gitlab-org--gitlab-foss/doc/api

GitLab API

Automate GitLab via a simple and powerful API. All definitions can be found under /lib/api.

Resources

Documentation for various API resources can be found separately in the following locations:

• Branches
• Builds
• Build triggers
• Build Variables
• Commits
• Deploy Keys
• Groups
• Issues
• Keys
• Labels
• Merge Requests
• Milestones
• Open source license templates
• Namespaces
• Notes (comments)
• Projects including setting Webhooks
• Project Snippets
• Repositories
• Repository Files
• Runners
• Services
• Session
• Settings
• System Hooks
• Tags
• Users

Internal CI API

The following documentation is for the internal CI API:

• Builds
• Runners

Authentication

All API requests require authentication. You need to pass a private_token parameter via query string or header. If passed as a header, the header name must be PRIVATE-TOKEN (uppercase and with a dash instead of an underscore). You can find or reset your private token in your account page (/profile/account).

If private_token is invalid or omitted, then an error message will be returned with status code 401:

{
  "message": "401 Unauthorized"
}

API requests should be prefixed with api and the API version. The API version is defined in lib/api.rb.

Example of a valid API request:

GET https://gitlab.example.com/api/v3/projects?private_token=9koXpg98eAheJpvBs5tK

Example of a valid API request using cURL and authentication via header:

curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects"

The API uses JSON to serialize data. You don't need to specify .json at the end of an API URL.

Authentication with OAuth2 token

Instead of the private_token you can transmit the OAuth2 access token as a header or as a parameter.

Example of OAuth2 token as a parameter:

curl https://gitlab.example.com/api/v3/user?access_token=OAUTH-TOKEN

Example of OAuth2 token as a header:

curl -H "Authorization: Bearer OAUTH-TOKEN" https://example.com/api/v3/user

Read more about GitLab as an OAuth2 client.

Status codes

The API is designed to return different status codes according to context and action. This way, if a request results in an error, the caller is able to get insight into what went wrong.

The following table gives an overview of how the API functions generally behave.

Request type	Description
GET	Access one or more resources and return the result as JSON.
POST	Return 201 Created if the resource is successfully created and return the newly created resource as JSON.
GET / PUT / DELETE	Return 200 OK if the resource is accessed, modified or deleted successfully. The (modified) result is returned as JSON.
DELETE	Designed to be idempotent, meaning a request to a resource still returns 200 OK even it was deleted before or is not available. The reasoning behind this, is that the user is not really interested if the resource existed before or not.

The following table shows the possible return codes for API requests.

Return values	Description
200 OK	The GET, PUT or DELETE request was successful, the resource(s) itself is returned as JSON.
201 Created	The POST request was successful and the resource is returned as JSON.
304 Not Modified	Indicates that the resource has not been modified since the last request.
400 Bad Request	A required attribute of the API request is missing, e.g., the title of an issue is not given.
401 Unauthorized	The user is not authenticated, a valid user token is necessary.
403 Forbidden	The request is not allowed, e.g., the user is not allowed to delete a project.
404 Not Found	A resource could not be accessed, e.g., an ID for a resource could not be found.
405 Method Not Allowed	The request is not supported.
409 Conflict	A conflicting resource already exists, e.g., creating a project with a name that already exists.
422 Unprocessable	The entity could not be processed.
500 Server Error	While handling the request something went wrong server-side.

Sudo

All API requests support performing an API call as if you were another user, provided your private token is from an administrator account. You need to pass the sudo parameter either via query string or a header with an ID/username of the user you want to perform the operation as. If passed as a header, the header name must be SUDO (uppercase).

If a non administrative private_token is provided, then an error message will be returned with status code 403:

{
  "message": "403 Forbidden: Must be admin to use sudo"
}

If the sudo user ID or username cannot be found, an error message will be returned with status code 404:

{
  "message": "404 Not Found: No user id or username for: <id/username>"
}

---

Example of a valid API call and a request using cURL with sudo request, providing a username:

GET /projects?private_token=9koXpg98eAheJpvBs5tK&sudo=username

curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --header "SUDO: username" "https://gitlab.example.com/api/v3/projects"

Example of a valid API call and a request using cURL with sudo request, providing an ID:

GET /projects?private_token=9koXpg98eAheJpvBs5tK&sudo=23

curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --header "SUDO: 23" "https://gitlab.example.com/api/v3/projects"

Pagination

Sometimes the returned result will span across many pages. When listing resources you can pass the following parameters:

Parameter	Description
page	Page number (default: 1)
per_page	Number of items to list per page (default: 20, max: 100)

In the example below, we list 50 namespaces per page.

curl -X PUT -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/namespaces?per_page=50

Pagination Link header

Link headers are sent back with each response. They have rel set to prev/next/first/last and contain the relevant URL. Please use these links instead of generating your own URLs.

In the cURL example below, we limit the output to 3 items per page (per_page=3) and we request the second page (page=2) of comments of the issue with ID 8 which belongs to the project with ID 8:

curl -I -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/8/issues/8/notes?per_page=3&page=2

The response will then be:

HTTP/1.1 200 OK
Cache-Control: no-cache
Content-Length: 1103
Content-Type: application/json
Date: Mon, 18 Jan 2016 09:43:18 GMT
Link: <https://gitlab.example.com/api/v3/projects/8/issues/8/notes?page=1&per_page=3>; rel="prev", <https://gitlab.example.com/api/v3/projects/8/issues/8/notes?page=3&per_page=3>; rel="next", <https://gitlab.example.com/api/v3/projects/8/issues/8/notes?page=1&per_page=3>; rel="first", <https://gitlab.example.com/api/v3/projects/8/issues/8/notes?page=3&per_page=3>; rel="last"
Status: 200 OK
Vary: Origin
X-Next-Page: 3
X-Page: 2
X-Per-Page: 3
X-Prev-Page: 1
X-Request-Id: 732ad4ee-9870-4866-a199-a9db0cde3c86
X-Runtime: 0.108688
X-Total: 8
X-Total-Pages: 3

Other pagination headers

Additional pagination headers are also sent back.

Header	Description
X-Total	The total number of items
X-Total-Pages	The total number of pages
X-Per-Page	The number of items per page
X-Page	The index of the current page (starting at 1)
X-Next-Page	The index of the next page
X-Prev-Page	The index of the previous page

id vs iid

When you work with the API, you may notice two similar fields in API entities: id and iid. The main difference between them is scope.

For example, an issue might have id: 46 and iid: 5.

Parameter	Description
id	Is unique across all issues and is used for any API call
iid	Is unique only in scope of a single project. When you browse issues or merge requests with the Web UI, you see the iid

That means that if you want to get an issue via the API you should use the id:

GET /projects/42/issues/:id

On the other hand, if you want to create a link to a web page you should use the iid:

GET /projects/42/issues/:iid

Data validation and error reporting

When working with the API you may encounter validation errors, in which case the API will answer with an HTTP 400 status.

Such errors appear in two cases:

• A required attribute of the API request is missing, e.g., the title of an issue is not given
• An attribute did not pass the validation, e.g., user bio is too long

When an attribute is missing, you will get something like:

HTTP/1.1 400 Bad Request
Content-Type: application/json
{
    "message":"400 (Bad request) \"title\" not given"
}

When a validation error occurs, error messages will be different. They will hold all details of validation errors:

HTTP/1.1 400 Bad Request
Content-Type: application/json
{
    "message": {
        "bio": [
            "is too long (maximum is 255 characters)"
        ]
    }
}

This makes error messages more machine-readable. The format can be described as follows:

{
    "message": {
        "<property-name>": [
            "<error-message>",
            "<error-message>",
            ...
        ],
        "<embed-entity>": {
            "<property-name>": [
                "<error-message>",
                "<error-message>",
                ...
            ],
        }
    }
}

Clients

There are many unofficial GitLab API Clients for most of the popular programming languages. Visit the GitLab website for a complete list.