AT Protocol
The AT Protocol (atproto) is an open, federated networking protocol for social applications, originally developed by Bluesky Social PBC and the Bluesky team. It defines a decentralized architecture where user identity and data are portable across providers, anchored in DIDs, signed records, and content-addressed storage. The protocol is composed of independently operable services — Personal Data Servers (PDS), Relays (firehose aggregators), and AppViews (read-side indexers) — that communicate using XRPC and exchange records described by Lexicon schemas. Bluesky (bsky.app) is the reference application built on AT Protocol, but the protocol is designed for any social or social-adjacent application that wants user-owned identity, portable data, and an open federation model. Official and community SDKs exist for TypeScript, Go, Python, Rust, Dart, Swift, C#/.NET, Ruby, PHP, and more, and the full lexicon, network topology, and reference implementations are open source.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles AT Protocol the way a machine reads it — 21 machine-readable artifacts across 12 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — AT Protocol scores 45.4/100 (developing), with a separate agent-readiness read of 54/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile AT Protocol
Each block below is one kind of artifact we hold for AT Protocol. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 12
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
AT Protocol XRPC API
XRPC is the AT Protocol's HTTP-based remote procedure call layer. All protocol interactions — querying records, writing records, subscribing to streams, resolving identity, mode...
AT Protocol Lexicon Schemas
Lexicon is the schema definition language for AT Protocol. Every record type, XRPC method, and event subscription on the network is described by a Lexicon document, which acts a...
Personal Data Server (PDS) API
The PDS hosts a user's repository of signed records and exposes the com.atproto.* XRPC methods for account creation, authentication, record CRUD, blob upload, and repository syn...
AT Protocol Relay & Firehose
The Relay aggregates the com.atproto.sync.subscribeRepos firehose across PDS hosts and re-broadcasts the combined event stream over WebSocket. AppViews and indexers subscribe to...
Bluesky AppView API
The Bluesky AppView indexes the firehose and exposes the app.bsky.* XRPC methods that the Bluesky client (and any compatible client) uses to render timelines, threads, profiles,...
AT Protocol Identity (DID & Handles)
Identity in AT Protocol is anchored in DIDs (did:plc or did:web), with human-readable handles resolved through DNS TXT records or well-known HTTP endpoints. The protocol specifi...
AT Protocol Actor API
Bluesky actor profiles (app.bsky.actor.*)
AT Protocol Feed API
Bluesky feeds, posts, and threads (app.bsky.feed.*)
AT Protocol Graph API
Follow, mute, and block graph (app.bsky.graph.*)
AT Protocol Identity API
DID and handle resolution (com.atproto.identity.*)
AT Protocol Repo API
Repository record CRUD (com.atproto.repo.*)
AT Protocol Server API
Session and account management (com.atproto.server.*)
Scroll within the panel for all 12 ·
Open Collections 1
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
AT Protocol XRPC API
OPEN COLLECTIONPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
At Protocol Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
At Protocol Finops
FINOPSEvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
AT Protocol Firehose & Event Streams
AsyncAPI definition for the AT Protocol event subscription surface. AT Protocol defines streaming endpoints as Lexicon "subscription" types, served over WebSocket using length-p...
ASYNCAPISpectral Rules 1
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
AT Protocol API Rules
SPECTRALSecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for AT Protocol — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Documentation 4
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Build 2
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Learn 1
Tutorials, courses, talks, and written guidance
Company 3
The organization behind the API
Other 1
Properties that don't map to a standard resource type
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