Authorizer is an open-source authentication and authorization solution for your applications. Bring your database and have complete control over the user information. You can self-host authorizer instances and connect to any SQL database.
Easy to use and self-hostable. The key factor that sealed the deal for us was that it is built using golang and react which is our core stack and we could use it with our pre-existing MongoDB atlas instance.
I'm using Authorizer with Hasura and it's relatively easy to implement and it offers a nice set of features needed for authentication.
The only thing missing is I18n for email templates.