# Providers

Providers allow external applications to authenticate against passbook and use its user information.

## OpenID Provider

This provider utilises the commonly used OpenID Connect variation of OAuth2.

## OAuth2 Provider

This provider is slightly different than the OpenID Provider. While it uses the same basic OAuth2 Protocol, it provides a GitHub-compatible endpoint. This allows you to integrate applications which don't support custom OpenID providers.
The API exposes username, email, name, and groups in a GitHub-compatible format.
This provider currently supports the following scopes:

- `openid`: Access OpenID Userinfo
- `userinfo`: Access OpenID Userinfo
- `email`: Access OpenID Email
- `user:email`: GitHub Compatibility: User Email
- `read:org`: GitHub Compatibility: User Groups

## SAML Provider

This provider allows you to integrate enterprise software using the SAML2 Protocol. It supports signed requests and uses [Property Mappings](property-mappings/index.md#saml-property-mapping) to determine which fields are exposed and what values they return. This makes it possible to expose vendor-specific fields.
Default fields are exposed through auto-generated Property Mappings, which are prefixed with "Autogenerated".