Auth0 for complex stuff is pretty outstanding in my experience! It's nice to get sane and reliable OAUTH as a service...

I've rolled a lot of different custom authentication solutions for small apps with a handful of users all the way up to millions of users and thousands of concurrent sessions... having an "out-of-box" service saves a TON of time and headache =)

Not affiliated with Auth0, just love it to all heck. The free-tier offering is very fully-featured - try it out!

Auth0 is nice tbh but I find it quite pricey once you scale a bit.

I think it’s important to make good decisions at the very start.

I am definitely not against auth0 and I think it’s great, just think well enough before using it because it might come free at the start but after you acquire more users it comes at a hefty price

+1 for Auth0. I've used it for my SaaS cause I was sure that if I bothered rolling out my own I'd definitely miss some critical point opening up my users to a breach. Not only that but depending on your market your users may expect social-media signups/logins which becomes a pain to implement and maintain. The Auth0 free-tier up to 7k active users was more than sufficient for me when bootstrapping a new project.