How It Works
AtProto (AT Protocol)
An open, federated protocol for social networking — the technical foundation of Bluesky. Instead of one company owning the network, many servers (PDSes) host user data, and relays aggregate it into a shared stream anyone can read or build on. User accounts are portable: you can move between providers without losing your posts, follows or social graph.
Origin
Created by Bluesky Social PBC, originally as “ADX” in spring 2022 and renamed the Authenticated Transfer Protocol in October 2022. The initial blog post by the Bluesky team described account portability, algorithmic choice and interoperation as its goals. An earlier name, “Bluesky,” came from a Twitter (later X) initiative announced in 2019; Bluesky became an independent company in 2022.