# AT Protocol Lexicon Schemas

**Canonical:** https://apis.io/apis/at-protocol/lexicon/  
**Provider:** AT Protocol — https://apis.io/providers/at-protocol/  
**Base URL:** https://atproto.com/lexicons  
**Documentation:** https://atproto.com/guides/lexicon

AT Protocol Lexicon Schemas is one of 12 APIs that [AT Protocol](https://apis.io/providers/at-protocol/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include Lexicon, Schema, NSID, and Record Types. The published artifact set on APIs.io includes API documentation.

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 as both contract and code generation source for client libraries. Bluesky publishes the app.bsky.* and com.atproto.* lexicons that power the reference Bluesky application; third parties define their own NSIDs to ship independent applications on the same network.

## Machine-readable artifacts (3)

- **Documentation** — https://atproto.com/guides/lexicon
- **Specification** — https://atproto.com/specs/lexicon
- **Repository** — https://github.com/bluesky-social/atproto/tree/main/lexicons

## Other AT Protocol APIs (11)

- [AT Protocol XRPC API](https://apis.io/apis/at-protocol/atproto-xrpc/)
- [Personal Data Server (PDS) API](https://apis.io/apis/at-protocol/pds-api/)
- [AT Protocol Relay & Firehose](https://apis.io/apis/at-protocol/relay-firehose/)
- [Bluesky AppView API](https://apis.io/apis/at-protocol/bsky-appview/)
- [AT Protocol Identity (DID & Handles)](https://apis.io/apis/at-protocol/identity-did/)
- [AT Protocol Actor API](https://apis.io/apis/at-protocol/at-protocol-actor-api/)
- [AT Protocol Feed API](https://apis.io/apis/at-protocol/at-protocol-feed-api/)
- [AT Protocol Graph API](https://apis.io/apis/at-protocol/at-protocol-graph-api/)
- [AT Protocol Identity API](https://apis.io/apis/at-protocol/at-protocol-identity-api/)
- [AT Protocol Repo API](https://apis.io/apis/at-protocol/at-protocol-repo-api/)
- [AT Protocol Server API](https://apis.io/apis/at-protocol/at-protocol-server-api/)

## Tags

Lexicon, Schema, NSID, Record Types

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/at-protocol/lexicon/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/at-protocol/.