AT Protocol

AT Protocol

The AT Protocol is a protocol and set of open standards for decentralized publishing and distribution of self-authenticating data within the social web. It serves as the technical foundation of the Bluesky social network, originally developed as a reference implementation for the protocol, as well as an ecosystem of interoperable social applications and services collectively referred to as the ATmosphere.

Authenticated Transfer: Architecture Overview

Authenticated Transfer (AT) is a collection of protocol components that together provide a generic framework for interoperable social web applications, using global aggregations of interlinked, self-certifying data records. This informational document provides an overview of the entire system, as implemented in late 2025. Some of those components may be in scope as work for the IETF, while other components may not. Many components are general-purpose and may find use outside of the context of AT. The intent of this document is to provide context for how all the components can fit together for certain use cases.

The AT Protocol | Bluesky

The AT Protocol (Authenticated Transfer Protocol, or atproto) is a standard for public conversation and an open-source framework for building social apps.

AT Protocol - AT Protocol

Specification for the Authenticated Transfer Protocol (AT Protocol)

Protocol Overview - AT Protocol

An introduction to the AT Protocol.

AT Protocol - AT Protocol

The AT Protocol is an open, decentralized, and high-performance network for building social applications.

Streaming Data - AT Protocol Docs - AT Protocol

Synchronizing and streaming data from the AT Protocol.

Blogging on the open social web - and more exciting features - pckt - Dev Journal

ATmosphere — referring to the growing ecosystem of applications built on the AT Protocol, a federated protocol for open social platforms. Not to be confused ...

Federation Architecture | Bluesky

The AT Protocol is made up of a bunch of pieces that stack together. Federation means that anyone can run the parts that make up the AT Protocol themselves, such as their own server.

cometsh/atex

An Elixir toolkit for the AT Protocol.

The AT Stack - AT Protocol Docs - AT Protocol

Components of the AT Protocol Stack.

Auth - AT Protocol Docs - AT Protocol

Auth for AT Protocol application developers.

A peer to peer community platform built on the AT Protocol

OAuth for AT Protocol | Bluesky

We are very happy to release the initial specification of OAuth for AT Protocol! This is expected to be the primary authentication and authorization system between atproto client apps and PDS instances going forward, replacing the current flow using App Passwords and createSession over time.