Micro-SaaS User Authentication

I know there are tons of cloud-based user authentication providers already, but the ones I've tried seem like an overkill for most Micro-SaaS developers. I really don't need customizable forms (I have already built my own), or the ability to scale up to millions of users, or the ability to import existing user databases. I simply need a set of REST APIs that allow me to:

1. create a new account (using SSL)
2. login (getting a new JWT in return)
3. update/change password with email confirmation
4. get email notifications when a new user signs up
5. manage users in a simple table format

It seems there is nothing like this available, which leads me to my question. How many other micro-SaaS folks could use something like this? Is there a market beyond myself?

The price would be cheap (maybe $5 per month for anything under 500 users).

I have built REST endpoints in the past for an employer that did exactly these sorts of things, and I generally understand authentication using JSON Web Tokens.

What are your thoughts? Is this a pain point for you?

Thanks!