gitlab-org--gitlab-foss/doc/api
Andreas Brandl f5ba7ac357 Merge branch 'osw-multi-line-suggestions-creation-strategy' into 'master'
Prepares suggestion implementation for multi-line support

See merge request gitlab-org/gitlab-ce!26057
2019-03-27 16:57:25 +00:00
..
graphql Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
releases Docs: Fix missed or newly added broken anchors 2019-03-25 04:56:57 +00:00
templates Refactor of API landing page 2019-02-15 09:39:23 +00:00
access_requests.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
applications.md Add more information and refactor format of topic 2019-01-11 15:38:15 +00:00
avatar.md Add more information and refactor format of Avatar API topic 2019-01-15 18:27:21 +00:00
award_emoji.md API: Clarify the award emoji docs 2019-02-13 20:25:12 +01:00
boards.md Added missing comma in sample response json for list of boards and a single board 2019-02-20 10:52:57 +00:00
branches.md Fix branch API table format 2019-02-11 12:08:13 +00:00
broadcast_messages.md Refactor broadcast message API page 2019-02-05 13:49:11 +10:00
build_triggers.md Docs: Add automatic redirects to last batch of moved files 2019-03-26 17:21:22 +00:00
builds.md Docs: Add automatic redirects to last batch of moved files 2019-03-26 17:21:22 +00:00
commits.md Docs: Fix missed or newly added broken anchors 2019-03-25 04:56:57 +00:00
container_registry.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
custom_attributes.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
deploy_key_multiple_projects.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
deploy_keys.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
deployments.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
discussions.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
environments.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
events.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
features.md Allow setting feature flags per GitLab group 2019-02-19 14:57:03 +08:00
group_badges.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
group_boards.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
group_labels.md API: Expose text_color for project and group labels 2019-02-12 19:36:45 +01:00
group_level_variables.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
group_milestones.md Resolve "Get milestone by title via API" 2019-03-27 09:01:07 +00:00
groups.md Add group full path to project's shared_with_groups 2019-01-15 21:09:05 +01:00
import.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
issues.md Merge branch 'filter-confidential-issues' into 'master' 2019-02-26 12:24:39 +01:00
jobs.md API: delete job_artifacts of a single job 2019-03-06 11:06:21 +00:00
keys.md add user's public_email attribute to api 2018-09-27 11:33:55 +02:00
labels.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
lint.md Refactor of API landing page 2019-02-15 09:39:23 +00:00
markdown.md
members.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
merge_requests.md Add API support for refreshing merge ref path 2019-02-26 12:37:32 -03:00
milestones.md Resolve "Get milestone by title via API" 2019-03-27 09:01:07 +00:00
namespaces.md Docs: Add link to namespace api doc to clarify URL-encoded path 2019-03-15 09:55:20 +00:00
notes.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
notification_settings.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
oauth2.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
pages_domains.md Refactor of API landing page 2019-02-15 09:39:23 +00:00
pipeline_schedules.md Copyedit pipelines-related documentation 2019-03-19 08:17:16 +00:00
pipeline_triggers.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
pipelines.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
project_badges.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
project_clusters.md Change non-standard NBSP space to regular SP space 2019-01-30 10:43:39 +00:00
project_import_export.md Refactor of API landing page 2019-02-15 09:39:23 +00:00
project_level_variables.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
project_snippets.md Fix note lists throughout docs 2019-03-20 13:45:15 +00:00
project_statistics.md Add project http fetch statistics API 2019-02-27 11:52:35 +01:00
project_templates.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
projects.md Let users set name/path on project fork using API 2019-02-20 00:19:27 +05:30
protected_branches.md Refactor of API landing page 2019-02-15 09:39:23 +00:00
protected_tags.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
README.md Docs: Last batch of misc broken anchors 2019-03-04 02:37:14 +00:00
repositories.md Added example for get file archive 2019-02-12 12:31:33 +00:00
repository_files.md Ensure all lists are surrounded by new lines 2019-02-22 13:17:10 +00:00
repository_storage_health.md Remove Git circuit breaker 2018-10-10 09:08:18 +02:00
repository_submodules.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
resource_label_events.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
runners.md add tag_list param to runners api 2019-02-27 20:19:49 +01:00
search.md Merge branch 'feature/users-search-results' into 'master' 2019-03-19 10:30:08 +00:00
services.md Fix note lists throughout docs 2019-03-20 13:45:15 +00:00
settings.md Add Saturday to first day of the week 2019-03-04 07:52:15 +03:30
sidekiq_metrics.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
snippets.md Refactor snippets API documentation page 2019-02-08 13:57:31 +00:00
suggestions.md Prepare suggestion implementation for multi-line 2019-03-27 12:26:53 -03:00
system_hooks.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
tags.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00
todos.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
users.md Add highest_role method to User 2019-03-22 09:54:03 +00:00
v3_to_v4.md Resolve "CE documentation is not CommonMark compliant" 2018-09-06 16:52:18 +00:00
version.md Replace look-alike token with '<your_access_token>' 2019-01-04 13:19:27 +01:00
wikis.md Remove consecutive blank lines from markdown files 2019-02-18 09:36:13 +00:00

GitLab API

Automate GitLab via a simple and powerful API.

The main GitLab API is a REST API. Therefore, documentation in this section assumes knowledge of REST concepts.

API resources

Available API resources can be grouped in the following contexts:

See also:

Project resources

The following API resources are available in the project context:

Resource Available endpoints
Access requests /projects/:id/access_requests (also available for groups)
Award emoji /projects/:id/issues/.../award_emoji, /projects/:id/merge_requests/.../award_emoji, /projects/:id/snippets/.../award_emoji
Branches /projects/:id/repository/branches/, /projects/:id/repository/merged_branches
Commits /projects/:id/repository/commits, /projects/:id/statuses
Container Registry /projects/:id/registry/repositories
Custom attributes /projects/:id/custom_attributes (also available for groups and users)
Deploy keys /projects/:id/deploy_keys (also available standalone)
Deployments /projects/:id/deployments
Discussions (threaded comments) /projects/:id/issues/.../discussions, /projects/:id/snippets/.../discussions, /projects/:id/merge_requests/.../discussions, /projects/:id/commits/.../discussions
Environments /projects/:id/environments
Events /projects/:id/events (also available for users and standalone)
Issues /projects/:id/issues (also available for groups and standalone)
Issue boards /projects/:id/boards
Jobs /projects/:id/jobs, /projects/:id/pipelines/.../jobs
Labels /projects/:id/labels
Members /projects/:id/members (also available for groups)
Merge requests /projects/:id/merge_requests (also available for groups and standalone)
Notes (comments) /projects/:id/issues/.../notes, /projects/:id/snippets/.../notes, /projects/:id/merge_requests/.../notes
Notification settings /projects/:id/notification_settings (also available for groups and standalone)
Pages domains /projects/:id/pages (also available standalone)
Pipelines /projects/:id/pipelines
Pipeline schedules /projects/:id/pipeline_schedules
Pipeline triggers /projects/:id/triggers
Projects including setting Webhooks /projects, /projects/:id/hooks (also available for users)
Project badges /projects/:id/badges
Project clusters /projects/:id/clusters
Project-level variables /projects/:id/variables
Project import/export /projects/:id/export, /projects/import, /projects/:id/import
Project milestones /projects/:id/milestones
Project snippets /projects/:id/snippets
Project templates /projects/:id/templates
Protected branches /projects/:id/protected_branches
Protected tags /projects/:id/protected_tags
Releases /projects/:id/releases
Release links /projects/:id/releases/.../assets/links
Repositories /projects/:id/repository
Repository files /projects/:id/repository/files
Repository submodules /projects/:id/repository/submodules
Resource label events /projects/:id/issues/.../resource_label_events, /projects/:id/merge_requests/.../resource_label_events
Runners /projects/:id/runners (also available standalone)
Search /projects/:id/search (also available for groups and standalone)
Services /projects/:id/services
Tags /projects/:id/repository/tags
Wikis /projects/:id/wikis

Group resources

The following API resources are available in the group context:

Resource Available endpoints
Access requests /groups/:id/access_requests/ (also available for projects)
Custom attributes /groups/:id/custom_attributes (also available for projects and users)
Groups /groups, /groups/.../subgroups
Group badges /groups/:id/badges
Group issue boards /groups/:id/boards
Group labels /groups/:id/labels
Group-level variables /groups/:id/variables
Group milestones /groups/:id/milestones
Issues /groups/:id/issues (also available for projects and standalone)
Members /groups/:id/members (also available for projects)
Merge requests /groups/:id/merge_requests (also available for projects and standalone)
Notification settings /groups/:id/notification_settings (also available for projects and standalone)
Search /groups/:id/search (also available for projects and standalone)

Standalone resources

The following API resources are available outside of project and group contexts (including /users):

Resource Available endpoints
Applications /applications
Avatar /avatar
Broadcast messages /broadcast_messages
Code snippets /snippets
Custom attributes /users/:id/custom_attributes (also available for groups and projects)
Deploy keys /deploy_keys (also available for projects)
Events /events, /users/:id/events (also available for projects)
Feature flags /features
Import repository from GitHub /import/github
Issues /issues (also available for groups and projects)
Keys /keys
Markdown /markdown
Merge requests /merge_requests (also available for groups and projects)
Namespaces /namespaces
Notification settings /notification_settings (also available for groups and projects)
Pages domains /pages/domains (also available for projects)
Projects /users/:id/projects (also available for projects)
Runners /runners (also available for projects)
Search /search (also available for groups and projects)
Settings /application/settings
Sidekiq metrics /sidekiq
Suggestions /suggestions
System hooks /hooks
Todos /todos
Users /users
Validate .gitlab-ci.yml file /lint
Version /version

Templates API resources

Endpoints are available for:

Road to GraphQL

Going forward, we will start on moving to GraphQL and deprecate the use of controller-specific endpoints. GraphQL has a number of benefits:

  1. We avoid having to maintain two different APIs.
  2. Callers of the API can request only what they need.
  3. It is versioned by default.

It will co-exist with the current v4 REST API. If we have a v5 API, this should be a compatibility layer on top of GraphQL.

Although there were some patenting and licensing concerns with GraphQL, these have been resolved to our satisfaction by the relicensing of the reference implementations under MIT, and the use of the OWF license for the GraphQL specification.

Compatibility guidelines

The HTTP API is versioned using a single number, the current one being 4. This number symbolizes the same as the major version number as described by SemVer. This mean that backward incompatible changes will require this version number to change. However, the minor version is not explicit. This allows for a stable API endpoint, but also means new features can be added to the API in the same version number.

New features and bug fixes are released in tandem with a new GitLab, and apart from incidental patch and security releases, are released on the 22nd of each month. Backward incompatible changes (e.g. endpoints removal, parameters removal etc.), as well as removal of entire API versions are done in tandem with a major point release of GitLab itself. All deprecations and changes between two versions should be listed in the documentation. For the changes between v3 and v4; please read the v3 to v4 documentation

Current status

Currently only API version v4 is available. Version v3 was removed in GitLab 11.0.

Basic usage

API requests should be prefixed with api and the API version. The API version is defined in lib/api.rb. For example, the root of the v4 API is at /api/v4.

Example of a valid API request using cURL:

curl "https://gitlab.example.com/api/v4/projects"

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

Authentication

Most API requests require authentication, or will only return public data when authentication is not provided. For those cases where it is not required, this will be mentioned in the documentation for each individual endpoint. For example, the /projects/:id endpoint.

There are three ways to authenticate with the GitLab API:

  1. OAuth2 tokens
  2. Personal access tokens
  3. Session cookie

For admins who want to authenticate with the API as a specific user, or who want to build applications or scripts that do so, two options are available:

  1. Impersonation tokens
  2. Sudo

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

{
  "message": "401 Unauthorized"
}

OAuth2 tokens

You can use an OAuth2 token to authenticate with the API by passing it in either the access_token parameter or the Authorization header.

Example of using the OAuth2 token in a parameter:

curl https://gitlab.example.com/api/v4/projects?access_token=OAUTH-TOKEN

Example of using the OAuth2 token in a header:

curl --header "Authorization: Bearer OAUTH-TOKEN" https://gitlab.example.com/api/v4/projects

Read more about GitLab as an OAuth2 provider.

Personal access tokens

You can use a personal access token to authenticate with the API by passing it in either the private_token parameter or the Private-Token header.

Example of using the personal access token in a parameter:

curl https://gitlab.example.com/api/v4/projects?private_token=<your_access_token>

Example of using the personal access token in a header:

curl --header "Private-Token: <your_access_token>" https://gitlab.example.com/api/v4/projects

Read more about personal access tokens.

When signing in to the main GitLab application, a _gitlab_session cookie is set. The API will use this cookie for authentication if it is present, but using the API to generate a new session cookie is currently not supported.

The primary user of this authentication method is the web frontend of GitLab itself, which can use the API as the authenticated user to get a list of their projects, for example, without needing to explicitly pass an access token.

Impersonation tokens

Introduced in GitLab 9.0. Needs admin permissions.

Impersonation tokens are a type of personal access token that can only be created by an admin for a specific user. They are a great fit if you want to build applications or scripts that authenticate with the API as a specific user.

They are an alternative to directly using the user's password or one of their personal access tokens, and to using the Sudo feature, since the user's (or admin's, in the case of Sudo) password/token may not be known or may change over time.

For more information, refer to the users API docs.

Impersonation tokens are used exactly like regular personal access tokens, and can be passed in either the private_token parameter or the Private-Token header.

Disable impersonation

Introduced in GitLab 11.6.

By default, impersonation is enabled. To disable impersonation:

For Omnibus installations

  1. Edit /etc/gitlab/gitlab.rb:

    gitlab_rails['impersonation_enabled'] = false
    
  2. Save the file and reconfigure GitLab for the changes to take effect.

To re-enable impersonation, remove this configuration and reconfigure GitLab.


For installations from source

  1. Edit config/gitlab.yml:

    gitlab:
      impersonation_enabled: false
    
  2. Save the file and restart GitLab for the changes to take effect.

To re-enable impersonation, remove this configuration and restart GitLab.

Sudo

NOTE: Note: Only available to administrators.

All API requests support performing an API call as if you were another user, provided you are authenticated as an administrator with an OAuth or Personal Access Token that has the sudo scope.

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.

NOTE: Note: Usernames are case insensitive.

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

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

If an access token without the sudo scope is provided, an error message will be returned with status code 403:

{
  "error": "insufficient_scope",
  "error_description": "The request requires higher privileges than provided by the access token.",
  "scope": "sudo"
}

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

{
  "message": "404 User with ID or username '123' Not Found"
}

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

GET /projects?private_token=<your_access_token>&sudo=username
curl --header "Private-Token: <your_access_token>" --header "Sudo: username" "https://gitlab.example.com/api/v4/projects"

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

GET /projects?private_token=<your_access_token>&sudo=23
curl --header "Private-Token: <your_access_token>" --header "Sudo: 23" "https://gitlab.example.com/api/v4/projects"

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 Return 200 OK if the resource is accessed or modified successfully. The (modified) result is returned as JSON.
DELETE Returns 204 No Content if the resource was deleted successfully.

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.
204 No Content The server has successfully fulfilled the request and that there is no additional content to send in the response payload body.
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.
412 Indicates the request was denied. May happen if the If-Unmodified-Since header is provided when trying to delete a resource, which was modified in between.
422 Unprocessable The entity could not be processed.
500 Server Error While handling the request something went wrong server-side.

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 --request PUT --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/namespaces?per_page=50

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 --head --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/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/v4/projects/8/issues/8/notes?page=1&per_page=3>; rel="prev", <https://gitlab.example.com/api/v4/projects/8/issues/8/notes?page=3&per_page=3>; rel="next", <https://gitlab.example.com/api/v4/projects/8/issues/8/notes?page=1&per_page=3>; rel="first", <https://gitlab.example.com/api/v4/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

CAUTION: Caution: For performance reasons since GitLab 11.8 and behind the api_kaminari_count_with_limit feature flag, if the number of resources is more than 10,000, the X-Total and X-Total-Pages headers as well as the rel="last" Link are not present in the response headers.

Namespaced path encoding

If using namespaced API calls, make sure that the NAMESPACE/PROJECT_NAME is URL-encoded.

For example, / is represented by %2F:

GET /api/v4/projects/diaspora%2Fdiaspora

Branches and tags name encoding

If your branch or tag contains a /, make sure the branch/tag name is URL-encoded.

For example, / is represented by %2F:

GET /api/v4/projects/1/branches/my%2Fbranch/commits

Encoding API parameters of array and hash types

We can call the API with array and hash types parameters as shown below:

array

import_sources is a parameter of type array:

curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" \
-d "import_sources[]=github" \
-d "import_sources[]=bitbucket" \
"https://gitlab.example.com/api/v4/some_endpoint

hash

override_params is a parameter of type hash:

curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" \
--form "namespace=email" \
--form "path=impapi" \
--form "file=@/path/to/somefile.txt"
--form "override_params[visibility]=private" \
--form "override_params[some_other_param]=some_value" \
https://gitlab.example.com/api/v4/projects/import

Array of hashes

variables is a parameter of type array containing hash key/value pairs [{ 'key' => 'UPLOAD_TO_S3', 'value' => 'true' }]:

curl --globoff --request POST --header "PRIVATE-TOKEN: ********************" \
"https://gitlab.example.com/api/v4/projects/169/pipeline?ref=master&variables[][key]=VAR1&variables[][value]=hello&variables[][key]=VAR2&variables[][value]=world"

curl --request POST --header "PRIVATE-TOKEN: ********************" \
--header "Content-Type: application/json" \
--data '{ "ref": "master", "variables": [ {"key": "VAR1", "value": "hello"}, {"key": "VAR2", "value": "world"} ] }' \
"https://gitlab.example.com/api/v4/projects/169/pipeline"

id vs iid

Some resources have two similarly-named fields. For example, issues, merge requests, and project milestones. The fields are:

  • id: ID that is unique across all projects.
  • iid: additional, internal ID that is unique in the scope of a single project.

NOTE: Note: The iid is displayed in the web UI.

If a resource has the iid field and the id field, the iid field is usually used instead of id to fetch the resource.

For example, suppose a project with id: 42 has an issue with id: 46 and iid: 5. In this case:

  • A valid API call to retrieve the issue is GET /projects/42/issues/5
  • An invalid API call to retrieve the issue is GET /projects/42/issues/46.

NOTE: Note: Not all resources with the iid field are fetched by iid. For guidance on which field to use, see the documentation for the specific resource.

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>",
                ...
            ],
        }
    }
}

Unknown route

When you try to access an API URL that does not exist you will receive 404 Not Found.

HTTP/1.1 404 Not Found
Content-Type: application/json
{
    "error": "404 Not Found"
}

Encoding + in ISO 8601 dates

If you need to include a + in a query parameter, you may need to use %2B instead due to a W3 recommendation that causes a + to be interpreted as a space. For example, in an ISO 8601 date, you may want to pass a time in Mountain Standard Time, such as:

2017-10-17T23:11:13.000+05:30

The correct encoding for the query parameter would be:

2017-10-17T23:11:13.000%2B05:30

Clients

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