- OStatus
Suite of federation protocols- Salmon
Delivery of targeted events to users - Portable Contacts
Encoding profile information in Atom - Atom
Representing user feeds - Atom ActivityStreams
Encoding rich social post metadata - Atom Threading
Encoding chains of conversations - WebSub (formerly PubSubHubbub)
Broadcasting of real-time updates to followers
- Salmon
- WebFinger
User-on-domain lookups - HTTP Signatures
Server-to-server authentication of requests - ActivityPub
Federation protocol