# API Catalog (RFC 9727)

[1 · Discover](/category/discover/)

| API Catalog (RFC 9727) |
| --- |
| Category | [Discover](/category/discover/) |
| Also known as | RFC 9727, /.well-known/api-catalog, linkset |
| Related | [api-catalog: A Well-Known URI and Link Relation to Help Discovery of APIs](/protocols/api-catalog-rfc9727/), [Agentic Resource Discovery](/protocols/ard/) |

[Discover](/category/discover/) api-catalog (RFC 9727, published June 2025) is an IANA-registered well-known URI (/.well-known/api-catalog) and HTTP link relation (rel="api-catalog") that returns an RFC 9264 application/linkset+json document listing a publisher's machine-readable APIs, OpenAPI specifications (service-desc), documentation (service-doc), and status endpoints (status). In the agentic web, RFC 9727 provides the standards-track IETF foundation for domain-level API discovery alongside /.well-known/ard.json. Used by: api-catalog-rfc9727, ard.

## Instances

Not applicable.

## See also

- [api-catalog: A Well-Known URI and Link Relation to Help Discovery of APIs](/protocols/api-catalog-rfc9727/)
- [Agentic Resource Discovery](/protocols/ard/)

## References

- [https://www.rfc-editor.org/rfc/rfc9727.html](https://www.rfc-editor.org/rfc/rfc9727.html) (2025-06) VERIFIED

[JSON](/terms/api-catalog/index.json) · [Markdown](/terms/api-catalog/index.md) · [OKF v0.2](/okf/terms/api-catalog.md)