# Doorkeeper — awesome OAuth 2 provider for your Rails / Grape app.

[](https://rubygems.org/gems/doorkeeper)
[](https://github.com/doorkeeper-gem/doorkeeper/actions/workflows/ci.yml)
[](https://qlty.sh/gh/doorkeeper-gem/projects/doorkeeper)
[](https://coveralls.io/github/doorkeeper-gem/doorkeeper?branch=main)
[](https://dashboard.guardrails.io/gh/doorkeeper-gem/repos/21183)
[](https://dependabot.com)

Doorkeeper is a gem (Rails engine) that makes it easy to introduce OAuth 2 provider
functionality to your Ruby on Rails or Grape application.

Supported features:

- [The OAuth 2.0 Authorization Framework](https://datatracker.ietf.org/doc/html/rfc6749)
  - [Authorization Code Flow](https://datatracker.ietf.org/doc/html/rfc6749#section-4.1)
  - [Access Token Scopes](https://datatracker.ietf.org/doc/html/rfc6749#section-3.3)
  - [Refresh token](https://datatracker.ietf.org/doc/html/rfc6749#section-1.5)
  - [Implicit grant](https://datatracker.ietf.org/doc/html/rfc6749#section-4.2)
  - [Resource Owner Password Credentials](https://datatracker.ietf.org/doc/html/rfc6749#section-4.3)
  - [Client Credentials](https://datatracker.ietf.org/doc/html/rfc6749#section-4.4)
- [OAuth 2.0 Token Revocation](https://datatracker.ietf.org/doc/html/rfc7009)
- [OAuth 2.0 Token Introspection](https://datatracker.ietf.org/doc/html/rfc7662)
- [OAuth 2.0 Threat Model and Security Considerations](https://datatracker.ietf.org/doc/html/rfc6819)
- [OAuth 2.0 for Native Apps](https://datatracker.ietf.org/doc/html/rfc8252)
- [Proof Key for Code Exchange by OAuth Public Clients](https://datatracker.ietf.org/doc/html/rfc7636)
- [OAuth 2.0 Authorization Server Issuer Identification](https://datatracker.ietf.org/doc/html/rfc9207) — opt-in by setting `issuer`; adds the `iss` parameter to authorization redirects returned to the client
- [Resource Indicators for OAuth 2.0](https://datatracker.ietf.org/doc/html/rfc8707)

## Table of Contents





- [Documentation](#documentation)
- [Installation](#installation)
  - [Ruby on Rails](#ruby-on-rails)
  - [Grape](#grape)
- [ORMs](#orms)
- [Extensions](#extensions)
- [Database maintenance](#database-maintenance)
- [Resource Indicators](#resource-indicators)
- [Custom Grant Flows](#custom-grant-flows)
- [Custom Client Authentication Methods](#custom-client-authentication-methods)
- [Example Applications](#example-applications)
- [Sponsors](#sponsors)
- [Development](#development)
- [Contributing](#contributing)
- [Contributors](#contributors)
- [License](#license)



## Documentation

This documentation is valid for `main` branch. Please check the documentation for the version of doorkeeper you are using in:
https://github.com/doorkeeper-gem/doorkeeper/releases.

Additionally, other resources can be found on:

- [Guides](https://doorkeeper.gitbook.io/guides/) with how-to get started and configuration documentation
- See the [Wiki](https://github.com/doorkeeper-gem/doorkeeper/wiki) for articles on how to integrate with other solutions
- Screencast from [railscasts.com](http://railscasts.com/): [#353
OAuth with
Doorkeeper](http://railscasts.com/episodes/353-oauth-with-doorkeeper)
- See [upgrade guides](https://github.com/doorkeeper-gem/doorkeeper/wiki/Migration-from-old-versions)
- For general questions, please post on [Stack Overflow](http://stackoverflow.com/questions/tagged/doorkeeper)
- See [SECURITY.md](SECURITY.md) for this project's security disclose
  policy

## Installation

Installation depends on the framework you're using. The first step is to add the following to your Gemfile:

```ruby
gem 'doorkeeper'
```

And run `bundle install`. After this, check out the guide related to the framework you're using.

### Ruby on Rails

Doorkeeper currently supports Ruby on Rails >= 5.0. See the guide [here](https://doorkeeper.gitbook.io/guides/ruby-on-rails/getting-started).

### Grape

Guide for integration with Grape framework can be found [here](https://doorkeeper.gitbook.io/guides/grape/grape).

## ORMs

Doorkeeper supports Active Record by default, but can be configured to work with the following ORMs:

| ORM | Support via |
| :--- | :--- |
| Active Record | by default |
| MongoDB | [doorkeeper-gem/doorkeeper-mongodb](https://github.com/doorkeeper-gem/doorkeeper-mongodb) |
| Sequel | [nbulaj/doorkeeper-sequel](https://github.com/nbulaj/doorkeeper-sequel) |
| Couchbase | [acaprojects/doorkeeper-couchbase](https://github.com/acaprojects/doorkeeper-couchbase) |
| RethinkDB | [aca-labs/doorkeeper-rethinkdb](https://github.com/aca-labs/doorkeeper-rethinkdb) |

## Extensions

Extensions that are not included by default and can be installed separately.

|  | Link |
| :--- | :--- |
| OpenID Connect extension | [doorkeeper-gem/doorkeeper-openid\_connect](https://github.com/doorkeeper-gem/doorkeeper-openid_connect) |
| JWT Token support | [doorkeeper-gem/doorkeeper-jwt](https://github.com/doorkeeper-gem/doorkeeper-jwt) |
| Assertion grant extension | [doorkeeper-gem/doorkeeper-grants\_assertion](https://github.com/doorkeeper-gem/doorkeeper-grants_assertion) |
| I18n translations | [doorkeeper-gem/doorkeeper-i18n](https://github.com/doorkeeper-gem/doorkeeper-i18n) |
| CIBA - Client Initiated Backchannel Authentication Flow extension | [doorkeeper-ciba](https://github.com/autoseg/doorkeeper-ciba) |
| Device Authorization Grant | [doorkeeper-device_authorization_grant](https://github.com/exop-group/doorkeeper-device_authorization_grant) |

## Database maintenance

Doorkeeper does **not** automatically remove expired or revoked tokens and grants. The `oauth_access_tokens` and `oauth_access_grants` tables grow indefinitely and can reach millions of rows if left unmanaged.

Prune them periodically with the bundled rake task:

```bash
bundle exec rake doorkeeper:db:cleanup
```

This deletes expired and revoked access tokens and grants. See the [Rake tasks guide](https://doorkeeper.gitbook.io/guides/internals/rake) for details.

## Resource Indicators

Doorkeeper supports [Resource Indicators for OAuth 2.0 (RFC 8707)](https://datatracker.ietf.org/doc/html/rfc8707), allowing clients to signal which protected resource(s) they intend to access. Tokens are then audience-restricted to those resources.

### Setup

1. Run the generator to add the required `resource` column:

```bash
rails generate doorkeeper:resource_indicators
rails db:migrate
```

2. Configure a validator in your initializer:

```ruby
# config/initializers/doorkeeper.rb
Doorkeeper.configure do
  resource_indicator_validator ->(resource_indicators, client) {
    allowed = %w[https://api.example.com/ https://calendar.example.com/]
    resource_indicators.all? { |r| allowed.include?(r) }
  }
end
```

The callable receives an array of resource URIs and the OAuth client. Return `true` to accept or `false` to reject with `invalid_target`.

### Behavior

- Resource URIs must be absolute and must not contain a fragment component.
- Resource indicators are stored on grants and tokens.
- Token and refresh requests enforce subset restrictions against the original grant.
- Token introspection responses include `aud` when resource indicators are present.
- Grants issued with resource indicators retain their audience restriction even if the validator is later removed from configuration.

### Multiple resources

RFC 8707 uses repeated query parameters (`?resource=…&resource=…`) for multiple values, but Rack collapses repeated keys to the last value. Clients must use the Rails bracket syntax for multiple resource indicators:

```
?resource[]=https://api.example.com/&resource[]=https://calendar.example.com/
```

A single `resource=…` works as-is.

## Custom Grant Flows

Besides the built-in OAuth 2 flows, Doorkeeper can recognize and process any custom grant type through its grant flow registry — including grant types whose names are URNs or URIs, such as the SAML 2.0 bearer assertion grant defined by [RFC 7522](https://www.rfc-editor.org/rfc/rfc7522).

A grant flow bundles a matcher for the `grant_type` parameter with a strategy class that processes the token request. Register it before `Doorkeeper.configure` and enable it by adding its registered name to `grant_flows`:

```ruby
# config/initializers/doorkeeper.rb
Doorkeeper::GrantFlow.register(
  :saml2_bearer,
  grant_type_matches: "urn:ietf:params:oauth:grant-type:saml2-bearer",
  grant_type_strategy: SamlBearer::Strategy,
)

Doorkeeper.configure do
  grant_flows %w[authorization_code saml2_bearer]
  # ...
end
```

Note that `grant_flows` lists the *registered flow name* (`saml2_bearer`), while `grant_type_matches` — a `String` or a `Regexp` — is what the request's `grant_type` parameter is matched against.

The strategy class receives the authorization server as `server` and builds the request object handling the grant:

```ruby
module SamlBearer
  class Strategy < Doorkeeper::Request::Strategy
    delegate :client, :parameters, to: :server

    def request
      @request ||= TokenRequest.new(Doorkeeper.config, client, parameters)
    end
  end
end
```

The request object validates the grant and issues the token. Subclassing `Doorkeeper::OAuth::BaseRequest` provides the response handling, scope calculation and token creation, so only the grant-specific parts remain (per RFC 7522 §2.1 the `assertion` parameter carries a single SAML assertion, base64url-encoded without padding):

```
/* Detailed source-code truncated for AI context efficiency. */
```

The `client_supports_grant_flow` validation keeps the custom grant subject to the `allow_grant_flow_for_client` configuration option (per-client grant restrictions), just like the built-in flows.

Flows can also handle custom `response_type` values on the authorization endpoint via the `response_type_matches` / `response_type_strategy` options — see the built-in registrations in [`lib/doorkeeper/grant_flow.rb`](lib/doorkeeper/grant_flow.rb) for reference. An extension can also group several flows under one configuration name with `Doorkeeper::GrantFlow.register_alias` (e.g. the OpenID Connect extension registers `implicit_oidc` to expand to multiple response types).

## Custom Client Authentication Methods

Doorkeeper authenticates clients (RFC 6749 §2.3) through a registry of named methods. `client_secret_basic`, `client_secret_post` and `none` are built in, and an application or extension can register additional ones — for instance to keep accepting credentials that a partner integration sends in its own headers.

A method is any object that responds to `matches_request?` and `authenticate`. Register it before `Doorkeeper.configure` and enable it by listing its registered name in `client_authentication`:

```ruby
# config/initializers/doorkeeper.rb
Doorkeeper::ClientAuthentication.register(
  :partner_headers,
  PartnerHeaders::Authentication,
)

Doorkeeper.configure do
  client_authentication %i[client_secret_basic client_secret_post partner_headers none]
  # ...
end
```

The order of `client_authentication` is the order the methods are tried in: the first one whose `matches_request?` returns true handles the request.

`matches_request?` decides whether the request carries this method's credentials, and `authenticate` extracts them into a `Doorkeeper::ClientAuthentication::Credentials` pair (or `nil`):

```ruby
module PartnerHeaders
  class Authentication
    def self.matches_request?(request)
      request.get_header("HTTP_X_CLIENT_ID").present? &&
        request.get_header("HTTP_X_CLIENT_SECRET").present?
    end

    def self.authenticate(request)
      Doorkeeper::ClientAuthentication::Credentials.new(
        request.get_header("HTTP_X_CLIENT_ID"),
        request.get_header("HTTP_X_CLIENT_SECRET"),
      )
    end
  end
end
```

Two things are worth keeping in mind when writing one.

**Keep `matches_request?` as narrow as possible.** RFC 6749 §2.3 forbids a client from using more than one authentication method in a single request, and Doorkeeper enforces that across the whole registry rather than only the enabled methods. A method that matches too broadly therefore collides with a built-in one and the request is answered with `invalid_request`.

**The returned credentials are resolved with `by_uid_and_secret`.** A blank secret resolves only a public (non-confidential) client — that is what the built-in `none` method relies on — while a confidential client is resolved only when the secret matches the registered one. A method that establishes the client's identity by some other proof, such as a client certificate or a signed assertion, therefore still has to produce the registered secret for a confidential client.

Enabled methods are advertised in the authorization server metadata, so a registered method appears in `token_endpoint_auth_methods_supported` at `/.well-known/oauth-authorization-server` once `client_authentication` lists it.

## Example Applications

These applications show how Doorkeeper works and how to integrate with it. Start with the oAuth2 server and use the clients to connect with the server.

| Application | Link |
| :--- | :--- |
| OAuth2 Server with Doorkeeper | [doorkeeper-gem/doorkeeper-provider-app](https://github.com/doorkeeper-gem/doorkeeper-provider-app) |
| Sinatra Client connected to Provider App | [doorkeeper-gem/doorkeeper-sinatra-client](https://github.com/doorkeeper-gem/doorkeeper-sinatra-client) |
| Devise + Omniauth Client | [doorkeeper-gem/doorkeeper-devise-client](https://github.com/doorkeeper-gem/doorkeeper-devise-client) |

You may want to create a client application to
test the integration. Check out these [client
examples](https://github.com/doorkeeper-gem/doorkeeper/wiki/Example-Applications)
in our wiki or follow this [tutorial
here](https://github.com/doorkeeper-gem/doorkeeper/wiki/Testing-your-provider-with-OAuth2-gem).

## Sponsors

[](#backers) 
[](#sponsors)

Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [[Become a sponsor](https://opencollective.com/doorkeeper-gem#sponsor)]

[](https://codecademy.com/about/careers?utm_source=doorkeeper-gem)

> Codecademy supports open source as part of its mission to democratize tech. Come help us build the education the world deserves: [https://codecademy.com/about/careers](https://codecademy.com/about/careers?utm_source=doorkeeper-gem)



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## Development

To run the local engine server:

```
bundle install
bundle exec rake doorkeeper:server
````

By default, it uses the latest Rails version with ActiveRecord. To run the
tests with a specific Rails version:

```
BUNDLE_GEMFILE=gemfiles/rails_6_0.gemfile bundle exec rake
```

You can also experiment with the changes using `bin/console`. It uses in-memory SQLite database and default
Doorkeeper config, but you can reestablish connection or reconfigure the gem if you need.

## Contributing

Want to contribute and don't know where to start? Check out [features we're
missing](https://github.com/doorkeeper-gem/doorkeeper/wiki/Supported-Features),
create [example
apps](https://github.com/doorkeeper-gem/doorkeeper/wiki/Example-Applications),
integrate the gem with your app and let us know!

Also, check out our [contributing guidelines page](CONTRIBUTING.md).

## Contributors

Thanks to all our [awesome
contributors](https://github.com/doorkeeper-gem/doorkeeper/graphs/contributors)!

[](https://github.com/doorkeeper-gem/doorkeeper/graphs/contributors)

## License

MIT License. Created in Applicake. Maintained by the community.