Add an OAuth provider

Google, Microsoft, and GitHub ship wired and config-gated. Adding another provider (or lighting up a shipped one) is a registration call plus a config block.

Light up a shipped provider

Set the credentials — the login button and the profile entry appear automatically once they're present:

"Auth": {
  "OAuth": {
    "Google": { "ClientId": "…", "ClientSecret": "…" }
  }
}

Keep the secret in environment variables or user-secrets. A provider with blank credentials is hidden, so you can ship all three and enable them per environment.

Add a new provider

Register it in the auth setup alongside the others (most providers have an AddXxx() ASP.NET extension or a generic OAuth handler), and add a matching Auth:OAuth:{Provider} config block. The login page reads the configured providers and renders a button for each — so the new one shows up with the same config-gated behaviour.

Signing in with a provider auto-provisions a confirmed account; users link and unlink providers from Profile → Connected accounts. See Authentication.