OpenID Connect is a simple identity layer that allows clients like mobile or web apps to verify user identities based on an authentication performed by an authorization server, as well as obtain basic profile information about users. It is built on OAuth 2.0 and defined by the OpenID Foundation. The specification defines core features as well as optional discovery, dynamic registration, session management, and OAuth 2.0 response types. Major companies like Google, Salesforce, and Microsoft have implemented or are deploying OpenID Connect to provide single sign-on for web and mobile clients.