🔌 Federation Endpoints
The HTTP APIs that federation entities expose
OpenID Federation defines 1 well-known discovery URL[1], 7 federation endpoints[2], and 1 registration endpoint[3]. Not every entity implements all of them — leaf entities only need the well-known URL, while Trust Anchors and Intermediates may implement up to eight. The registration endpoint is available to OpenID Providers, not TAs.
Real-World Analogy
Think of a government building with multiple service windows — each serves a specific purpose. The "Entity Configuration" window is at the front door (everyone has it). The "Fetch" and "List" windows are inside, only available to entities that manage subordinates.