Leaf, ATProto and ActivityPub

The article presents Leaf, an experimental peer-to-peer federation protocol built on Willow by the Weird project, as a design that can behave like either ATProto or ActivityPub while adding local-first features and data ownership. It explains that Leaf stores user data in Subspaces built from Entities with hierarchical paths, and that subspaces can replicate locally, sync peer-to-peer, and use permissions for private data. For schemas, Leaf combines statically typed components on each entity, sitting between RDF's dynamic model and ATProto's Lexicon. Leaf identifies schemas by content hashes so they cannot be changed after issue. The author says the project has no interest in building a Bluesky- or Mastodon-style microblog app.