Group-Office has a built in Oauth 2.0 server for authentication. At the moment it’s mainly used to offer the OpenID connect 1.0 protocol.
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 Group-Office as an Authorization Server, as well as to obtain basic profile information about the End-User in an interoperable and REST-like manner.
You can add clients at System Settings -> OAuth 2.0.
We’ve used this to integrate:
But any system supporting OpenID connect should be able to use this feature.