Bluesky's ATProto adds 'spaces,' bringing gated non-public data to a public network

Bluesky has shipped an alpha of ATProto spaces, the protocol’s first mechanism for storing data that isn’t broadcast to the whole network. Until now every record on ATProto — posts, follows, likes, blocks — has been public by design, collated through an open firehose anyone can tap. That model powers apps like Bluesky and Tangled but rules out settings, private bookmarks, member-only forums, and subscription publishing. A space behaves like a miniature ATProto network that a ‘space authority’ (itself just a DID) gates to specific DIDs, with records kept in per-space permissioned repos on the author’s PDS. Sizes range from single-member spaces for drafts and settings up to communities of millions, and because spaces skip the relay, apps sync directly from PDS hosts and get lighter-weight real-time sync.

The key caveat: spaces grant access control, not confidentiality. Data isn’t encrypted, so anyone with access to a space can read it — the alpha explicitly warns against uploading sensitive information given no security review, no backups, and destructive migrations. Bluesky is providing a hosted sandbox PDS, alpha TypeScript SDKs, a tagged Docker image for self-hosting, and a sample app (bulletin.my) where mutuals leave sticky notes on a follower-gated board. Everything is unstable, with weekly Thursday updates and breaking changes expected; the sandbox will be wiped at the end of the alpha.

The significance is architectural. Spaces preserve ATProto’s core promises — portable identity, interoperable data, and permissionless participation — while extending them beyond fully public data, which is the main structural limitation that has kept certain product categories off the network. Notably, several independent implementations (two Rust PDSes, a Zig PDS, and an AppView framework) are already building against the proposed spec, a real-world signal that ATProto is maturing toward a multi-vendor protocol rather than a single company’s stack.