ActivityPub Federation Protocol

This skill provides understanding of the ActivityPub protocol specification and how federation works.

For supported features and compatibility: See FEDERATION.md for the complete list of implemented FEPs, supported standards, and federation compatibility details.

For implementation details: See AGENTS.md for transformers, handlers, and PHP code patterns.

Core Concepts

Three Building Blocks

1. Actors - Users/accounts in the system
   • Each actor has a unique URI
   • Required: inbox, outbox
   • Optional: followers, following, liked