[citation needed] OpenID Connect (OIDC) is an identity layer on top of OAuth.
In the domain model associated with OIDC, an identity provider is a special type of OAuth 2.0 authorization server.
Specifically, a system entity called an OpenID Provider issues JSON-formatted identity tokens to OIDC relying parties via a RESTful HTTP API.
In the SAML domain model, an identity provider is a special type of authentication authority.
A relying party that consumes these authentication assertions is called a SAML service provider.