I was lucky enough to come across Auth0 when building a site (ideacow.org) for my university’s student government that takes suggestions from students. Students can then vote and comment on other suggestions, allowing the most popular suggestions to come to the top. We use Flarum as our open source forum software.
Our university uses Shibboleth’s IdP software, which is difficult to implement particularly with web services that don’t allow much flexibility in terms of authentication. It was also an administrative pain to get them to allow us to authenticate against their IdP. However, now that we have integrated it with Auth0, we hope to allow other student groups to use Auth0 as their Identity Provider, which will make it much easier for student groups to use web services and restrict access to other students, or others in their group.
We are very grateful to Auth0 for their open-source plan. A paid plan would be financially infeasible for us, but we really don’t have many users. The OSS option allows us to make use of everything great about Auth0, and gives us the ability to invite other student groups to experiment and try the platform out in ways that were simply not possible before.