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What k-ap Does (and Doesn't Do)

Gabriel Kaszewski edited this page 2026-05-29 02:08:34 +00:00

Table of Contents

• What k-ap Does (and Doesn't Do)
• What k-ap owns
• What you own
• The trait boundary
• Why not domain-specific?

What k-ap Does (and Doesn't Do)

k-ap is a protocol layer, not a social platform. It handles the ActivityPub plumbing so you can focus on your domain — content, users, UI, business logic.

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What k-ap owns

Responsibility	Detail
HTTP signature verification	All inbound inbox requests are verified before any handler is called
Inbox routing and dispatch	POST /inbox and POST /users/{id}/inbox — dedup, activity dispatch
Outbox pagination	GET /users/{id}/outbox — cursor-based OrderedCollection
Featured (pinned posts) collection	GET /users/{id}/featured — OrderedCollection from your ApContentReader
WebFinger	GET /.well-known/webfinger — JRD with aliases
NodeInfo	GET /.well-known/nodeinfo redirect + GET /nodeinfo/2.0
HTTP signature creation	Signs all outbound delivery requests
Follower graph management	Follow, Accept, Reject, Undo(Follow), Move migration
Activity deduplication	Every inbound activity checked via ActivityRepository before processing
Broadcast delivery	Resolves follower inboxes, deduplicates, signs, delivers
Remote actor cache	Fetches and caches remote actor JSON via ActorRepository

What you own

Responsibility	Detail
Content types	What goes inside Create/Update — Note, Article, Video, etc.
User storage	Creating, finding, and persisting local users
Database layer	All seven traits are your data access layer
Actor/followers/following HTTP routes	Need content negotiation — k-ap provides helpers, you own the route
UI and application logic	Feed generation, notifications, search, etc.
Blocklist population	k-ap checks the blocklist; you populate it
Job queue	Optional — k-ap spawns in-process by default; you wire it up for workers

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The trait boundary

k-ap calls into your code through seven focused traits. You implement them against whatever database or storage layer you use. k-ap never touches storage directly.

k-ap library
    │
    ├── calls ActivityRepository  (you implement)
    ├── calls FollowRepository    (you implement)
    ├── calls ActorRepository     (you implement)
    ├── calls BlocklistRepository (you implement)
    ├── calls ApUserRepository    (you implement)
    ├── calls ApContentReader     (you implement)
    └── calls ApObjectHandler     (you implement)

Each trait has a focused, narrow scope. See The Seven Traits for full detail.

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Why not domain-specific?

ActivityPub federates activities, not content types. A Create(Note) from Mastodon and a Create(Article) from a blog platform have the same activity structure — only the wrapped object differs. k-ap handles the activity layer and lets you decide what your objects look like.

This means k-ap works equally well for microblogging, movie logging, book tracking, music sharing, or any other domain.

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