What is the difference between SAML, OAuth, and OpenID Connect?

Security Assertion Markup Language, or SAML, is an XML-based framework for exchanging authentication and authorization data between an identity provider and a service provider, primarily used for enterprise single sign-on. OAuth 2.0 is an authorization framework that grants third-party applications limited access to user resources without sharing passwords, using access tokens. OpenID Connect, or OIDC, is an identity layer built on top of OAuth 2.0 that adds authentication, providing user identity information through ID tokens.