Auth0 is identity-as-a-service infrastructure that's built to make implementing identity very easy for developers. It's a set of unified APIs and tools that instantly enables single sign on and user management for any of your applications or APIs. It works with apps or APIs running on any popular software stack, on any popular device, authenticating with any popular identity provider. An extensive list of identity providers, both enterprise (Active Directory, LDAP, etc) and social (Facebook, Google, Twitter, etc) is supported out of the box.
This offer is commercially available in multiple countries.