Term Kind Topic What it is
Authorization Code Flow with PKCE PKCE protocol OAuth 2.0 & OIDC The OAuth flow recommended for all client types, in which an authorisation code is exchanged for tokens using a proof key that binds the exchange to the original requester.
Token Introspection protocol OAuth 2.0 & OIDC Asking the authorisation server whether a token is currently valid, rather than validating it locally from its signature.