documentation/content/en/spec/oauth.md

title	description	menu
OAuth	An open standard for token-based authentication and authorization on the Internet	docs weight parent 50 spec

What is OAuth?

The Mastodon API has many methods that require authentication from a client or authorization from a user. This is accomplished with OAuth 2.0, an authorization framework described in RFC 6749 that allows third-party applications to obtain limited access to an HTTP service on behalf of a resource owner, through the use of a standardized authorization flow that generates a client access token to be used with HTTP requests.

Mastodon supports the following OAuth 2 flows:

• Authorization code flow: For end-users
• Password grant flow: For bots and other single-user applications
• Client credentials flow: For applications that do not act on behalf of users

To obtain an OAuth token for a Mastodon website, make sure that you allow your users to specify the domain they want to connect to before login. Use that domain to [acquire a client id/secret]({{< relref "../methods/apps/#create-an-application" >}}) and then [proceed with normal OAuth 2]({{< relref "../methods/apps/oauth.md" >}}).

OAuth 2 endpoints implemented

The following descriptions are taken from the Doorkeeper documentation. Mastodon uses Doorkeeper to implement OAuth 2. For more information on how to use these endpoints, see the [API documentation for OAuth.]({{< relref "../methods/apps/oauth.md" >}})

{{< caption-link url="https://github.com/tootsuite/mastodon/blob/master/config/initializers/doorkeeper.rb" caption="Doorkeeper config initializer" >}}

[GET /oauth/authorize]({{< relref "../methods/apps/oauth.md#authorize-a-user" >}})

Displays an authorization form to the user. If approved, it will create and return an authorization code, then redirect to the desired redirect_uri, or show the authorization code if urn:ietf:wg:oauth:2.0:oob was requested.

[POST /oauth/token]({{< relref "../methods/apps/oauth.md#obtain-a-token" >}})

Obtain an access token. This corresponds to the token endpoint, section 3.2 of the OAuth 2 RFC.

[POST /oauth/revoke]({{< relref "../methods/apps/oauth.md#revoke-token" >}})

Post here with client credentials to revoke an access token. This corresponds to the token endpoint, using the OAuth 2.0 Token Revocation RFC RFC 7009.

Common gotchas

• When registering an application using Mastodon's REST API, there is a scopes parameter. When interfacing with OAuth endpoints, you must use the scope parameter instead, and this parameter's value must be a subset of the scopes registered with the app. You cannot include anything that wasn't in the original set.
• When registering an application using Mastodon's REST API, there is a redirect_uris parameter. When interfacing with OAuth endpoints, you must use the redirect_uri parameter instead, and this parameter's value must be one of the redirect_uris registered with the app.