn mark_notification_read(
+    repo: &dyn NotificationRepository,
+    id: &NotificationId,
+    user_id: &UserId,
+    is_read: bool,
+) -> Result<(), DomainError> {
+    if is_read {
+        repo.mark_read(id, user_id).await
+    } else {
+        Ok(())
+    }
+}
+
+pub async fn mark_all_notifications_read(
+    repo: &dyn NotificationRepository,
+    user_id: &UserId,
+    is_read: bool,
+) -> Result<(), DomainError> {
+    if is_read {
+        repo.mark_all_read(user_id).await
+    } else {
+        Ok(())
+    }
+}

crates/application/src/use_cases/profile.rs

@@ -0,0 +1,163 @@
+const MAX_TOP_FRIENDS: usize = 8;
+
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::{top_friend::TopFriend, user::User},
+    ports::{EventPublisher, TopFriendRepository, UserReader, UserWriter},
+    value_objects::{UserId, Username},
+};
+
+pub async fn get_user(users: &dyn UserReader, user_id: &UserId) -> Result<User, DomainError> {
+    users
+        .find_by_id(user_id)
+        .await?
+        .ok_or(DomainError::NotFound)
+}
+
+pub async fn get_user_by_username(
+    users: &dyn UserReader,
+    username: &str,
+) -> Result<User, DomainError> {
+    let username = Username::new(username).map_err(|_| DomainError::NotFound)?;
+    users
+        .find_by_username(&username)
+        .await?
+        .ok_or(DomainError::NotFound)
+}
+
+/// Resolve a path segment that is either a UUID (AP actor URL) or a username.
+pub async fn get_user_by_id_or_username(
+    users: &dyn UserReader,
+    id_or_username: &str,
+) -> Result<User, DomainError> {
+    if let Ok(uuid) = uuid::Uuid::parse_str(id_or_username) {
+        users
+            .find_by_id(&UserId::from_uuid(uuid))
+            .await?
+            .ok_or(DomainError::NotFound)
+    } else {
+        get_user_by_username(users, id_or_username).await
+    }
+}
+
+#[allow(clippy::too_many_arguments)]
+pub async fn update_profile(
+    users: &dyn UserWriter,
+    events: &dyn EventPublisher,
+    user_id: &UserId,
+    display_name: Option<String>,
+    bio: Option<String>,
+    avatar_url: Option<String>,
+    header_url: Option<String>,
+    custom_css: Option<String>,
+) -> Result<(), DomainError> {
+    users
+        .update_profile(
+            user_id,
+            display_name,
+            bio,
+            avatar_url,
+            header_url,
+            custom_css,
+        )
+        .await?;
+    events
+        .publish(&DomainEvent::ProfileUpdated {
+            user_id: user_id.clone(),
+        })
+        .await
+}
+
+pub async fn get_top_friends(
+    top_friends: &dyn TopFriendRepository,
+    user_id: &UserId,
+) -> Result<Vec<(TopFriend, User)>, DomainError> {
+    top_friends.list_for_user(user_id).await
+}
+
+pub async fn set_top_friends(
+    top_friends: &dyn TopFriendRepository,
+    user_id: &UserId,
+    friend_ids: Vec<UserId>,
+) -> Result<(), DomainError> {
+    if friend_ids.len() > MAX_TOP_FRIENDS {
+        return Err(DomainError::InvalidInput("top friends: max 8".into()));
+    }
+    let friends: Vec<(UserId, i16)> = friend_ids
+        .into_iter()
+        .enumerate()
+        .map(|(i, id)| (id, (i + 1) as i16))
+        .collect();
+    top_friends.set_top_friends(user_id, friends).await
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{
+        errors::DomainError,
+        models::user::User,
+        testing::TestStore,
+        value_objects::{Email, PasswordHash, UserId, Username},
+    };
+
+    fn make_user() -> User {
+        User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        )
+    }
+
+    #[tokio::test]
+    async fn set_top_friends_rejects_more_than_eight() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let friends: Vec<UserId> = (0..9).map(|_| UserId::new()).collect();
+        let err = set_top_friends(&store, &uid, friends).await.unwrap_err();
+        assert!(matches!(err, DomainError::InvalidInput(_)));
+    }
+
+    #[tokio::test]
+    async fn set_top_friends_assigns_sequential_positions() {
+        let store = TestStore::default();
+        let uid = UserId::new();
+        let f1 = UserId::new();
+        let f2 = UserId::new();
+        let f3 = UserId::new();
+        set_top_friends(&store, &uid, vec![f1.clone(), f2.clone(), f3.clone()])
+            .await
+            .unwrap();
+        let tf = store.top_friends.lock().unwrap();
+        assert_eq!(tf.len(), 3);
+        let pos_f1 = tf
+            .iter()
+            .find(|t| t.friend_id == f1)
+            .map(|t| t.position)
+            .unwrap();
+        let pos_f2 = tf
+            .iter()
+            .find(|t| t.friend_id == f2)
+            .map(|t| t.position)
+            .unwrap();
+        assert!(pos_f1 < pos_f2, "f1 should come before f2");
+    }
+
+    #[tokio::test]
+    async fn get_user_by_username_returns_not_found_for_missing_user() {
+        let store = TestStore::default();
+        let err = get_user_by_username(&store, "nobody").await.unwrap_err();
+        assert!(matches!(err, DomainError::NotFound));
+    }
+
+    #[tokio::test]
+    async fn get_user_by_username_returns_correct_user() {
+        let store = TestStore::default();
+        let user = make_user();
+        store.users.lock().unwrap().push(user.clone());
+        let found = get_user_by_username(&store, "alice").await.unwrap();
+        assert_eq!(found.id, user.id);
+    }
+}

crates/application/src/use_cases/social.rs

@@ -0,0 +1,487 @@
+use chrono::Utc;
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::social::{Block, Boost, Follow, FollowState, Like},
+    ports::{
+        BlockRepository, BoostRepository, EventPublisher, FederationFollowPort, FollowRepository,
+        LikeRepository, UserReader,
+    },
+    value_objects::{BoostId, LikeId, ThoughtId, UserId, Username},
+};
+
+pub async fn like_thought(
+    likes: &dyn LikeRepository,
+    events: &dyn EventPublisher,
+    user_id: &UserId,
+    thought_id: &ThoughtId,
+) -> Result<(), DomainError> {
+    let like = Like {
+        id: LikeId::new(),
+        user_id: user_id.clone(),
+        thought_id: thought_id.clone(),
+        ap_id: None,
+        created_at: Utc::now(),
+    };
+    likes.save(&like).await?;
+    events
+        .publish(&DomainEvent::LikeAdded {
+            like_id: like.id,
+            user_id: user_id.clone(),
+            thought_id: thought_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn unlike_thought(
+    likes: &dyn LikeRepository,
+    events: &dyn EventPublisher,
+    user_id: &UserId,
+    thought_id: &ThoughtId,
+) -> Result<(), DomainError> {
+    likes.delete(user_id, thought_id).await?;
+    events
+        .publish(&DomainEvent::LikeRemoved {
+            user_id: user_id.clone(),
+            thought_id: thought_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn boost_thought(
+    boosts: &dyn BoostRepository,
+    events: &dyn EventPublisher,
+    user_id: &UserId,
+    thought_id: &ThoughtId,
+) -> Result<(), DomainError> {
+    let boost = Boost {
+        id: BoostId::new(),
+        user_id: user_id.clone(),
+        thought_id: thought_id.clone(),
+        ap_id: None,
+        created_at: Utc::now(),
+    };
+    boosts.save(&boost).await?;
+    events
+        .publish(&DomainEvent::BoostAdded {
+            boost_id: boost.id,
+            user_id: user_id.clone(),
+            thought_id: thought_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn unboost_thought(
+    boosts: &dyn BoostRepository,
+    events: &dyn EventPublisher,
+    user_id: &UserId,
+    thought_id: &ThoughtId,
+) -> Result<(), DomainError> {
+    boosts.delete(user_id, thought_id).await?;
+    events
+        .publish(&DomainEvent::BoostRemoved {
+            user_id: user_id.clone(),
+            thought_id: thought_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn follow_actor(
+    follows: &dyn FollowRepository,
+    users: &dyn UserReader,
+    federation: &dyn FederationFollowPort,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    username: &str,
+) -> Result<(), DomainError> {
+    if username.contains('@') {
+        federation.follow_remote(follower_id, username).await
+    } else {
+        let uname = Username::new(username)
+            .map_err(|_| DomainError::InvalidInput("invalid username".into()))?;
+        let target = users
+            .find_by_username(&uname)
+            .await?
+            .ok_or(DomainError::NotFound)?;
+        follow_user(follows, events, follower_id, &target.id).await
+    }
+}
+
+pub async fn follow_user(
+    follows: &dyn FollowRepository,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    following_id: &UserId,
+) -> Result<(), DomainError> {
+    if follower_id == following_id {
+        return Err(DomainError::InvalidInput("cannot follow yourself".into()));
+    }
+    let follow = Follow {
+        follower_id: follower_id.clone(),
+        following_id: following_id.clone(),
+        state: FollowState::Accepted,
+        ap_id: None,
+        created_at: Utc::now(),
+    };
+    follows.save(&follow).await?;
+    events
+        .publish(&DomainEvent::FollowAccepted {
+            follower_id: follower_id.clone(),
+            following_id: following_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn unfollow_actor(
+    follows: &dyn FollowRepository,
+    users: &dyn UserReader,
+    federation: &dyn FederationFollowPort,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    username: &str,
+) -> Result<(), DomainError> {
+    if username.contains('@') {
+        federation.unfollow_remote(follower_id, username).await
+    } else {
+        let uname = Username::new(username)
+            .map_err(|_| DomainError::InvalidInput("invalid username".into()))?;
+        let target = users
+            .find_by_username(&uname)
+            .await?
+            .ok_or(DomainError::NotFound)?;
+        unfollow_user(follows, events, follower_id, &target.id).await
+    }
+}
+
+pub async fn unfollow_user(
+    follows: &dyn FollowRepository,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    following_id: &UserId,
+) -> Result<(), DomainError> {
+    follows.delete(follower_id, following_id).await?;
+    events
+        .publish(&DomainEvent::Unfollowed {
+            follower_id: follower_id.clone(),
+            following_id: following_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn accept_follow(
+    follows: &dyn FollowRepository,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    following_id: &UserId,
+) -> Result<(), DomainError> {
+    follows
+        .update_state(follower_id, following_id, &FollowState::Accepted)
+        .await?;
+    events
+        .publish(&DomainEvent::FollowAccepted {
+            follower_id: follower_id.clone(),
+            following_id: following_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn reject_follow(
+    follows: &dyn FollowRepository,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    following_id: &UserId,
+) -> Result<(), DomainError> {
+    follows
+        .update_state(follower_id, following_id, &FollowState::Rejected)
+        .await?;
+    events
+        .publish(&DomainEvent::FollowRejected {
+            follower_id: follower_id.clone(),
+            following_id: following_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn block_by_username(
+    blocks: &dyn BlockRepository,
+    users: &dyn UserReader,
+    events: &dyn EventPublisher,
+    blocker_id: &UserId,
+    username: &str,
+) -> Result<(), DomainError> {
+    let uname = Username::new(username).map_err(|_| DomainError::NotFound)?;
+    let target = users
+        .find_by_username(&uname)
+        .await?
+        .ok_or(DomainError::NotFound)?;
+    block_user(blocks, events, blocker_id, &target.id).await
+}
+
+pub async fn unblock_by_username(
+    blocks: &dyn BlockRepository,
+    users: &dyn UserReader,
+    events: &dyn EventPublisher,
+    blocker_id: &UserId,
+    username: &str,
+) -> Result<(), DomainError> {
+    let uname = Username::new(username).map_err(|_| DomainError::NotFound)?;
+    let target = users
+        .find_by_username(&uname)
+        .await?
+        .ok_or(DomainError::NotFound)?;
+    unblock_user(blocks, events, blocker_id, &target.id).await
+}
+
+pub async fn block_user(
+    blocks: &dyn BlockRepository,
+    events: &dyn EventPublisher,
+    blocker_id: &UserId,
+    blocked_id: &UserId,
+) -> Result<(), DomainError> {
+    if blocker_id == blocked_id {
+        return Err(DomainError::InvalidInput("cannot block yourself".into()));
+    }
+    let block = Block {
+        blocker_id: blocker_id.clone(),
+        blocked_id: blocked_id.clone(),
+        created_at: Utc::now(),
+    };
+    blocks.save(&block).await?;
+    events
+        .publish(&DomainEvent::UserBlocked {
+            blocker_id: blocker_id.clone(),
+            blocked_id: blocked_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn unblock_user(
+    blocks: &dyn BlockRepository,
+    events: &dyn EventPublisher,
+    blocker_id: &UserId,
+    blocked_id: &UserId,
+) -> Result<(), DomainError> {
+    blocks.delete(blocker_id, blocked_id).await?;
+    events
+        .publish(&DomainEvent::UserUnblocked {
+            blocker_id: blocker_id.clone(),
+            blocked_id: blocked_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{
+        models::{
+            thought::{Thought, Visibility},
+            user::User,
+        },
+        testing::TestStore,
+        value_objects::*,
+    };
+
+    fn user(name: &str) -> User {
+        User::new_local(
+            UserId::new(),
+            Username::new(name).unwrap(),
+            Email::new(format!("{name}@ex.com")).unwrap(),
+            PasswordHash("h".into()),
+        )
+    }
+
+    #[tokio::test]
+    async fn like_and_unlike() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let tid = ThoughtId::new();
+        store.thoughts.lock().unwrap().push(Thought::new_local(
+            tid.clone(),
+            alice.id.clone(),
+            Content::new_local("hi").unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        ));
+        like_thought(&store, &store, &alice.id, &tid).await.unwrap();
+        assert_eq!(store.likes.lock().unwrap().len(), 1);
+        unlike_thought(&store, &store, &alice.id, &tid)
+            .await
+            .unwrap();
+        assert!(store.likes.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn follow_and_unfollow() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let bob = user("bob");
+        follow_user(&store, &store, &alice.id, &bob.id)
+            .await
+            .unwrap();
+        assert_eq!(store.follows.lock().unwrap().len(), 1);
+        unfollow_user(&store, &store, &alice.id, &bob.id)
+            .await
+            .unwrap();
+        assert!(store.follows.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn cannot_follow_self() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let err = follow_user(&store, &store, &alice.id, &alice.id)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, DomainError::InvalidInput(_)));
+    }
+
+    #[tokio::test]
+    async fn unblock_user_publishes_event() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let bob = user("bob");
+        block_user(&store, &store, &alice.id, &bob.id)
+            .await
+            .unwrap();
+        store.events.lock().unwrap().clear();
+        unblock_user(&store, &store, &alice.id, &bob.id)
+            .await
+            .unwrap();
+        let events = store.events.lock().unwrap();
+        assert_eq!(events.len(), 1);
+        assert!(matches!(events[0], DomainEvent::UserUnblocked { .. }));
+    }
+
+    #[tokio::test]
+    async fn block_user_saves_block_and_publishes_event() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let bob = user("bob");
+        block_user(&store, &store, &alice.id, &bob.id)
+            .await
+            .unwrap();
+        assert_eq!(store.blocks.lock().unwrap().len(), 1);
+        let events = store.events.lock().unwrap();
+        assert!(events.iter().any(
+            |e| matches!(e, DomainEvent::UserBlocked { blocker_id, .. } if blocker_id == &alice.id)
+        ));
+    }
+
+    #[tokio::test]
+    async fn cannot_block_self() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let err = block_user(&store, &store, &alice.id, &alice.id)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, DomainError::InvalidInput(_)));
+    }
+
+    #[tokio::test]
+    async fn follow_actor_local_routes_to_follow_user() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let bob = user("bob");
+        store.users.lock().unwrap().push(bob.clone());
+        follow_actor(&store, &store, &store, &store, &alice.id, "bob")
+            .await
+            .unwrap();
+        assert_eq!(store.follows.lock().unwrap().len(), 1);
+    }
+
+    #[tokio::test]
+    async fn follow_actor_remote_routes_to_federation() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        follow_actor(
+            &store,
+            &store,
+            &store,
+            &store,
+            &alice.id,
+            "@bob@example.com",
+        )
+        .await
+        .unwrap();
+        // TestStore.follow_remote is a no-op that returns Ok(())
+        // no local follow should be recorded
+        assert!(store.follows.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn unfollow_actor_local_routes_to_unfollow_user() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let bob = user("bob");
+        store.users.lock().unwrap().push(bob.clone());
+        // Create an existing follow first
+        store
+            .follows
+            .lock()
+            .unwrap()
+            .push(domain::models::social::Follow {
+                follower_id: alice.id.clone(),
+                following_id: bob.id.clone(),
+                state: domain::models::social::FollowState::Accepted,
+                ap_id: None,
+                created_at: chrono::Utc::now(),
+            });
+        unfollow_actor(&store, &store, &store, &store, &alice.id, "bob")
+            .await
+            .unwrap();
+        assert!(store.follows.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn unfollow_actor_remote_routes_to_federation() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        unfollow_actor(
+            &store,
+            &store,
+            &store,
+            &store,
+            &alice.id,
+            "@bob@example.com",
+        )
+        .await
+        .unwrap();
+        // TestStore.unfollow_remote is a no-op — just verify it doesn't error
+        assert!(store.follows.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn boost_and_unboost() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let tid = ThoughtId::new();
+        boost_thought(&store, &store, &alice.id, &tid)
+            .await
+            .unwrap();
+        assert_eq!(store.boosts.lock().unwrap().len(), 1);
+        unboost_thought(&store, &store, &alice.id, &tid)
+            .await
+            .unwrap();
+        assert!(store.boosts.lock().unwrap().is_empty());
+        let events = store.events.lock().unwrap();
+        assert!(events
+            .iter()
+            .any(|e| matches!(e, DomainEvent::BoostAdded { .. })));
+        assert!(events
+            .iter()
+            .any(|e| matches!(e, DomainEvent::BoostRemoved { .. })));
+    }
+}

crates/application/src/use_cases/thoughts.rs

@@ -0,0 +1,456 @@
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::{
+        feed::{EngagementStats, FeedEntry},
+        thought::{Thought, Visibility},
+    },
+    ports::{EngagementRepository, EventPublisher, OutboxWriter, TagRepository, ThoughtRepository, UserReader},
+    value_objects::{Content, ThoughtId, UserId},
+};
+
+fn require_owner(thought: &Thought, user_id: &UserId) -> Result<(), DomainError> {
+    if thought.user_id != *user_id {
+        return Err(DomainError::NotFound);
+    }
+    Ok(())
+}
+
+pub struct CreateThoughtInput {
+    pub user_id: UserId,
+    pub content: String,
+    pub in_reply_to_id: Option<ThoughtId>,
+    pub visibility: Option<String>,
+    pub content_warning: Option<String>,
+    pub sensitive: bool,
+}
+pub struct CreateThoughtOutput {
+    pub thought: Thought,
+}
+
+pub async fn create_thought(
+    thoughts: &dyn ThoughtRepository,
+    _users: &dyn UserReader,
+    tags: &dyn TagRepository,
+    _events: &dyn EventPublisher,
+    outbox: &dyn OutboxWriter,
+    input: CreateThoughtInput,
+) -> Result<CreateThoughtOutput, DomainError> {
+    let content = Content::new_local(input.content)?;
+    let visibility = match input.visibility.as_deref() {
+        Some("followers") => Visibility::Followers,
+        Some("unlisted") => Visibility::Unlisted,
+        Some("direct") => Visibility::Direct,
+        _ => Visibility::Public,
+    };
+    let thought = Thought::new_local(
+        ThoughtId::new(),
+        input.user_id,
+        content.clone(),
+        input.in_reply_to_id.clone(),
+        visibility,
+        input.content_warning,
+        input.sensitive,
+    );
+    thoughts.save(&thought).await?;
+
+    // Extract and attach hashtags from content.
+    for h in domain::hashtag::extract(content.as_str()) {
+        if let Ok(tag) = tags.find_or_create(&h.normalized).await {
+            let _ = tags.attach_to_thought(&thought.id, tag.id).await;
+        }
+    }
+
+    outbox
+        .append(&DomainEvent::ThoughtCreated {
+            thought_id: thought.id.clone(),
+            user_id: thought.user_id.clone(),
+            in_reply_to_id: input.in_reply_to_id,
+        })
+        .await?;
+    Ok(CreateThoughtOutput { thought })
+}
+
+pub async fn delete_thought(
+    thoughts: &dyn ThoughtRepository,
+    _events: &dyn EventPublisher,
+    outbox: &dyn OutboxWriter,
+    id: &ThoughtId,
+    user_id: &UserId,
+) -> Result<(), DomainError> {
+    let thought = thoughts
+        .find_by_id(id)
+        .await?
+        .ok_or(DomainError::NotFound)?;
+    require_owner(&thought, user_id)?;
+    thoughts.delete(id, user_id).await?;
+    outbox
+        .append(&DomainEvent::ThoughtDeleted {
+            thought_id: id.clone(),
+            user_id: user_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+pub async fn edit_thought(
+    thoughts: &dyn ThoughtRepository,
+    events: &dyn EventPublisher,
+    id: &ThoughtId,
+    user_id: &UserId,
+    new_content: String,
+) -> Result<(), DomainError> {
+    let thought = thoughts
+        .find_by_id(id)
+        .await?
+        .ok_or(DomainError::NotFound)?;
+    require_owner(&thought, user_id)?;
+    let content = Content::new_local(new_content)?;
+    thoughts.update_content(id, &content).await?;
+    events
+        .publish(&DomainEvent::ThoughtUpdated {
+            thought_id: id.clone(),
+            user_id: user_id.clone(),
+        })
+        .await?;
+    Ok(())
+}
+
+/// Fetches a single thought enriched with author + real engagement stats.
+pub async fn get_thought_view(
+    thoughts: &dyn ThoughtRepository,
+    users: &dyn UserReader,
+    engagement: &dyn EngagementRepository,
+    id: &ThoughtId,
+    viewer: Option<&UserId>,
+) -> Result<FeedEntry, DomainError> {
+    let thought = thoughts
+        .find_by_id(id)
+        .await?
+        .ok_or(DomainError::NotFound)?;
+    let author = users
+        .find_by_id(&thought.user_id)
+        .await?
+        .ok_or(DomainError::NotFound)?;
+    let mut map = engagement.get_for_thoughts(&[id.clone()], viewer).await?;
+    let (stats, viewer_ctx) = map.remove(id).unwrap_or(
+        (EngagementStats { like_count: 0, boost_count: 0, reply_count: 0 }, None)
+    );
+    Ok(FeedEntry { thought, author, stats, viewer: viewer_ctx })
+}
+
+/// Fetches a thread (root + replies) enriched with authors + real engagement stats.
+/// Batches all DB lookups — one query per resource type regardless of thread length.
+pub async fn get_thread_views(
+    thoughts: &dyn ThoughtRepository,
+    users: &dyn UserReader,
+    engagement: &dyn EngagementRepository,
+    root_id: &ThoughtId,
+    viewer: Option<&UserId>,
+) -> Result<Vec<FeedEntry>, DomainError> {
+    let thread = thoughts.get_thread(root_id).await?;
+    if thread.is_empty() {
+        return Ok(vec![]);
+    }
+
+    let thought_ids: Vec<ThoughtId> = thread.iter().map(|t| t.id.clone()).collect();
+    let user_ids: Vec<UserId> = thread.iter().map(|t| t.user_id.clone()).collect();
+
+    let (authors_map, engagement_map) = tokio::join!(
+        users.find_by_ids(&user_ids),
+        engagement.get_for_thoughts(&thought_ids, viewer),
+    );
+    let authors_map = authors_map?;
+    let mut engagement_map = engagement_map?;
+
+    let mut entries = Vec::with_capacity(thread.len());
+    for thought in thread {
+        let author = authors_map
+            .get(&thought.user_id)
+            .cloned()
+            .ok_or(DomainError::NotFound)?;
+        let (stats, viewer_ctx) = engagement_map.remove(&thought.id).unwrap_or(
+            (EngagementStats { like_count: 0, boost_count: 0, reply_count: 0 }, None)
+        );
+        entries.push(FeedEntry { thought, author, stats, viewer: viewer_ctx });
+    }
+    Ok(entries)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use domain::{
+        models::user::User,
+        testing::{NoOpEventPublisher, NoOpOutboxWriter, TestOutbox, TestStore},
+        value_objects::*,
+    };
+
+    fn user() -> User {
+        User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("alice@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        )
+    }
+
+    fn input(uid: UserId) -> CreateThoughtInput {
+        CreateThoughtInput {
+            user_id: uid,
+            content: "hello".into(),
+            in_reply_to_id: None,
+            visibility: None,
+            content_warning: None,
+            sensitive: false,
+        }
+    }
+
+    #[tokio::test]
+    async fn create_thought_saves_and_stages_outbox_event() {
+        let store = TestStore::default();
+        let outbox = TestOutbox::default();
+        let u = user();
+        store.users.lock().unwrap().push(u.clone());
+        let out = create_thought(&store, &store, &store, &NoOpEventPublisher, &outbox, input(u.id.clone()))
+            .await
+            .unwrap();
+        assert_eq!(out.thought.content.as_str(), "hello");
+        let staged = outbox.staged();
+        assert_eq!(staged.len(), 1);
+        assert!(matches!(staged[0], DomainEvent::ThoughtCreated { .. }));
+    }
+
+    #[tokio::test]
+    async fn delete_thought_stages_outbox_event() {
+        let store = TestStore::default();
+        let outbox = TestOutbox::default();
+        let u = user();
+        store.users.lock().unwrap().push(u.clone());
+        let out = create_thought(
+            &store,
+            &store,
+            &store,
+            &NoOpEventPublisher,
+            &NoOpOutboxWriter,
+            input(u.id.clone()),
+        )
+        .await
+        .unwrap();
+        let tid = out.thought.id.clone();
+
+        delete_thought(&store, &NoOpEventPublisher, &outbox, &tid, &u.id)
+            .await
+            .unwrap();
+
+        let staged = outbox.staged();
+        assert_eq!(staged.len(), 1);
+        assert!(matches!(&staged[0], DomainEvent::ThoughtDeleted { thought_id, .. } if *thought_id == tid));
+    }
+
+    #[tokio::test]
+    async fn delete_own_thought_succeeds() {
+        let store = TestStore::default();
+        let u = user();
+        store.users.lock().unwrap().push(u.clone());
+        let out = create_thought(
+            &store,
+            &store,
+            &store,
+            &NoOpEventPublisher,
+            &NoOpOutboxWriter,
+            input(u.id.clone()),
+        )
+        .await
+        .unwrap();
+        delete_thought(&store, &NoOpEventPublisher, &NoOpOutboxWriter, &out.thought.id, &u.id)
+            .await
+            .unwrap();
+        assert!(store.thoughts.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn delete_other_thought_returns_not_found() {
+        let store = TestStore::default();
+        let alice = user();
+        let bob = User::new_local(
+            UserId::new(),
+            Username::new("bob").unwrap(),
+            Email::new("bob@ex.com").unwrap(),
+            PasswordHash("h".into()),
+        );
+        store
+            .users
+            .lock()
+            .unwrap()
+            .extend([alice.clone(), bob.clone()]);
+        let out = create_thought(
+            &store,
+            &store,
+            &store,
+            &NoOpEventPublisher,
+            &NoOpOutboxWriter,
+            input(alice.id.clone()),
+        )
+        .await
+        .unwrap();
+        let err = delete_thought(&store, &NoOpEventPublisher, &NoOpOutboxWriter, &out.thought.id, &bob.id)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, DomainError::NotFound));
+    }
+
+    #[tokio::test]
+    async fn edit_thought_changes_content_and_emits_event() {
+        let store = TestStore::default();
+        let alice = user();
+        store.users.lock().unwrap().push(alice.clone());
+        let out = create_thought(&store, &store, &store, &NoOpEventPublisher, &NoOpOutboxWriter, input(alice.id.clone()))
+            .await
+            .unwrap();
+        let tid = out.thought.id.clone();
+
+        edit_thought(&store, &store, &tid, &alice.id, "updated".to_string())
+            .await
+            .unwrap();
+
+        let saved = store
+            .thoughts
+            .lock()
+            .unwrap()
+            .iter()
+            .find(|t| t.id == tid)
+            .unwrap()
+            .clone();
+        assert_eq!(saved.content.as_str(), "updated");
+
+        let events = store.events.lock().unwrap();
+        assert!(events.iter().any(
+            |e| matches!(e, DomainEvent::ThoughtUpdated { thought_id, .. } if thought_id == &tid)
+        ));
+    }
+
+    #[tokio::test]
+    async fn create_reply_sets_in_reply_to_id() {
+        let store = TestStore::default();
+        let alice = user();
+        store.users.lock().unwrap().push(alice.clone());
+        let original = create_thought(
+            &store,
+            &store,
+            &store,
+            &NoOpEventPublisher,
+            &NoOpOutboxWriter,
+            input(alice.id.clone()),
+        )
+        .await
+        .unwrap()
+        .thought;
+
+        create_thought(
+            &store,
+            &store,
+            &store,
+            &NoOpEventPublisher,
+            &NoOpOutboxWriter,
+            CreateThoughtInput {
+                user_id: alice.id.clone(),
+                content: "reply".into(),
+                in_reply_to_id: Some(original.id.clone()),
+                visibility: None,
+                content_warning: None,
+                sensitive: false,
+            },
+        )
+        .await
+        .unwrap();
+
+        let thoughts = store.thoughts.lock().unwrap();
+        let reply = thoughts
+            .iter()
+            .find(|t| t.content.as_str() == "reply")
+            .unwrap();
+        assert_eq!(reply.in_reply_to_id, Some(original.id.clone()));
+    }
+}
+
+#[cfg(test)]
+mod enrichment_tests {
+    use super::*;
+    use domain::testing::TestStore;
+    use domain::models::user::User;
+    use domain::models::thought::{Thought, Visibility};
+    use domain::value_objects::*;
+    use domain::ports::{ThoughtRepository, UserWriter};
+
+    fn make_user() -> User {
+        User::new_local(
+            UserId::new(),
+            Username::new("alice").unwrap(),
+            Email::new("a@a.com").unwrap(),
+            PasswordHash("h".into()),
+        )
+    }
+
+    fn make_thought(user_id: UserId) -> Thought {
+        Thought::new_local(
+            ThoughtId::new(),
+            user_id,
+            Content::new_local(String::from("hello")).unwrap(),
+            None,
+            Visibility::Public,
+            None,
+            false,
+        )
+    }
+
+    #[tokio::test]
+    async fn get_thought_view_returns_feed_entry() {
+        let store = TestStore::default();
+        let user = make_user();
+        <TestStore as UserWriter>::save(&store, &user).await.unwrap();
+        let thought = make_thought(user.id.clone());
+        <TestStore as ThoughtRepository>::save(&store, &thought).await.unwrap();
+
+        let entry = get_thought_view(&store, &store, &store, &thought.id, None)
+            .await
+            .unwrap();
+        assert_eq!(entry.thought.id, thought.id);
+        assert_eq!(entry.author.id, user.id);
+        assert_eq!(entry.stats.like_count, 0);
+        assert!(entry.viewer.is_none());
+    }
+
+    #[tokio::test]
+    async fn get_thought_view_returns_not_found_for_missing_thought() {
+        let store = TestStore::default();
+        let err = get_thought_view(&store, &store, &store, &ThoughtId::new(), None)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, DomainError::NotFound));
+    }
+
+    #[tokio::test]
+    async fn get_thread_views_batches_correctly() {
+        let store = TestStore::default();
+        let user = make_user();
+        <TestStore as UserWriter>::save(&store, &user).await.unwrap();
+        let root = make_thought(user.id.clone());
+        <TestStore as ThoughtRepository>::save(&store, &root).await.unwrap();
+        let reply = Thought::new_local(
+            ThoughtId::new(),
+            user.id.clone(),
+            Content::new_local(String::from("reply")).unwrap(),
+            Some(root.id.clone()),
+            Visibility::Public,
+            None,
+            false,
+        );
+        <TestStore as ThoughtRepository>::save(&store, &reply).await.unwrap();
+
+        let entries = get_thread_views(&store, &store, &store, &root.id, None)
+            .await
+            .unwrap();
+        assert_eq!(entries.len(), 2);
+    }
+}

crates/bootstrap/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+name = "bootstrap"
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "thoughts"
+path = "src/main.rs"
+
+[dependencies]
+presentation        = { workspace = true }
+domain              = { workspace = true }
+postgres            = { workspace = true }
+postgres-search     = { workspace = true }
+postgres-federation = { workspace = true }
+activitypub         = { workspace = true }
+activitypub-base    = { workspace = true }
+nats                = { workspace = true }
+event-transport     = { workspace = true }
+auth                = { workspace = true }
+sqlx                = { workspace = true }
+async-nats          = { workspace = true }
+async-trait         = { workspace = true }
+tokio               = { workspace = true, features = ["full"] }
+axum                = { workspace = true }
+tower-http          = { workspace = true }
+tracing             = { workspace = true }
+tracing-subscriber  = { workspace = true }
+dotenvy             = { workspace = true }
+tower_governor      = "0.8"
+http                = "1"

crates/bootstrap/src/config.rs

@@ -0,0 +1,41 @@
+/// All configuration read from environment variables at startup.
+pub struct Config {
+    pub database_url: String,
+    pub jwt_secret: String,
+    pub base_url: String,
+    pub nats_url: Option<String>,
+    pub port: u16,
+    pub allow_registration: bool,
+    /// true when RUST_ENV != "production" — enables AP debug mode
+    pub debug: bool,
+    pub host: String,
+    pub cors_origins: String,
+    pub rate_limit: Option<u32>,
+}
+
+impl Config {
+    pub fn from_env() -> Self {
+        dotenvy::dotenv().ok();
+        Self {
+            database_url: std::env::var("DATABASE_URL").expect("DATABASE_URL is required"),
+            jwt_secret: std::env::var("JWT_SECRET").expect("JWT_SECRET is required"),
+            base_url: std::env::var("BASE_URL").unwrap_or_else(|_| "http://localhost:3000".into()),
+            nats_url: std::env::var("NATS_URL").ok(),
+            port: std::env::var("PORT")
+                .ok()
+                .and_then(|p| p.parse().ok())
+                .unwrap_or(3000),
+            allow_registration: std::env::var("ALLOW_REGISTRATION")
+                .map(|v| v == "true")
+                .unwrap_or(true),
+            debug: std::env::var("RUST_ENV")
+                .map(|v| v != "production")
+                .unwrap_or(true),
+            host: std::env::var("HOST").unwrap_or_else(|_| "0.0.0.0".into()),
+            cors_origins: std::env::var("CORS_ORIGINS").unwrap_or_else(|_| "*".into()),
+            rate_limit: std::env::var("RATE_LIMIT")
+                .ok()
+                .and_then(|v| v.parse().ok()),
+        }
+    }
+}

crates/bootstrap/src/factory.rs

@@ -0,0 +1,139 @@
+const JWT_TTL_SECS: i64 = 86_400; // 24 hours (was 30 days)
+const JWT_SECRET_MIN_BYTES: usize = 32; // 256 bits minimum for HS256
+
+use async_trait::async_trait;
+use sqlx::PgPool;
+use std::sync::Arc;
+
+use activitypub::ThoughtsObjectHandler;
+use activitypub_base::service::ActivityPubService;
+use auth::ApiKeyServiceImpl;
+use domain::{errors::DomainError, events::DomainEvent, ports::{EventPublisher, OutboxWriter}};
+use event_transport::EventPublisherAdapter;
+use nats::NatsTransport;
+use postgres::activitypub::PgActivityPubRepository;
+use postgres::engagement::PgEngagementRepository;
+use postgres::outbox::PgOutboxWriter;
+use postgres::remote_actor_connections::PgRemoteActorConnectionRepository;
+use postgres_federation::{PostgresApUserRepository, PostgresFederationRepository};
+use presentation::state::AppState;
+
+use crate::config::Config;
+
+/// Everything the binary needs to start serving.
+pub struct Infrastructure {
+    pub state: AppState,
+    pub ap_service: Arc<ActivityPubService>,
+}
+
+struct NoOpEventPublisher;
+
+#[async_trait]
+impl EventPublisher for NoOpEventPublisher {
+    async fn publish(&self, _e: &DomainEvent) -> Result<(), DomainError> {
+        Ok(())
+    }
+}
+
+pub async fn build(cfg: &Config) -> Infrastructure {
+    // 1. Database connection + migrations
+    let pool = PgPool::connect(&cfg.database_url)
+        .await
+        .expect("Failed to connect to database");
+    sqlx::migrate!("../adapters/postgres/migrations")
+        .run(&pool)
+        .await
+        .expect("Failed to run migrations");
+    tracing::info!("Database connected and migrations applied");
+
+    // 2. Event publisher — real NATS or no-op fallback
+    let event_publisher: Arc<dyn EventPublisher> = match &cfg.nats_url {
+        Some(url) => match async_nats::connect(url).await {
+            Ok(client) => {
+                tracing::info!("Connected to NATS at {url}");
+                if let Err(e) = nats::ensure_stream(&client).await {
+                    tracing::warn!("JetStream stream setup failed: {e} — events may be lost");
+                }
+                Arc::new(EventPublisherAdapter::new(NatsTransport::new(client)))
+            }
+            Err(e) => {
+                tracing::warn!("NATS connect failed ({e}) — falling back to no-op publisher");
+                Arc::new(NoOpEventPublisher)
+            }
+        },
+        None => {
+            tracing::info!("NATS_URL not set — using no-op event publisher");
+            Arc::new(NoOpEventPublisher)
+        }
+    };
+
+    // 3. ActivityPub federation
+    let ap_service = Arc::new(
+        ActivityPubService::new(
+            Arc::new(PostgresFederationRepository::new(pool.clone())),
+            Arc::new(PostgresApUserRepository::new(
+                pool.clone(),
+                cfg.base_url.clone(),
+            )),
+            Arc::new(ThoughtsObjectHandler::new(
+                Arc::new(PgActivityPubRepository::new(pool.clone())),
+                &cfg.base_url,
+                Some(event_publisher.clone()),
+                Arc::new(postgres::tag::PgTagRepository::new(pool.clone())),
+            )),
+            cfg.base_url.clone(),
+            cfg.allow_registration,
+            "thoughts".to_string(),
+            cfg.debug,
+            None,
+        )
+        .await
+        .expect("Failed to build ActivityPubService"),
+    );
+
+    // 4. Application state
+    let state = AppState {
+        users: Arc::new(postgres::user::PgUserRepository::new(pool.clone())),
+        thoughts: Arc::new(postgres::thought::PgThoughtRepository::new(pool.clone())),
+        likes: Arc::new(postgres::like::PgLikeRepository::new(pool.clone())),
+        boosts: Arc::new(postgres::boost::PgBoostRepository::new(pool.clone())),
+        follows: Arc::new(postgres::follow::PgFollowRepository::new(pool.clone())),
+        blocks: Arc::new(postgres::block::PgBlockRepository::new(pool.clone())),
+        tags: Arc::new(postgres::tag::PgTagRepository::new(pool.clone())),
+        api_keys: Arc::new(postgres::api_key::PgApiKeyRepository::new(pool.clone())),
+        top_friends: Arc::new(postgres::top_friend::PgTopFriendRepository::new(
+            pool.clone(),
+        )),
+        notifications: Arc::new(postgres::notification::PgNotificationRepository::new(
+            pool.clone(),
+        )),
+        remote_actors: Arc::new(postgres::remote_actor::PgRemoteActorRepository::new(
+            pool.clone(),
+        )),
+        feed: Arc::new(postgres::feed::PgFeedRepository::new(pool.clone())),
+        search: Arc::new(postgres_search::PgSearchRepository::new(pool.clone())),
+        auth: Arc::new({
+            if cfg.jwt_secret.len() < JWT_SECRET_MIN_BYTES {
+                panic!(
+                    "JWT_SECRET is {} bytes — minimum is {} bytes for HS256 security",
+                    cfg.jwt_secret.len(),
+                    JWT_SECRET_MIN_BYTES,
+                );
+            }
+            auth::JwtAuthService::new(cfg.jwt_secret.clone(), JWT_TTL_SECS)
+        }),
+        hasher: Arc::new(auth::Argon2PasswordHasher),
+        events: event_publisher,
+        outbox: Arc::new(PgOutboxWriter::new(pool.clone())) as Arc<dyn OutboxWriter>,
+        federation: ap_service.clone() as Arc<dyn domain::ports::FederationActionPort>,
+        ap_repo: Arc::new(PgActivityPubRepository::new(pool.clone())),
+        remote_actor_connections: Arc::new(PgRemoteActorConnectionRepository::new(pool.clone())),
+        federation_scheduler: ap_service.clone() as Arc<dyn domain::ports::FederationSchedulerPort>,
+        api_key_auth: Arc::new(ApiKeyServiceImpl::new(
+            Arc::new(postgres::api_key::PgApiKeyRepository::new(pool.clone())),
+        )),
+        engagement: Arc::new(PgEngagementRepository::new(pool.clone())),
+    };
+
+    Infrastructure { state, ap_service }
+}

crates/bootstrap/src/main.rs

@@ -0,0 +1,83 @@
+mod config;
+mod factory;
+
+const MS_PER_MINUTE: u64 = 60_000;
+const RATE_LIMITER_CLEANUP_INTERVAL_SECS: u64 = 60;
+
+use std::net::SocketAddr;
+use std::sync::Arc;
+use tower_http::cors::{AllowOrigin, CorsLayer};
+use tracing_subscriber::EnvFilter;
+
+#[tokio::main]
+async fn main() {
+    let cfg = config::Config::from_env();
+
+    tracing_subscriber::fmt()
+        .with_env_filter(EnvFilter::from_default_env())
+        .init();
+
+    let infra = factory::build(&cfg).await;
+
+    // CORS
+    let cors = if cfg.cors_origins.trim() == "*" {
+        CorsLayer::permissive()
+    } else {
+        let origins: Vec<http::HeaderValue> = cfg
+            .cors_origins
+            .split(',')
+            .map(|o| o.trim())
+            .filter_map(|o| o.parse().ok())
+            .collect();
+        CorsLayer::new()
+            .allow_origin(AllowOrigin::list(origins))
+            .allow_methods(tower_http::cors::Any)
+            .allow_headers(tower_http::cors::Any)
+    };
+
+    let base = presentation::routes::router()
+        .merge(infra.ap_service.router::<presentation::state::AppState>())
+        .with_state(infra.state)
+        .layer(cors);
+
+    let addr = format!("{}:{}", cfg.host, cfg.port);
+    tracing::info!("Listening on {addr}");
+    let listener = tokio::net::TcpListener::bind(&addr).await.unwrap();
+
+    if let Some(rate_limit) = cfg.rate_limit {
+        use tower_governor::{governor::GovernorConfigBuilder, GovernorLayer}; // crate: tower_governor
+
+        // per_millisecond sets the token replenishment interval.
+        // rate_limit = max requests/minute => replenish every (60000 / rate_limit) ms.
+        let ms = MS_PER_MINUTE.saturating_div(rate_limit as u64).max(1);
+        let governor_conf = Arc::new(
+            GovernorConfigBuilder::default()
+                .per_millisecond(ms)
+                .burst_size(rate_limit)
+                .use_headers()
+                .finish()
+                .expect("valid rate limit config"),
+        );
+
+        let limiter = governor_conf.limiter().clone();
+        tokio::spawn(async move {
+            let mut interval = tokio::time::interval(std::time::Duration::from_secs(
+                RATE_LIMITER_CLEANUP_INTERVAL_SECS,
+            ));
+            loop {
+                interval.tick().await;
+                limiter.retain_recent();
+            }
+        });
+
+        let app = base.layer(GovernorLayer::new(governor_conf));
+        axum::serve(
+            listener,
+            app.into_make_service_with_connect_info::<SocketAddr>(),
+        )
+        .await
+        .unwrap();
+    } else {
+        axum::serve(listener, base).await.unwrap();
+    }
+}

crates/domain/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "domain"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+test-helpers = ["dep:sha2", "dep:hex"]
+
+[dependencies]
+async-trait = { workspace = true }
+thiserror   = { workspace = true }
+uuid        = { workspace = true }
+chrono      = { workspace = true }
+serde       = { workspace = true }
+futures     = { workspace = true }
+url         = { workspace = true }
+sha2        = { version = "0.10", optional = true }
+hex         = { version = "0.4", optional = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["full"] }
+sha2  = "0.10"
+hex   = "0.4"

crates/domain/src/errors.rs

@@ -0,0 +1,21 @@
+use thiserror::Error;
+
+#[derive(Debug, Error, Clone)]
+pub enum DomainError {
+    #[error("not found")]
+    NotFound,
+    #[error("unauthorized")]
+    Unauthorized,
+    #[error("forbidden")]
+    Forbidden,
+    #[error("conflict: {0}")]
+    Conflict(String),
+    #[error("unique violation on field: {field}")]
+    UniqueViolation { field: &'static str },
+    #[error("invalid input: {0}")]
+    InvalidInput(String),
+    #[error("external service error: {0}")]
+    ExternalService(String),
+    #[error("internal error: {0}")]
+    Internal(String),
+}

crates/domain/src/events.rs

@@ -0,0 +1,86 @@
+use crate::value_objects::{BoostId, LikeId, ThoughtId, UserId};
+
+#[derive(Debug, Clone)]
+pub enum DomainEvent {
+    ThoughtCreated {
+        thought_id: ThoughtId,
+        user_id: UserId,
+        in_reply_to_id: Option<ThoughtId>,
+    },
+    ThoughtDeleted {
+        thought_id: ThoughtId,
+        user_id: UserId,
+    },
+    ThoughtUpdated {
+        thought_id: ThoughtId,
+        user_id: UserId,
+    },
+    LikeAdded {
+        like_id: LikeId,
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    LikeRemoved {
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    BoostAdded {
+        boost_id: BoostId,
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    BoostRemoved {
+        user_id: UserId,
+        thought_id: ThoughtId,
+    },
+    FollowRequested {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    FollowAccepted {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    FollowRejected {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    Unfollowed {
+        follower_id: UserId,
+        following_id: UserId,
+    },
+    UserBlocked {
+        blocker_id: UserId,
+        blocked_id: UserId,
+    },
+    UserUnblocked {
+        blocker_id: UserId,
+        blocked_id: UserId,
+    },
+    UserRegistered {
+        user_id: UserId,
+    },
+    ProfileUpdated {
+        user_id: UserId,
+    },
+    MentionReceived {
+        thought_id: ThoughtId,
+        mentioned_user_id: UserId,
+        author_user_id: UserId,
+    },
+}
+
+pub struct EventEnvelope {
+    pub event: DomainEvent,
+    pub delivery_count: u64,
+    pub ack: Box<dyn Fn() + Send + Sync>,
+    pub nack: Box<dyn Fn() + Send + Sync>,
+}
+impl std::fmt::Debug for EventEnvelope {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("EventEnvelope")
+            .field("event", &self.event)
+            .field("delivery_count", &self.delivery_count)
+            .finish()
+    }
+}

crates/domain/src/hashtag.rs

@@ -0,0 +1,139 @@
+use std::collections::HashSet;
+
+/// A hashtag extracted from content.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct Hashtag {
+    /// Original casing, e.g. "Rust"
+    pub raw: String,
+    /// Lowercased, e.g. "rust" — used for DB lookups
+    pub normalized: String,
+    /// "tags/rust" — callers prepend base_url
+    pub url_slug: String,
+    /// "#rust" — used directly in AP tag array
+    pub ap_name: String,
+}
+
+/// Extract hashtags from content using a char-by-char scan.
+///
+/// Rules:
+/// - Tag starts after a bare `#` followed immediately by an alphanumeric char.
+/// - Tag chars: `[A-Za-z0-9_]`.
+/// - Deduplicated case-insensitively; first occurrence wins.
+/// - Returned in order of first appearance.
+pub fn extract(content: &str) -> Vec<Hashtag> {
+    let mut seen: HashSet<String> = HashSet::new();
+    let mut tags: Vec<Hashtag> = Vec::new();
+    let mut chars = content.char_indices().peekable();
+
+    while let Some((_, c)) = chars.next() {
+        if c == '#'
+            && chars
+                .peek()
+                .map(|(_, nc)| nc.is_alphanumeric())
+                .unwrap_or(false)
+        {
+            let raw: String = chars
+                .by_ref()
+                .take_while(|(_, nc)| nc.is_alphanumeric() || *nc == '_')
+                .map(|(_, nc)| nc)
+                .collect();
+
+            if raw.is_empty() {
+                continue;
+            }
+
+            let normalized = raw.to_lowercase();
+            if seen.insert(normalized.clone()) {
+                tags.push(Hashtag {
+                    url_slug: format!("tags/{}", normalized),
+                    ap_name: format!("#{}", normalized),
+                    raw,
+                    normalized,
+                });
+            }
+        }
+    }
+
+    tags
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn names(tags: &[Hashtag]) -> Vec<&str> {
+        tags.iter().map(|h| h.normalized.as_str()).collect()
+    }
+
+    #[test]
+    fn basic() {
+        let tags = extract("Hello #world and #Rust!");
+        assert_eq!(names(&tags), ["world", "rust"]);
+    }
+
+    #[test]
+    fn fields() {
+        let tags = extract("#Rust");
+        assert_eq!(tags.len(), 1);
+        let h = &tags[0];
+        assert_eq!(h.raw, "Rust");
+        assert_eq!(h.normalized, "rust");
+        assert_eq!(h.url_slug, "tags/rust");
+        assert_eq!(h.ap_name, "#rust");
+    }
+
+    #[test]
+    fn dedup_case_insensitive() {
+        let tags = extract("#rust #Rust #RUST");
+        assert_eq!(names(&tags), ["rust"]);
+        assert_eq!(tags[0].raw, "rust"); // first occurrence wins
+    }
+
+    #[test]
+    fn deduplicates_non_adjacent() {
+        // The old algorithm used Vec::dedup() which only removes adjacent duplicates.
+        // Using HashSet silently fixed this bug. This test documents the fix.
+        let tags = extract("#a #b #a");
+        assert_eq!(tags.len(), 2);
+        assert_eq!(tags[0].normalized, "a");
+        assert_eq!(tags[1].normalized, "b");
+    }
+
+    #[test]
+    fn mid_word_extracted() {
+        // `text#tag` — `#` not preceded by whitespace is still matched by the
+        // char-by-char scan (the old algorithm didn't require whitespace before `#`).
+        // This test documents the authoritative behaviour: mid-word tags ARE extracted.
+        let tags = extract("text#tag");
+        assert_eq!(names(&tags), ["tag"]);
+    }
+
+    #[test]
+    fn hash_only_ignored() {
+        assert!(extract("# lone hash").is_empty());
+    }
+
+    #[test]
+    fn trailing_punctuation_excluded() {
+        // punctuation after tag terminates the tag, not included
+        let tags = extract("#rust.");
+        assert_eq!(names(&tags), ["rust"]);
+    }
+
+    #[test]
+    fn underscore_allowed() {
+        let tags = extract("#hello_world");
+        assert_eq!(names(&tags), ["hello_world"]);
+    }
+
+    #[test]
+    fn empty_content() {
+        assert!(extract("").is_empty());
+    }
+
+    #[test]
+    fn order_of_appearance() {
+        let tags = extract("#b #a #c");
+        assert_eq!(names(&tags), ["b", "a", "c"]);
+    }
+}

crates/domain/src/lib.rs

@@ -0,0 +1,9 @@
+pub mod errors;
+pub mod events;
+pub mod hashtag;
+pub mod models;
+pub mod ports;
+pub mod value_objects;
+
+#[cfg(any(test, feature = "test-helpers"))]
+pub mod testing;