There's a big gap between "never build yourself" and "letting other people handle it". Yes, you should have full control over your auth, run it yourself and ke

There's a big gap between "never build yourself" and "letting other people handle it". Yes, you should have full control over your auth, run it yourself and keep the data - but you still should not build it yourself, you should use well-established solutions/libraries built by others instead of trying to figure out e.g. what's the proper way to salt passwords.