Developed by Bluesky

The AT Protocol is a networking technology created to power the next generation of social applications. The initial reference application,,provides a global-scale microblogging experience.

Protocol Overview

The Authenticated Transfer Protocol, aka atproto, is a federated protocol for large-scale distributed social applications. This document will introduce you to the ideas behind the AT Protocol.

From the Protocol Overview


The Authenticated Transfer Protocol (AT Protocol or atproto) is a generic federated protocol for building open social media applications. Some recurring themes and features are:

  • self-authenticating data and identity, allowing seamless account migrations and redistribution of content
  • design for "big world" use cases, scaling to billions of accounts
  • delegated authority over application-layer schemas and aggregation infrastructure
  • re-use of existing data models from the dweb protocol family and network primitives from the web platform

From the Specification

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