Doorkeeper

Doorkeeper turns your Rails app into an OAuth 2 provider, so other applications can
authenticate against your accounts.

What you get

• Authorization code, client credentials and refresh token flows
• An application registration UI
• Scopes and token introspection
• PKCE support

Mounting it

# Gemfile
gem "doorkeeper"

rails generate doorkeeper:install
rails generate doorkeeper:migration

The installer adds use_doorkeeper to your routes, mounting under /oauth.

Which direction

Doorkeeper is for being the identity provider. If you want to consume other
providers' logins, that is OmniAuth's job.