Drupal is a free, open source content management system, primarily aimed at websites but equally capable of providing content to frameworks like React, apps, services like Alexa, whatever you can think of.
I knew I wanted to allow "social" login on this website as it made me happier that the usernames I might see appearing are more likely to be the people I assume they are — they will have some sort of "background check" by virtue of their activity on those other social sites, whatever they were. Well, thanks to drupal/openid_connect, I have successfully implemented login via GitHub, LinkedIn, and Google.