I’ve used auth0, and the documentation was OK, but hard to find what I was looking for. i.e. the JS boilerplate for logging in using the Lock. I ended up finding that in a random code sample. Contrast that with Firebase, which has clear step-by-step tutorials, and offers the complete configuration object and initialization code in the console.
But the deal breaker with auth0 is that yesterday I was unable to log in and password reset didn’t send any emails, so I was effectively locked out of my account. I posted on their community forum but there’s been no reply.
I still don’t understand how my password or email was changed without receiving any confirmation email. As I mentioned in that post, I’m not a security noob, neither a target of any sort, I used a strong password, so the likelihood of being hacked is infinitesimal. And again, when your password or email are changed, any serious service will send a notification to the (old) email address. I have received none.