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

# List dated API versions

> Every dated version this deployment serves, oldest first.

Send one as `X-Mesh-Version` to pin a request, or store it on an API key to pin
every request that key makes. Omit it and you get the `baseline` entry.

An unsupported or malformed value is rejected with `400 invalid_api_version`
rather than falling back silently, so a typo cannot leave you believing you are
pinned when you are not.



## OpenAPI

````yaml /api/openapi.json get /v1/api-versions
openapi: 3.1.0
info:
  title: MeshAPI
  description: One key, all AI models.
  version: 0.1.0
servers:
  - url: https://api.meshapi.ai
security:
  - BearerAuth: []
paths:
  /v1/api-versions:
    get:
      tags:
        - API Versions
      summary: List dated API versions
      description: >-
        Every dated version this deployment serves, oldest first.


        Send one as `X-Mesh-Version` to pin a request, or store it on an API key
        to pin

        every request that key makes. Omit it and you get the `baseline` entry.


        An unsupported or malformed value is rejected with `400
        invalid_api_version`

        rather than falling back silently, so a typo cannot leave you believing
        you are

        pinned when you are not.
      operationId: list_api_versions
      parameters:
        - in: header
          name: X-Mesh-Version
          required: false
          schema:
            type: string
            enum:
              - 2026-08
            default: 2026-08
          example: 2026-08
          description: >-
            Dated version of the API contract to pin this request to. Omit it
            and the request is served under `2026-08` — the oldest supported
            version, so an existing integration is never moved by a release. A
            malformed or unsupported value is rejected with `400
            invalid_api_version` rather than falling back silently. The version
            actually served is echoed as `X-Mesh-Version` on every response,
            including errors.
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                items:
                  $ref: '#/components/schemas/ApiVersionOut'
                type: array
                title: Response List Api Versions
        '401':
          description: Missing or invalid credentials (user JWT or API key)
          content:
            application/json:
              example:
                error:
                  code: unauthorized
                  message: Invalid API key.
                request_id: req_01ARZ3NDEKTSV4RRFFQ69G5FAV
      security:
        - BearerAuth: []
components:
  schemas:
    ApiVersionOut:
      properties:
        label:
          type: string
          title: Label
          description: The value to send as `X-Mesh-Version`, e.g. `2026-08`.
        status:
          type: string
          title: Status
          description: '`ga` | `deprecated` | `sunset`.'
        released:
          type: string
          title: Released
          description: ISO date this version became available.
        deprecated_on:
          anyOf:
            - type: string
            - type: 'null'
          title: Deprecated On
          description: >-
            ISO date this version was deprecated, or null. Feeds the
            `Deprecation` response header.
        sunset_on:
          anyOf:
            - type: string
            - type: 'null'
          title: Sunset On
          description: >-
            ISO date this version stops being served, or null. Feeds the
            `Sunset` response header.
        notes_url:
          anyOf:
            - type: string
            - type: 'null'
          title: Notes Url
          description: Migration guide for leaving this version, or null.
        baseline:
          type: boolean
          title: Baseline
          description: >-
            True for the version a caller gets with no `X-Mesh-Version` header
            and no stored pin. This is the OLDEST supported version, so an
            existing integration is never moved by a release.
        latest:
          type: boolean
          title: Latest
          description: >-
            True for the newest released version. Note this is NOT the default —
            pin it explicitly to receive it.
      type: object
      required:
        - label
        - status
        - released
        - baseline
        - latest
      title: ApiVersionOut
      description: One dated version of the public contract.
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: >-
        Enter your MeshAPI key (`rsk_...`) — sent as `Authorization: Bearer
        <key>`.

````