---
type: Glossary Term
title: "API Catalog (RFC 9727)"
description: "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)."
resource: "https://agenticweb.wiki/terms/api-catalog/"
tags: ["glossary", "discover"]
status: stable
generated: { by: agenticweb-builder/1.0, at: 2026-10-23T00:00:00Z }
verified: { by: process:agenticweb-engine, at: 2026-10-23T00:00:00Z }
stale_after: 2026-11-22T00:00:00Z
sources:
  - id: ref-1
    resource: "https://www.rfc-editor.org/rfc/rfc9727.html"
    last_modified: 2025-06-01T00:00:00Z
---

# API Catalog (RFC 9727)

**`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.

# Knowledge Graph

* **Related standards**: [api-catalog: A Well-Known URI and Link Relation to Help Discovery of APIs](/okf/protocols/api-catalog-rfc9727.md), [Agentic Resource Discovery](/okf/protocols/ard.md)

[^ref-1]: https://www.rfc-editor.org/rfc/rfc9727.html (https://www.rfc-editor.org/rfc/rfc9727.html)