I set up Authentik for some of my services and it works.

The setup really threw me off but I powered through learning it. It’s a strange UI and process.

Basically you set it up with Nginx or Caddy or whatever reverse proxy you use. Your reverse proxy points to Authentik and Authentik takes that link and checks for authorization first. If not authorized, prompt login. If authorized, pass on to the subdomain or whatever it is.

To do all this, you’d need a domain.