I’m using Discourse as my identity provider and it has been working great, you can use it to create a “Login” link on your website which will take your user to your Discourse instance and, if they’re already logged in or after completing the login flow, the user will be redirected to the return_sso_url you added to the payload, with the user credentials and info. This return_sso_url can be a route on your website that stores the authenticated session the way you prefer (like a session cookie) once it receives Discourse’s payload.