diff --git a/k-tv-backend/api/src/poller.rs b/k-tv-backend/api/src/poller.rs
index 17ae9f5..7b5ca02 100644
--- a/k-tv-backend/api/src/poller.rs
+++ b/k-tv-backend/api/src/poller.rs
@@ -300,6 +300,8 @@ mod tests {
                 series_name: None,
                 season_number: None,
                 episode_number: None,
+                thumbnail_url: None,
+                collection_id: None,
             },
             source_block_id: Uuid::new_v4(),
         }
diff --git a/k-tv-backend/domain/src/entities.rs b/k-tv-backend/domain/src/entities.rs
index 1a49b8d..aa5a7cb 100644
--- a/k-tv-backend/domain/src/entities.rs
+++ b/k-tv-backend/domain/src/entities.rs
@@ -346,6 +346,10 @@ pub struct MediaItem {
     pub season_number: Option<u32>,
     /// For episodes: episode number within the season (1-based).
     pub episode_number: Option<u32>,
+    /// Provider-served thumbnail image URL, populated if available.
+    pub thumbnail_url: Option<String>,
+    /// Provider-specific collection this item belongs to.
+    pub collection_id: Option<String>,
 }
 
 /// A fully resolved 7-day broadcast program for one channel.
diff --git a/k-tv-backend/domain/src/events.rs b/k-tv-backend/domain/src/events.rs
index 02f1686..e7ecc3a 100644
--- a/k-tv-backend/domain/src/events.rs
+++ b/k-tv-backend/domain/src/events.rs
@@ -58,6 +58,8 @@ mod tests {
                 series_name: None,
                 season_number: None,
                 episode_number: None,
+                thumbnail_url: None,
+                collection_id: None,
             },
             source_block_id: Uuid::new_v4(),
         }
diff --git a/k-tv-backend/domain/src/lib.rs b/k-tv-backend/domain/src/lib.rs
index aaefa18..4f61e2c 100644
--- a/k-tv-backend/domain/src/lib.rs
+++ b/k-tv-backend/domain/src/lib.rs
@@ -6,6 +6,7 @@
 pub mod entities;
 pub mod errors;
 pub mod iptv;
+pub mod library;
 pub mod ports;
 pub mod repositories;
 pub mod services;
@@ -19,5 +20,10 @@ pub use events::DomainEvent;
 pub use ports::{Collection, IMediaProvider, IProviderRegistry, ProviderCapabilities, SeriesSummary, StreamingProtocol, StreamQuality};
 pub use repositories::*;
 pub use iptv::{generate_m3u, generate_xmltv};
+pub use library::{
+    ILibraryRepository, LibraryCollection, LibraryItem, LibrarySearchFilter,
+    LibrarySyncAdapter, LibrarySyncLogEntry, LibrarySyncResult,
+};
+pub use repositories::IAppSettingsRepository;
 pub use services::{ChannelService, ScheduleEngineService, UserService};
 pub use value_objects::*;
diff --git a/k-tv-backend/domain/src/library.rs b/k-tv-backend/domain/src/library.rs
new file mode 100644
index 0000000..cc0ce96
--- /dev/null
+++ b/k-tv-backend/domain/src/library.rs
@@ -0,0 +1,156 @@
+//! Library domain types and ports.
+
+use async_trait::async_trait;
+
+use crate::{ContentType, DomainResult, IMediaProvider};
+
+/// A media item stored in the local library cache.
+#[derive(Debug, Clone)]
+pub struct LibraryItem {
+    pub id: String,
+    pub provider_id: String,
+    pub external_id: String,
+    pub title: String,
+    pub content_type: ContentType,
+    pub duration_secs: u32,
+    pub series_name: Option<String>,
+    pub season_number: Option<u32>,
+    pub episode_number: Option<u32>,
+    pub year: Option<u16>,
+    pub genres: Vec<String>,
+    pub tags: Vec<String>,
+    pub collection_id: Option<String>,
+    pub collection_name: Option<String>,
+    pub collection_type: Option<String>,
+    pub thumbnail_url: Option<String>,
+    pub synced_at: String,
+}
+
+/// A collection summary derived from synced library items.
+#[derive(Debug, Clone)]
+pub struct LibraryCollection {
+    pub id: String,
+    pub name: String,
+    pub collection_type: Option<String>,
+}
+
+/// Result of a single provider sync run.
+#[derive(Debug, Clone)]
+pub struct LibrarySyncResult {
+    pub provider_id: String,
+    pub items_found: u32,
+    pub duration_ms: u64,
+    pub error: Option<String>,
+}
+
+/// Log entry from library_sync_log table.
+#[derive(Debug, Clone)]
+pub struct LibrarySyncLogEntry {
+    pub id: i64,
+    pub provider_id: String,
+    pub started_at: String,
+    pub finished_at: Option<String>,
+    pub items_found: u32,
+    pub status: String,
+    pub error_msg: Option<String>,
+}
+
+/// Filter for searching the local library.
+#[derive(Debug, Clone)]
+pub struct LibrarySearchFilter {
+    pub provider_id: Option<String>,
+    pub content_type: Option<ContentType>,
+    pub series_names: Vec<String>,
+    pub collection_id: Option<String>,
+    pub genres: Vec<String>,
+    pub decade: Option<u16>,
+    pub min_duration_secs: Option<u32>,
+    pub max_duration_secs: Option<u32>,
+    pub search_term: Option<String>,
+    pub offset: u32,
+    pub limit: u32,
+}
+
+impl Default for LibrarySearchFilter {
+    fn default() -> Self {
+        Self {
+            provider_id: None,
+            content_type: None,
+            series_names: vec![],
+            collection_id: None,
+            genres: vec![],
+            decade: None,
+            min_duration_secs: None,
+            max_duration_secs: None,
+            search_term: None,
+            offset: 0,
+            limit: 50,
+        }
+    }
+}
+
+/// Port: sync one provider's items into the library repo.
+/// DB writes are handled entirely inside implementations — no pool in the trait.
+#[async_trait]
+pub trait LibrarySyncAdapter: Send + Sync {
+    async fn sync_provider(
+        &self,
+        provider: &dyn IMediaProvider,
+        provider_id: &str,
+    ) -> LibrarySyncResult;
+}
+
+/// Port: read/write access to the persisted library.
+#[async_trait]
+pub trait ILibraryRepository: Send + Sync {
+    async fn search(&self, filter: &LibrarySearchFilter) -> DomainResult<(Vec<LibraryItem>, u32)>;
+    async fn get_by_id(&self, id: &str) -> DomainResult<Option<LibraryItem>>;
+    async fn list_collections(&self, provider_id: Option<&str>) -> DomainResult<Vec<LibraryCollection>>;
+    async fn list_series(&self, provider_id: Option<&str>) -> DomainResult<Vec<String>>;
+    async fn list_genres(&self, content_type: Option<&ContentType>, provider_id: Option<&str>) -> DomainResult<Vec<String>>;
+    async fn upsert_items(&self, provider_id: &str, items: Vec<LibraryItem>) -> DomainResult<()>;
+    async fn clear_provider(&self, provider_id: &str) -> DomainResult<()>;
+    async fn log_sync_start(&self, provider_id: &str) -> DomainResult<i64>;
+    async fn log_sync_finish(&self, log_id: i64, result: &LibrarySyncResult) -> DomainResult<()>;
+    async fn latest_sync_status(&self) -> DomainResult<Vec<LibrarySyncLogEntry>>;
+    async fn is_sync_running(&self, provider_id: &str) -> DomainResult<bool>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn library_item_id_uses_double_colon_separator() {
+        let item = LibraryItem {
+            id: "jellyfin::abc123".to_string(),
+            provider_id: "jellyfin".to_string(),
+            external_id: "abc123".to_string(),
+            title: "Test Movie".to_string(),
+            content_type: crate::ContentType::Movie,
+            duration_secs: 7200,
+            series_name: None,
+            season_number: None,
+            episode_number: None,
+            year: Some(2020),
+            genres: vec!["Action".to_string()],
+            tags: vec![],
+            collection_id: None,
+            collection_name: None,
+            collection_type: None,
+            thumbnail_url: None,
+            synced_at: "2026-03-19T00:00:00Z".to_string(),
+        };
+        assert!(item.id.contains("::"));
+        assert_eq!(item.provider_id, "jellyfin");
+    }
+
+    #[test]
+    fn library_search_filter_defaults_are_empty() {
+        let f = LibrarySearchFilter::default();
+        assert!(f.genres.is_empty());
+        assert!(f.series_names.is_empty());
+        assert_eq!(f.offset, 0);
+        assert_eq!(f.limit, 50);
+    }
+}
diff --git a/k-tv-backend/domain/src/repositories.rs b/k-tv-backend/domain/src/repositories.rs
index b1a3cbb..50000a9 100644
--- a/k-tv-backend/domain/src/repositories.rs
+++ b/k-tv-backend/domain/src/repositories.rs
@@ -180,3 +180,14 @@ pub trait TranscodeSettingsRepository: Send + Sync {
     /// Persist the cleanup TTL (upsert — always row id=1).
     async fn save_cleanup_ttl(&self, hours: u32) -> DomainResult<()>;
 }
+
+/// Repository port for general admin settings (app_settings table).
+#[async_trait]
+pub trait IAppSettingsRepository: Send + Sync {
+    /// Get a setting value by key. Returns None if not set.
+    async fn get(&self, key: &str) -> DomainResult<Option<String>>;
+    /// Set a setting value (upsert).
+    async fn set(&self, key: &str, value: &str) -> DomainResult<()>;
+    /// Get all settings as (key, value) pairs.
+    async fn get_all(&self) -> DomainResult<Vec<(String, String)>>;
+}
diff --git a/k-tv-backend/infra/src/jellyfin/mapping.rs b/k-tv-backend/infra/src/jellyfin/mapping.rs
index 18c353f..ebea93d 100644
--- a/k-tv-backend/infra/src/jellyfin/mapping.rs
+++ b/k-tv-backend/infra/src/jellyfin/mapping.rs
@@ -31,5 +31,7 @@ pub(super) fn map_jellyfin_item(item: JellyfinItem) -> Option<MediaItem> {
         series_name: item.series_name,
         season_number: item.parent_index_number,
         episode_number: item.index_number,
+        thumbnail_url: None,
+        collection_id: None,
     })
 }
diff --git a/k-tv-backend/infra/src/local_files/provider.rs b/k-tv-backend/infra/src/local_files/provider.rs
index bbdc669..d308494 100644
--- a/k-tv-backend/infra/src/local_files/provider.rs
+++ b/k-tv-backend/infra/src/local_files/provider.rs
@@ -51,6 +51,8 @@ fn to_media_item(id: MediaItemId, item: &LocalFileItem) -> MediaItem {
         series_name: None,
         season_number: None,
         episode_number: None,
+        thumbnail_url: None,
+        collection_id: None,
     }
 }