path: root/doc/development/documentation/restful_api_styleguide.md

---
info: For assistance with this Style Guide page, see https://handbook.gitlab.com/handbook/product/ux/technical-writing/#assignments-to-other-projects-and-subjects.
stage: none
group: unassigned
description: 'Writing styles, markup, formatting, and other standards for the GitLab RESTful APIs.'
---

# Documenting REST API resources

REST API resources are documented in Markdown under
[`/doc/api`](https://gitlab.com/gitlab-org/gitlab/-/tree/master/doc/api). Each
resource has its own Markdown file, which is linked from
[`api_resources.md`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/api/api_resources.md).

When modifying the Markdown, also update the corresponding
[OpenAPI definition](https://gitlab.com/gitlab-org/gitlab/-/tree/master/doc/api/openapi)
if one exists for the resource. If not, consider creating one. Match the latest
[OpenAPI 3.0.x specification](https://swagger.io/specification/). (For more
information, see the discussion in this
[issue](https://gitlab.com/gitlab-org/gitlab/-/issues/16023#note_370901810).)

In the Markdown doc for a resource (AKA endpoint):

- Every method must have the REST API request. For example:

  ```plaintext
  GET /api/v4/projects/:id/repository/branches
  ```

- Every method must have a detailed [description of the attributes](#method-description).
- Every method must have a cURL example.
- Every method must have a detailed [description of the response body](#response-body-description).
- Every method must have a response body example (in JSON format).
- If an attribute is available only to higher level tiers than the other
  attributes, add the appropriate tier to the description. If an attribute is
  for Premium, include that it's also available for Ultimate.

After a new API documentation page is added, [add an entry in the global navigation](site_architecture/global_nav.md#add-a-navigation-entry). [Example](https://gitlab.com/gitlab-org/gitlab-docs/-/merge_requests/3497).

## API topic template

Use the following template to help you get started. Be sure to list any
required attributes first in the table.

````markdown
## API name

> Version history note.

One or two sentence description of what endpoint does.

### Method title

> Version history note.

Description of the method.

```plaintext
METHOD /api/v4/endpoint
```

Supported attributes:

| Attribute                | Type     | Required | Description           |
|--------------------------|----------|----------|-----------------------|
| `attribute`              | datatype | Yes      | Detailed description. |
| `attribute`              | datatype | No       | Detailed description. |
| `attribute`              | datatype | No       | Detailed description. |
| `attribute`              | datatype | No       | Detailed description. |

If successful, returns [`<status_code>`](rest/index.md#status-codes) and the following
response attributes:

| Attribute                | Type     | Description           |
|--------------------------|----------|-----------------------|
| `attribute`              | datatype | Detailed description. |
| `attribute`              | datatype | Detailed description. |

Example request:

```shell
curl --header "PRIVATE-TOKEN: <your_access_token>" \
  --url "https://gitlab.example.com/api/v4/endpoint?parameters"
```

Example response:

```json
[
  {
  }
]
```
````

## Version history

Add [version history](versions.md#documenting-version-specific-features)
to describe new or updated API calls.

To add version history for an individual attribute, include it in the version history
for the section. For example:

```markdown
### Edit a widget

> `widget_message` [introduced](<link-to-issue>) in GitLab 14.3.
```

If the API or attribute is deployed behind a feature flag,
[include the feature flag information](feature_flags.md) in the version history.

## Deprecations

To document the deprecation of an API endpoint, follow the steps to
[deprecate a page or topic](versions.md#deprecate-a-page-or-topic).

To deprecate an attribute:

1. Add a version history note.

   ```markdown
   > - `widget_name` [deprecated](<link-to-issue>) in GitLab 14.7.
   ```

1. Add inline deprecation text to the description.

   ```markdown
   | Attribute     | Type   | Required | Description |
   |---------------|--------|----------|-------------|
   | `widget_name` | string | No       | [Deprecated](<link-to-issue>) in GitLab 14.7 and is planned for removal in 15.4. Use `widget_id` instead. The name of the widget. |
   ```

To widely announce a deprecation, or if it's a breaking change,
[update the REST API deprecations and removals page](../../api/rest/deprecations.md).

## Method description

Use the following table headers to describe the methods. Attributes should
always be in code blocks using backticks (`` ` ``).

Sort the table by required attributes first, then alphabetically.

```markdown
| Attribute                    | Type          | Required | Description                                         |
|------------------------------|---------------|----------|-----------------------------------------------------|
| `title`                      | string        | Yes      | Title of the issue.                                 |
| `assignee_ids`               | integer array | No       | IDs of the users to assign the issue to. Ultimate only. |
| `confidential`               | boolean       | No       | Sets the issue to confidential. Default is `false`. |
```

Rendered example:

| Attribute                    | Type          | Required | Description                                         |
|------------------------------|---------------|----------|-----------------------------------------------------|
| `title`                      | string        | Yes      | Title of the issue.                                 |
| `assignee_ids`               | integer array | No       | IDs of the users to assign the issue to. Premium and Ultimate only. |
| `confidential`               | boolean       | No       | Sets the issue to confidential. Default is `false`. |

For information about writing attribute descriptions, see the [GraphQL API description style guide](../api_graphql_styleguide.md#description-style-guide).

## Response body description

Start the description with the following sentence, replacing `status code` with the
relevant [HTTP status code](../../api/rest/index.md#status-codes), for example:

```markdown
If successful, returns [`200 OK`](../../api/rest/index.md#status-codes) and the
following response attributes:
```

Use the following table headers to describe the response bodies. Attributes should
always be in code blocks using backticks (`` ` ``).

If the attribute is a complex type, like another object, represent sub-attributes
with dots (`.`), like `project.name` or `projects[].name` in case of an array.

Sort the table alphabetically.

```markdown
| Attribute                    | Type          | Description                               |
|------------------------------|---------------|-------------------------------------------|
| `assignee_ids`               | integer array | IDs of the users to assign the issue to. Premium and Ultimate only. |
| `confidential`               | boolean       | Whether the issue is confidential or not. |
| `title`                      | string        | Title of the issue.                       |
```

Rendered example:

| Attribute                    | Type          | Description                               |
|------------------------------|---------------|-------------------------------------------|
| `assignee_ids`               | integer array | IDs of the users to assign the issue to. Premium and Ultimate only. |
| `confidential`               | boolean       | Whether the issue is confidential or not. |
| `title`                      | string        | Title of the issue.                       |

For information about writing attribute descriptions, see the [GraphQL API description style guide](../api_graphql_styleguide.md#description-style-guide).

## cURL commands

- Use `https://gitlab.example.com/api/v4/` as an endpoint.
- Wherever needed use this personal access token: `<your_access_token>`.
- Always put the request first. `GET` is the default so you don't have to
  include it.
- Use long option names (`--header` instead of `-H`) for legibility. (Tested in
  [`scripts/lint-doc.sh`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/scripts/lint-doc.sh).)
- Declare URLs with the `--url` parameter, and wrap the URL in double quotes (`"`).
- Prefer to use examples using the personal access token and don't pass data of
  username and password.
- For legibility, use the <code>&#92;</code> character and indentation to break long single-line
  commands apart into multiple lines.

| Methods                                         | Description                                            |
|-------------------------------------------------|--------------------------------------------------------|
| `--header "PRIVATE-TOKEN: <your_access_token>"` | Use this method as is, whenever authentication needed. |
| `--request POST`                                | Use this method when creating new objects.             |
| `--request PUT`                                 | Use this method when updating existing objects.        |
| `--request DELETE`                              | Use this method when removing existing objects.        |

## cURL Examples

The following sections include a set of [cURL](https://curl.se/) examples
you can use in the API documentation.

WARNING:
Do not use information for real users, URLs, or tokens. For documentation, refer to our
relevant style guide sections on [Fake user information](styleguide/index.md#fake-user-information),
[Fake URLs](styleguide/index.md#fake-urls), and [Fake tokens](styleguide/index.md#fake-tokens).

### Simple cURL command

Get the details of a group:

```shell
curl --header "PRIVATE-TOKEN: <your_access_token>" \
  --url "https://gitlab.example.com/api/v4/groups/gitlab-org"
```

### cURL example with parameters passed in the URL

Create a new project under the authenticated user's namespace:

```shell
curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" \
  --url "https://gitlab.example.com/api/v4/projects?name=foo"
```

### Post data using cURL's `--data`

Instead of using `--request POST` and appending the parameters to the URI, you
can use cURL's `--data` option. The example below will create a new project
`foo` under the authenticated user's namespace.

```shell
curl --data "name=foo" \
  --header "PRIVATE-TOKEN: <your_access_token>" \
  --url "https://gitlab.example.com/api/v4/projects"
```

### Post data using JSON content

This example creates a new group. Be aware of the use of single (`'`) and double
(`"`) quotes.

```shell
curl --request POST \
  --header "PRIVATE-TOKEN: <your_access_token>" \
  --header "Content-Type: application/json" \
  --data '{"path": "my-group", "name": "My group"}' \
  --url "https://gitlab.example.com/api/v4/groups"
```

For readability, you can also set up the `--data` by using the following format:

```shell
curl --request POST \
  --url "https://gitlab.example.com/api/v4/groups" \
  --header "content-type: application/json" \
  --header "PRIVATE-TOKEN: <your_access_token>" \
  --data '{
    "path": "my-group",
    "name": "My group"
}'
```

### Post data using form-data

Instead of using JSON or URL-encoding data, you can use `multipart/form-data` which
properly handles data encoding:

```shell
curl --request POST \
  --header "PRIVATE-TOKEN: <your_access_token>" \
  --form "title=ssh-key" \
  --form "key=ssh-rsa AAAAB3NzaC1yc2EA..." \
  --url "https://gitlab.example.com/api/v4/users/25/keys"
```

The above example is run by and administrator and will add an SSH public key
titled `ssh-key` to user's account which has an ID of 25.

### Escape special characters

Spaces or slashes (`/`) may sometimes result to errors, thus it is recommended
to escape them when possible. In the example below we create a new issue which
contains spaces in its title. Observe how spaces are escaped using the `%20`
ASCII code.

```shell
curl --request POST \
  --header "PRIVATE-TOKEN: <your_access_token>" \
  --url "https://gitlab.example.com/api/v4/projects/42/issues?title=Hello%20GitLab"
```

Use `%2F` for slashes (`/`).

### Pass arrays to API calls

The GitLab API sometimes accepts arrays of strings or integers. For example, to
exclude specific users when requesting a list of users for a project, you would
do something like this:

```shell
curl --request PUT \
  --header "PRIVATE-TOKEN: <your_access_token>"
  --data "skip_users[]=<user_id>" \
  --data "skip_users[]=<user_id>" \
  --url "https://gitlab.example.com/api/v4/projects/<project_id>/users"
```