What is OpenID Connect?
OpenID Connect 1.0 is a simple identity layer on top of the OAuth 2.0 protocol. It allows Clients to verify the identity of the End-User based on the authentication performed by an Authorization Server, as well as to obtain basic profile information about the End-User in an interoperable and REST-like manner.
OpenID 2.0 (Migration)
Google has deprecated OpenID 2.0 and will shut it down after a migration period. If your app uses OpenID 2.0, the userinfo endpoint, or OAuth 2.0 login (early version), you should migrate your app by the deadlines given in the migration timetable.
If you are looking for documentation for web applications that use the deprecated OpenID 2.0 for Google login, see OpenID 2.0 (Deprecated). For information about using the deprecated OpenID 2.0 authentication with Google Apps (hosted) accounts, see OpenID API for Google Apps accounts (Deprecated).
To get help on Stack Overflow with migrating your OpenID 2.0 app, tag your questions with 'google-openid'.
Question on Meta Stack Exchange:
|OpenID is Going Away Notice|