This is just a quick guide on how to authenticate your authentik users with Proton using SimpleLogin OIDC.
To accomplish this, first create a SimpleLogin acct by logging in with Proton. Once thats done go to https://app.simplelogin.io/developer and create a website. Give it your authentik URL.
Then go to Oauth Settings and copy your client ID and secret for next step. add your authentik URL in redirect URL like this https://auth.example.com/source/oauth/callback/simplelogin/ (simplelogin being slug of authentik)
In authentik go to Directory - Federation and Social login - Create and create an OpenID Oauth source
Name: SimpleLogin Slug: simplelogin User matching mode: i chose link with identical email Consumer key: Paste your key Consumer secret: Paste your secret authorization url: https://app.simplelogin.io/oauth2/authorize access token url: https://app.simplelogin.io/oauth2/token profile url: https://app.simplelogin.io/oauth2/userinfo OIDC Well-known URL: https://app.simplelogin.io/.well-known/openid-configuration
For logo, it appears authenik inverts your image, I dont know if its dark mode or bug but regardless here’s the regular and inverted image I used. Just right click and save image:
Now go to Flows and Stages - Flows - choose your default authentication stage - click it then click stage bindings - Click edit stage to the right of your identification stage - expand Source settings and make sure you CTL + click your newly created SimpleLogin source.
You should be able to logout and try to to login with your Proton account!