ATProto was developed by Bluesky as an open social protocol.
The AT Protocol is a networking technology created to power the next generation of social applications. The initial reference application,Ā bsky.app,provides a global-scale microblogging experience.
Creation of an IETF working group is in progress, as of late 2025 / early 2026.
Protocol Overview
TheĀ Authenticated Transfer Protocol, akaĀ 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
Specification
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
PDS
Personal Data Server. Similar in concept to Personal Data Store, except this is the software server and can host multiple user accounts.
- Bluesky Typescript Implementation bluesky-social/pds
- Related PDS posts on the community forum
See also ATProto Community Resources
Notes mentioning this note
At protocol community fund
A project hosted by [[Raft Foundation]] to pool funds and provide support for AT Protocol community initiatives, commons infrastructure, and...
Atproto community wiki
A [[WikiJS]] powered wiki for the [[ATProtocol]] community. I started this after the [[ATmosphereConf]] to have a place to put...
Atproto and mcp both picking oauth
[[ATProtocol]] and [[MCP]] are both picking OAuth as their authorization layer. In both scenarios, the need is for a wide...
Atprotocol dev
A blog, newsletter, and event series following the development of protocol apps building on top ofĀ [[ATProtocol]]. This follows my belief...
Atmosphereconf
I'm one of the organizers for this [[ATProtocol]] community conference, March 22nd & 23rd in Seattle, Washington. Other organizers include...
EuroCloud to App Liftoff in the ATmosphere
I gave this talk at [[EuroSky Live]]. My goal was to do a survey of all of the things that...
Beyond Microblogging: AT Protocol for Building Unique Social Apps
I gave this presentation at [[Fedicon]] 2025 in Vancouver. My goal was not to do a protocol deep dive, but...
Blacksky
Building the Black social layer for the decentralized web. Blacksky is providing a platform toĀ amplify, protect, and moderateĀ Black content so...
Bluesky custom feeds for premium content
[[Bluesky]] already has built in support for [[Bluesky#Custom Feeds custom feeds]]. Could this be used to create premium content feeds?...
Bluesky
Weāre building theĀ AT Protocol, a new foundation for public conversation and social networking which gives creators independence from platforms, developers...
About Boris Mann
Hi, I'm Boris Mann! Some things I've been thinking about recently: [[pooling capital and collaboration]] [[self-hosting is selfish]] [[No Jobs...
Bryan newbold
As of Spring 2023 I live in Seattle, at theĀ ELSĀ household. I love the volcanoes in this region: climbing them, biking...
Chaoti.ca
This is [[walkah]]'s long time domain name that he has now thought of a project to put there. A personal...
Community search engine
Community Search Engines are an approach to build highly relevant search indexes and collaborative content spaces for communities. The interface...
Cruising the atmosphere together
Presentation by [[Bryan Newbold]] about [[ATProtocol]] as of Summer 2024, at [[LOCALHOST Social]]
PDF š
Did plc
DID PLC is a self-authenticating [[DID]]Ā which is strongly-consistent, recoverable, and allows for key rotation. An example DID is:Ā did:plc:ewvi7nxzyoun6zhxrhs64oiz Control over...
Eurosky
Part of [[Free Our Feeds]], building [[ATProtocol]] commons infrastructure for Europe Eurosky is building the future of social mediaāopen, pluralistic,...
Feedback on federating ghost
A survey asking for feedback on Federating [[Ghost]] ActivityPub support is one of our most requested features of all time,...
Feeds
Journals are mostly lapsed as of mid 2025. Micro-blog sized updates referencing Note updates or interesting links and articles bmannconsulting.com/journal.xml...
Free our feeds
Initiative to form a foundation and run a relay for [[ATProtocol]] so that itās not just [[Bluesky]] running the bulk...
Germ network
Building an [[MLS]] compliant e2ee messaging system, with [[Autonomous Communicator Protocol]] and an open source Swift implementation. Working on E2EE...
Groundmist
Groundmist is a series of experiments using [[Automerge]] for local first editing and private sharing, combined with [[ATProtocol]] for login...
Localhost social
The Thursday social part of [[LOCALHOST]] on July 25th, 2024, at Osito on W Hastings. Luma page: https://lu.ma/b9p075ag IETF We...
LOCALHOST Vancouver
Organized by me, [[Dawn Walker]], [[Chad Kohalyk]], and the [[DWebYVR]] community. Full calendar Ā» IETF Hackathon Saturday July 20th and...
Leaflet
Leaflet is a tool for writing and publishing together. It features a block based editor and is powered by [[ATProtocol]]...
Lexicon
Data type definitions for [[ATProtocol]] for different types of apps. Some of the existing ones include: [[WhiteWind]] long form blogging...
Meeting notes april 1st, 2025
Quick catch up with [[Sam Gbafa]], founder of [[TinyCloud]], who I've worked with hacking on various local first / user...
Migrating pds account with goat
[[Bryan Newbold]]'s write up on how to move your [[ATProtocol]] account between [[PDS]]. The entire meat of the article is,...
Noosphere
The Noosphere ProtocolĀ is part of an effort to bootstrapĀ a new kind of content web. Noosphere, like its namesake, is a...
Note clips
Notes on making a cross-tool drag and drop capability. What if you could open your [[Digital Garden]] / Second Brain...
Now
It's January 2026, and I've had a rough couple of months. spent most of December and half of January in...
Open social daus
If we hope to see [[Open Social Protocols]] succeed ā that is, be available and widely adopted as open protocols...
Open social protocols
The three protocols that I think are going to continue to grow and be adopted are: [[ActivityPub]]: Meta building Threads...
Personal Data Server
Personal Data Server is abbreviated as PDS. The more generic [[Personal Data Store]] is a non-protocol specific label for the...
Personal data store
General term for data that is owned by the user, and attached to different apps. This is in contrast to...
Personal notes & publishing stack
The base line tool that I am looking for to anchor [[Community Search Engine]] is a multi-player personal notes &...
Proto apps
Iām adopting the term āProtocol Appsā from David Phelpsā [[Proto-App Thesis]]. In short, the thesis says that large, mass market...
The Proto-App Thesis
even the strongest case for apps is, at heart, a case for protocols. It is not a new argument. Joel...
The Revolution Will Be Decentralized
By [[Joan Westenberg]] The reality is that these trends arenāt merely parallelāāātheyāre symbiotic. Each creates conditions that accelerate the other,...
Semble
A social bookmarking app built by [[Cosmik Network]] as one of their first [[ATProtocol]] applications.
Smoke signal
A modern event and RSVP management system built on top of the powerful, people-centricĀ [[ATProtocol]].
Built by [[Nick Gerakines]]
Tapbots
Original makers of the Tweetbot [[Twitter]] client, now making [[Ivory]] for [[Mastodon]], and the forthcoming [[Phoenix]] for [[ATProtocol]].
Threadstorm builder
I wrote up the design for this many years ago now, when I called it a Tweetstorm Builder and Blog....
Unnamed good pod
A podcast that I did with Serena & Max from [[1RG]]. Using [[Castopod]] hosted at [[CoSocial]]. EP01: Introducing Unnamed Good...
Using semble for link blogging
Iām an advisor to the [[Cosmik Network]] team who are building [[Semble]], a social bookmarking app built on [[ATProtocol]]. Currently...
Vancouver hack day
Iām organizing a couple hack days in Vancouver as part of the [[DWebYVR]] group. Whatās a hack day? Not āhackathonsā...
Web3
My definition of web3 from a technical perspective is that it is composed of self-verifying data structures, cryptography, and distributed...
Atproto Browser
The atproto-browser lets you browse records in your user account on [[ATProtocol]], as well as see various other things in...
Did web
Unofficial DraftĀ 31 July 2024 Abstract DIDs that target a distributed ledger face significant practical challenges in bootstrapping enough meaningful trusted...