/.well-known/api-catalog (RFC 9727)

RFC 9727 defines `/.well-known/api-catalog` as the canonical machine entrypoint for discovering an organization's APIs, formatted as an RFC 9264 linkset. Presence of a catalog at this path is one of the cheapest, highest-impact agent-readiness signals — agents do not have to crawl HTML to find specs. As of 2026-05-22, a survey of 74 likely-candidate providers found only four serving a real RFC 9727 linkset at the well-known path — Cloudflare, Memesio, Merge.dev, and Zuplo — with example signal records committed for each.

API entry from apis.yml

apis.yml Raw ↑
aid: agent-readiness:well-known-api-catalog
name: /.well-known/api-catalog (RFC 9727)
tags:
- Discovery
- Linkset
- Agent Readiness
- Standards
humanURL: https://www.rfc-editor.org/rfc/rfc9727.html
baseURL: https://www.rfc-editor.org/rfc/rfc9727.html
properties:
- url: https://www.rfc-editor.org/rfc/rfc9727.html
  type: Documentation
- url: https://www.rfc-editor.org/rfc/rfc9264.html
  type: Documentation
- url: examples/agent-readiness-signal-cloudflare-well-known-catalog-example.json
  type: Example
- url: examples/agent-readiness-signal-memesio-well-known-catalog-example.json
  type: Example
- url: examples/agent-readiness-signal-merge-well-known-catalog-example.json
  type: Example
- url: examples/agent-readiness-signal-zuplo-well-known-catalog-example.json
  type: Example
description: RFC 9727 defines `/.well-known/api-catalog` as the canonical machine entrypoint for discovering
  an organization's APIs, formatted as an RFC 9264 linkset. Presence of a catalog at this path is one
  of the cheapest, highest-impact agent-readiness signals — agents do not have to crawl HTML to find specs.
  As of 2026-05-22, a survey of 74 likely-candidate providers found only four serving a real RFC 9727
  linkset at the well-known path — Cloudflare, Memesio, Merge.dev, and Zuplo — with example signal records
  committed for each.