Caltech Shibboleth Identity Provider (InCommon)
Caltech operates its own Shibboleth identity provider at idp.caltech.edu, asserting scoped attributes for caltech.edu. The SAML 2.0 metadata is machine-readable and publicly retrievable both from the IdP itself and, signed, from the InCommon metadata query service — registrationAuthority https://incommon.org, and therefore reachable through eduGAIN. Advertises SAML 1.1, SAML 2.0 and the Shibboleth-native AuthnRequest binding, with HTTP-POST, HTTP-Redirect and POST-SimpleSign SSO bindings and a SOAP attribute authority. Verified live 2026-08-19 from both sources. This is the single most under-catalogued class of university API surface.