Authorizing OAuth apps

GitHub Enterprise Server's OAuth implementation supports the standard authorization code grant type and the OAuth 2.0 Device Authorization Grant for apps that don't have access to a web browser.

If you want to skip authorizing your app in the standard way, such as when testing your app, you can use the non-web application flow.

To authorize your OAuth app, consider which authorization flow best fits your app.

• web application flow: Used to authorize users for standard OAuth apps that run in the browser. (The implicit grant type is not supported.)
• device flow: Used for headless apps, such as CLI tools.

Web application flow

The web application flow to authorize users for your app is:

1. Users are redirected to request their GitHub identity
2. Users are redirected back to your site by GitHub
3. Your app accesses the API with the user's access token

1. Request a user's GitHub identity

GET http(s)://HOSTNAME/login/oauth/authorize

This endpoint takes the following input parameters.

Query parameter	Type	Required?	Description
client_id	string	Required	The client ID you received from GitHub when you registered.
redirect_uri	string	Strongly recommended	The URL in your application where users will be sent after authorization. See details below about redirect urls.
login	string	Optional	Suggests a specific account to use for signing in and authorizing the app.
scope	string	Context dependent	A space-delimited list of scopes. If not provided, scope defaults to an empty list for users that have not authorized any scopes for the application. For users who have authorized scopes for the application, the user won't be shown the OAuth authorization page with the list of scopes. Instead, this step of the flow will automatically complete with the set of scopes the user has authorized for the application. For example, if a user has already performed the web flow twice and has authorized one token with user scope and another token with repo scope, a third web flow that does not provide a scope will receive a token with user and repo scope.
state	string	Strongly recommended	An unguessable random string. It is used to protect against cross-site request forgery attacks.
allow_signup	string	Optional	Whether or not unauthenticated users will be offered an option to sign up for GitHub during the OAuth flow. The default is true. Use false when a policy prohibits signups.

The PKCE (Proof Key for Code Exchange) parameters code_challenge and code_challenge_method are not supported at this time. CORS pre-flight requests (OPTIONS) are not supported at this time.

2. Users are redirected back to your site by GitHub

If the user accepts your request, GitHub Enterprise Server redirects back to your site with a temporary code in a code parameter as well as the state you provided in the previous step in a state parameter. The temporary code will expire after 10 minutes. If the states don't match, then a third party created the request, and you should abort the process.

Exchange this code for an access token:

POST http(s)://HOSTNAME/login/oauth/access_token

This endpoint takes the following input parameters.

Parameter name	Type	Required?	Description
client_id	string	Required	The client ID you received from GitHub Enterprise Server for your OAuth app.
client_secret	string	Required	The client secret you received from GitHub Enterprise Server for your OAuth app.
code	string	Required	The code you received as a response to Step 1.
redirect_uri	string	Strongly recommended	The URL in your application where users are sent after authorization. We can use this to match against the URI originally provided when the code was issued, to prevent attacks against your service.

By default, the response takes the following form:

access_token=gho_16C7e42F292c6912E7710c838347Ae178B4a&scope=repo%2Cgist&token_type=bearer

You can also receive the response in different formats if you provide the format in the Accept header. For example, Accept: application/json or Accept: application/xml:

Accept: application/json
{
  "access_token":"gho_16C7e42F292c6912E7710c838347Ae178B4a",
  "scope":"repo,gist",
  "token_type":"bearer"
}

Accept: application/xml
<OAuth>
  <token_type>bearer</token_type>
  <scope>repo,gist</scope>
  <access_token>gho_16C7e42F292c6912E7710c838347Ae178B4a</access_token>
</OAuth>

3. Use the access token to access the API

The access token allows you to make requests to the API on a behalf of a user.

Authorization: Bearer OAUTH-TOKEN
GET http(s)://HOSTNAME/api/v3/user

For example, in curl you can set the Authorization header like this:

curl -H "Authorization: Bearer OAUTH-TOKEN" http(s)://HOSTNAME/api/v3/user

Every time you receive an access token, you should use the token to revalidate the user's identity. A user can change which account they are signed into when you send them to authorize your app, and you risk mixing user data if you do not validate the user's identity after every sign in.

Device flow

The device flow allows you to authorize users for a headless application, such as a CLI tool or the Git Credential Manager.

Before you can use the device flow to authorize and identify users, you must first enable it in your app's settings. For more information about enabling the device flow in your app, see Modifying a GitHub App registration for GitHub Apps and Modifying an OAuth app for OAuth apps.

Overview of the device flow

1. Your app requests device and user verification codes and gets the authorization URL where the user will enter the user verification code.
2. The app prompts the user to enter a user verification code at http(s)://HOSTNAME/login/device.
3. The app polls for the user authentication status. Once the user has authorized the device, the app will be able to make API calls with a new access token.

Step 1: App requests the device and user verification codes from GitHub

POST http(s)://HOSTNAME/login/device/code

Your app must request a user verification code and verification URL that the app will use to prompt the user to authenticate in the next step. This request also returns a device verification code that the app must use to receive an access token and check the status of user authentication.

The endpoint takes the following input parameters.

Parameter name	Type	Description
client_id	string	Required. The client ID you received from GitHub Enterprise Server for your app.
scope	string	A space-delimited list of the scopes that your app is requesting access to. For more information, see Scopes for OAuth apps.

By default, the response takes the following form:

device_code=3584d83530557fdd1f46af8289938c8ef79f9dc5&expires_in=900&interval=5&user_code=WDJB-MJHT&verification_uri=https%3A%2F%2FHOSTNAME%2Flogin%2Fdevice

Parameter name	Type	Description
device_code	string	The device verification code is 40 characters and used to verify the device.
user_code	string	The user verification code is displayed on the device so the user can enter the code in a browser. This code is 8 characters with a hyphen in the middle.
verification_uri	string	The verification URL where users need to enter the user_code: http(s)://HOSTNAME/login/device.
expires_in	integer	The number of seconds before the device_code and user_code expire. The default is 900 seconds or 15 minutes.
interval	integer	The minimum number of seconds that must pass before you can make a new access token request (POST http(s)://HOSTNAME/login/oauth/access_token) to complete the device authorization. For example, if the interval is 5, then you cannot make a new request until 5 seconds pass. If you make more than one request over 5 seconds, then you will hit the rate limit and receive a slow_down error.

You can also receive the response in different formats if you provide the format in the Accept header. For example, Accept: application/json or Accept: application/xml:

Accept: application/json
{
  "device_code": "3584d83530557fdd1f46af8289938c8ef79f9dc5",
  "user_code": "WDJB-MJHT",
  "verification_uri": "http(s)://HOSTNAME/login/device",
  "expires_in": 900,
  "interval": 5
}

Accept: application/xml
<OAuth>
  <device_code>3584d83530557fdd1f46af8289938c8ef79f9dc5</device_code>
  <user_code>WDJB-MJHT</user_code>
  <verification_uri>http(s)://HOSTNAME/login/device</verification_uri>
  <expires_in>900</expires_in>
  <interval>5</interval>
</OAuth>

Step 2: Prompt the user to enter the user code in a browser

Your device will show the user verification code and prompt the user to enter the code at http(s)://HOSTNAME/login/device.

Step 3: App polls GitHub to check if the user authorized the device

POST http(s)://HOSTNAME/login/oauth/access_token

Your app will make device authorization requests that poll POST http(s)://HOSTNAME/login/oauth/access_token, until the device and user codes expire or the user has successfully authorized the app with a valid user code. The app must use the minimum polling interval retrieved in step 1 to avoid rate limit errors. For more information, see Rate limits for the device flow.

The user must enter a valid code within 15 minutes (or 900 seconds). After 15 minutes, you will need to request a new device authorization code with POST http(s)://HOSTNAME/login/device/code.

Once the user has authorized, the app will receive an access token that can be used to make requests to the API on behalf of a user.

The endpoint takes the following input parameters.

Parameter name	Type	Description
client_id	string	Required. The client ID you received from GitHub Enterprise Server for your OAuth app.
device_code	string	Required. The device_code you received from the POST http(s)://HOSTNAME/login/device/code request.
grant_type	string	Required. The grant type must be urn:ietf:params:oauth:grant-type:device_code.

By default, the response takes the following form:

access_token=gho_16C7e42F292c6912E7710c838347Ae178B4a&token_type=bearer&scope=repo%2Cgist

You can also receive the response in different formats if you provide the format in the Accept header. For example, Accept: application/json or Accept: application/xml:

Accept: application/json
{
 "access_token": "gho_16C7e42F292c6912E7710c838347Ae178B4a",
  "token_type": "bearer",
  "scope": "repo,gist"
}

Accept: application/xml
<OAuth>
  <access_token>gho_16C7e42F292c6912E7710c838347Ae178B4a</access_token>
  <token_type>bearer</token_type>
  <scope>gist,repo</scope>
</OAuth>

Rate limits for the device flow

When a user submits the verification code on the browser, there is a rate limit of 50 submissions in an hour per application.

If you make more than one access token request (POST http(s)://HOSTNAME/login/oauth/access_token) within the required minimum timeframe between requests (or interval), you'll hit the rate limit and receive a slow_down error response. The slow_down error response adds 5 seconds to the last interval. For more information, see the Error codes for the device flow.

Error codes for the device flow

Error code	Description
authorization_pending	This error occurs when the authorization request is pending and the user hasn't entered the user code yet. The app is expected to keep polling the POST http(s)://HOSTNAME/login/oauth/access_token request without exceeding the interval, which requires a minimum number of seconds between each request.
slow_down	When you receive the slow_down error, 5 extra seconds are added to the minimum interval or timeframe required between your requests using POST http(s)://HOSTNAME/login/oauth/access_token. For example, if the starting interval required at least 5 seconds between requests and you get a slow_down error response, you must now wait a minimum of 10 seconds before making a new request for an OAuth access token. The error response includes the new interval that you must use.
expired_token	If the device code expired, then you will see the token_expired error. You must make a new request for a device code.
unsupported_grant_type	The grant type must be urn:ietf:params:oauth:grant-type:device_code and included as an input parameter when you poll the OAuth token request POST http(s)://HOSTNAME/login/oauth/access_token.
incorrect_client_credentials	For the device flow, you must pass your app's client ID, which you can find on your app settings page. The client_secret is not needed for the device flow.
incorrect_device_code	The device_code provided is not valid.
access_denied	When a user clicks cancel during the authorization process, you'll receive a access_denied error and the user won't be able to use the verification code again.
device_flow_disabled	Device flow has not been enabled in the app's settings. For more information, see Device flow.

For more information, see the OAuth 2.0 Device Authorization Grant.

Non-Web application flow

Non-web authentication is available for limited situations like testing. If you need to, you can use Basic Authentication to create a personal access token using your personal access tokens settings page. This technique enables the user to revoke access at any time.

Redirect URLs

The redirect_uri parameter is optional. If left out, GitHub will redirect users to the callback URL configured in the OAuth app settings. If provided, the redirect URL's host (excluding sub-domains) and port must exactly match the callback URL. The redirect URL's path must reference a subdirectory of the callback URL.

CALLBACK: http://example.com/path

GOOD: http://example.com/path
GOOD: http://example.com/path/subdir/other
GOOD: http://oauth.example.com/path
GOOD: http://oauth.example.com/path/subdir/other
BAD:  http://example.com/bar
BAD:  http://example.com/
BAD:  http://example.com:8080/path
BAD:  http://oauth.example.com:8080/path
BAD:  http://example.org

Loopback redirect urls

The optional redirect_uri parameter can also be used for loopback URLs, which is useful for native applications running on a desktop computer. If the application specifies a loopback URL and a port, then after authorizing the application users will be redirected to the provided URL and port. The redirect_uri does not need to match the port specified in the callback URL for the app.

For the http://127.0.0.1/path callback URL, you can use this redirect_uri if your application is listening on port 1234:

http://127.0.0.1:1234/path

Note that OAuth RFC recommends not to use localhost, but instead to use loopback literal 127.0.0.1 or IPv6 ::1.

Creating multiple tokens for OAuth apps

You can create multiple tokens for a user/application/scope combination to create tokens for specific use cases.

This is useful if your OAuth app supports one workflow that uses GitHub for sign-in and only requires basic user information. Another workflow may require access to a user's private repositories. Using multiple tokens, your OAuth app can perform the web flow for each use case, requesting only the scopes needed. If a user only uses your application to sign in, they are never required to grant your OAuth app access to their private repositories.

There is a limit of ten tokens that are issued per user/application/scope combination, and a rate limit of ten tokens created per hour. If an application creates more than ten tokens for the same user and the same scopes, the oldest tokens with the same user/application/scope combination are revoked. However, hitting the hourly rate limit will not revoke your oldest token. Instead, it will trigger a re-authorization prompt within the browser, asking the user to double check the permissions they're granting your app. This prompt is intended to give a break to any potential infinite loop the app is stuck in, since there's little to no reason for an app to request ten tokens from the user within an hour.

Directing users to review their access

You can link to authorization information for an OAuth app so that users can review and revoke their application authorizations.

To build this link, you'll need your OAuth app's client_id that you received from GitHub when you registered the application.

http(s)://HOSTNAME/settings/connections/applications/:client_id

Troubleshooting

• Troubleshooting authorization request errors
• Troubleshooting OAuth app access token request errors
• Device flow errors
• Token expiration and revocation

Further reading

• About authentication to GitHub