# AT Protocol

**Canonical:** https://apis.io/providers/atproto/  
**Website:** https://atproto.com/  
**APIs profiled:** 9

AT Protocol (Authenticated Transfer Protocol) is an open, federated social networking protocol developed by Bluesky Social PBC that powers the Bluesky social network and its 40M+ users. The protocol defines a public HTTP API surface via XRPC (cross-resolver protocol calls) organized under Lexicon schemas that cover identity (DIDs and handles), repository management, feed generation, labeling, and moderation. Developers can tap into a public firehose WebSocket event stream without API keys, and write operations use OAuth 2.0 or JWT bearer tokens for authentication. All data is stored in user-owned signed repositories and is 100% publicly accessible, making the protocol suitable for building social apps, feed generators, labelers, and bots.

## Kin Score — 45.8 / 100 (developing)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 45.8).

| Facet | Score |
|---|---|
| Discoverability | 74.1 |
| Contract Quality | 66.3 |
| Governance | 9.8 |
| Contract Governance | 9.8 |
| Operational Transparency | 50.0 |
| Developer Ergonomics | 31.0 |
| Commercial Clarity | 39.5 |
| Access Clarity | 39.5 |

## Agent readiness — 29.1 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Free · Open access — onboarding: open, pricing: free, trial: no (confidence: high).

## APIs (9)

- **AT Protocol Firehose (Event Stream)** — Public WebSocket event stream providing real-time access to all public activity on the AT Protocol network, including posts, likes, follows, and other repository events. No API ...
- **AT Protocol actor API** — Actor (user) profile, search, and preference operations
- **AT Protocol feed API** — Feed, post, timeline, and content operations
- **AT Protocol graph API** — Graph operations — follows, blocks, lists, and mutes
- **AT Protocol identity API** — DID and handle resolution, identity management
- **AT Protocol notification API** — Notification management
- **AT Protocol repo API** — Repository management, record CRUD operations
- **AT Protocol server API** — Server management, session creation, account administration
- **AT Protocol sync API** — Data synchronization, firehose, blob access

## Agentic access (1)

- **Atproto Agentic Access** — 37 operations · 11 acting

## Security (2)

- **Atproto Authentication** — http · 1 scheme
- **Atproto Domain Security** — TLSv1.3 · DMARC

## Plans (1)

- **Atproto Plans Pricing**

## Tags

Social Networking, Decentralized, Federated, Open-Source, Bluesky, Fediverse, Identity, XRPC, Lexicon

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/atproto/). Scores are computed from the provider's own public artifacts under a published rubric.