Ask HN: What do you use to manage user authentication?

I've recently been working on a side project that I don't want to have to roll my own auth suite for. Firebase[0] and Netlify[1] both offer free authentication-as-a-service APIs. Does anyone have experience with one over the other? Are there other alternatives I'm not aware of?

[0]: https://firebase.google.com/docs/auth [1]: https://www.netlify.com/docs/identity/