My team and I are currrently developing a mobile app with 2 frontends : Android, and HTML/CSS and a REST API backend in PHP. We want to implement a global authentication, by global I mean usable on both platforms and can allow authenticating with any king of email adresses. We tried GoogleToolkit for Android and Google Client for PHP, but we can't get user info from the gmail adresses in the first case, and we can't authenticate with other emails in the web version. I read articles about OpenID, but it seems to be deprecated. We are definitely lost.
So basically, what we need is an authentication system that uses any email address and provides at least the Name of this user.
Thank you!