We have build a stand alone SaaS product, we're attracting Enterprise clients who want their users to log straight in. We are not looking for authorization, just simpler authentication; where the user gets an account without having to enter their name or email address.
We want to give our enterprise customers the ability to connect to our login system. Once we implement Oauth2, do we need to supply the end customers with an authentication server or is this something they sort themselves?
I have been looking at services, would https://github.com/fkooman/php-oauth be good?