About this option: API only

"Use API only" means you build ALL the login forms yourself.

This is what shop.markmoriarty.com/login does.

If you'd like to re-create this, auth flow fully hosted on your website with no redirects, follow this step.

If instead you want an OIDC experience (redirect the user to Log in with Link, just like you'd redirect the user to "Log in with Twitter), see the "OIDC / OAuth" option instead.