# path-segment-plural

Enforces plural path segments.

| OAS | Compatibility |
|  --- | --- |
| 2.0 | ✅ |
| 3.0 | ✅ |
| 3.1 | ✅ |


## API design principles

RESTful API design often uses resources in path segments and those resources are typically plural.

For example, "customers" instead of "customer" because:

- `GET /customers` means getting a collection of customers
- `GET /customers/abc` means getting customer ABC from the customers collection


As your API grows, you may hit some false positives and may also need to ignore a few outliers.
That is, unless you're a purist.
Nothing wrong with that.

## Configuration

| Option | Type | Description |
|  --- | --- | --- |
| severity | string | Possible values: `off`, `warn`, `error`. Default `off` (in `recommended` configuration). |
| ignoreLastPathSegment | boolean | Ignores the last path segment if true. Default value: `false`. |
| exceptions | [string] | List of strings to exclude when checking path segments, for example, `v1`. |


An example configuration:


```yaml
rules:
  path-segment-plural: error
```

Another example configuration:


```yaml
rules:
  path-segment-plural:
    severity: error
    ignoreLastPathSegment: true
    exceptions:
      - v1
      - v2
      - people
```

## Examples

Given this configuration:


```yaml
rules:
  path-segment-plural: error
```

Example of an **incorrect** path segment:


```yaml
paths:
  /customer/{id}:
    post:
      parameters:
        - name: id
          in: path
          required: true
```

Example of a **correct** path segment:


```yaml
paths:
  /customers/{id}:
    post:
      parameters:
        - name: id
          in: path
          required: true
          description: The customer's ID.
```

## Related rules

- [path-excludes-patterns](/docs/cli/v1/rules/oas/path-excludes-patterns)
- [paths-kebab-case](/docs/cli/v1/rules/oas/paths-kebab-case)
- [configurable rules](/docs/cli/v1/rules/configurable-rules)


## Resources

- [Rule source](https://github.com/Redocly/redocly-cli/blob/main/packages/core/src/rules/common/path-segment-plural.ts)
- [Paths docs](https://redocly.com/docs/openapi-visual-reference/paths/)