Firebase, is basically a back-end server in a box. Authentication, check, file storage , check. Databases, check. Firebase functions which allow for complex logic written in JavaScript, check. Hosting, check. Supabase comes really close, but has been much more difficult in actual use.

I'm working on a fully open source game right now, and I can't ethically tell people to hook into a closed source service. But I must admit, having to use supabase instead of firebase has made this much harder than it needs to be.