Ask HN: Open-source user management API that uses AWS?

I am looking to set up a user management system that would allow users to login/edit/ect from websites and apps.

Although I have found a few different options, I can not seem to find any service built on top of Amazon Web Services. My application runs on AWS so it would be nice to have the user registration be in the same place.

Does anyone know of such a service?

If not, is there a reason it does not exist?