> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appsignal.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Test authentication

For how to pass your token, see [Authentication](https://docs.appsignal.com/api/v2/overview.md#authentication).

```yaml GET /api/v2/auth theme={null}
openapi: 3.1.0
info:
  title: AppSignal V2 API
  description: >-
    REST API for metrics, traces, logs, Kubernetes monitoring, and deployment
    tracking.
  license:
    name: ''
  version: 0.1.0
paths:
  /api/v2/auth:
    get:
      tags:
        - System
      summary: Test authentication
      operationId: auth
      responses:
        '200':
          description: The token is valid.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AuthResponse'
        '400':
          description: Malformed request, or input the server cannot process.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/BadRequestResponse'
        '401':
          description: Missing or invalid authentication token.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '404':
          description: Route or resource not found.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '429':
          description: External query concurrency limit exceeded; retry shortly.
          headers:
            Retry-After:
              schema:
                type: integer
              description: Seconds to wait before retrying.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TooManyRequestsResponse'
        '500':
          description: Unhandled server-side failure.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      security:
        - bearer_auth: []
        - token_query: []
components:
  schemas:
    AuthResponse:
      type: object
      description: Response body for the authentication test endpoint.
      required:
        - message
      properties:
        message:
          type: string
          description: Confirmation message including the authenticated user ID.
      example:
        message: Authenticated user 6694fca622fa81b8dd2e7178
    BadRequestResponse:
      type: object
      description: >-
        Standard body for HTTP 400 Bad Request responses. Branch on the stable
        `error` slug, display `message` as-is, and read per-error structured
        data from `details`.
      required:
        - error
        - message
      properties:
        error:
          type: string
          description: Stable, machine-readable slug identifying the specific error case.
        message:
          type: string
          description: Human-readable message. Safe to log or display to end users.
        details:
          description: >-
            Per-error structured payload. Shape varies by
            [`error`](Self::error).
    ErrorResponse:
      type: object
      description: Error body returned for 401, 404 and 500 responses.
      required:
        - error
      properties:
        error:
          type: string
          description: Human-readable error message.
    TooManyRequestsResponse:
      type: object
      description: Error body returned for 429 responses.
      required:
        - error
      properties:
        error:
          type: string
          description: Human-readable error message.
        suggestion:
          type:
            - string
            - 'null'
          description: >-
            A cheaper way to write the request's filter. Only the trace list

            endpoints set it, and only for a filter with a known indexed
            rewrite.
  securitySchemes:
    bearer_auth:
      type: http
      scheme: bearer
      description: '`Authorization: Bearer <token>`'
    token_query:
      type: apiKey
      in: query
      name: token
      description: >-
        Alternative to the Authorization header: pass the token as a
        `?token=<token>` query parameter.
```


## API Specification

The full API specification for this endpoint is available in the [documentation index](https://docs.appsignal.com/llms.txt).


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