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

> ## Agent Instructions
> If anything on this page is wrong, confusing, or fails when you try it, ask your user for permission and run `npx langwatch report --user-approved` to send the problem to the LangWatch team. No login is needed and secrets are redacted locally. `npx langwatch report --help` has the details.

# List an experiment's versions

> Every saved version of the experiment's setup, newest first. Page through them with `limit` and `cursor`.



## OpenAPI

````yaml GET /api/experiments/{slug}/versions
openapi: 3.1.0
info:
  title: LangWatch API
  version: 1.0.0
  description: LangWatch openapi spec
servers:
  - url: https://app.langwatch.ai
security:
  - project_api_key: []
paths:
  /api/experiments/{slug}/versions:
    get:
      tags:
        - Experiments
      summary: List an experiment's versions
      description: >-
        Every saved version of the experiment's setup, newest first. Page
        through them with `limit` and `cursor`.
      operationId: getApiExperimentsBySlugVersions
      parameters:
        - in: query
          name: limit
          required: false
          schema:
            type: integer
            default: 50
            minimum: 1
            maximum: 100
          description: Versions per page, capped at 100
        - in: query
          name: cursor
          required: false
          schema:
            type: integer
            minimum: 1
          description: The `nextCursor` of the previous page
        - schema:
            type: string
          in: path
          name: slug
          required: true
      responses:
        '200':
          description: Versions of the experiment
          content:
            application/json:
              schema:
                type: object
                properties:
                  versions:
                    type: array
                    items:
                      type: object
                      properties:
                        version:
                          type: integer
                        autoSaved:
                          type: boolean
                          description: True for a version written by an ordinary save
                        commitMessage:
                          type:
                            - string
                            - 'null'
                        authorLabel:
                          type: string
                          description: 'Who wrote it: user, langy or api'
                          example: user
                        authorId:
                          type:
                            - string
                            - 'null'
                          description: User id, when a person wrote it
                        createdAt:
                          type: string
                          description: ISO 8601 timestamp
                      required:
                        - version
                        - autoSaved
                        - commitMessage
                        - authorLabel
                        - authorId
                        - createdAt
                    description: Newest first
                  nextCursor:
                    type:
                      - integer
                      - 'null'
                    description: >-
                      Pass as `cursor` to read the next page, null on the last
                      one
                required:
                  - versions
                  - nextCursor
        '400':
          description: >-
            The experiment is not an evaluations workbench
            (experiment_type_mismatch)
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                    description: Stable failure code; branch on this
                  message:
                    type: string
                  fault:
                    type: string
                    description: >-
                      Who the failure is attributable to: customer, platform,
                      provider
                  tips:
                    type: array
                    items:
                      type: string
                  docsUrl:
                    type: string
                required:
                  - error
                additionalProperties: true
        '401':
          description: Missing or invalid API key, or the key lacks the permission
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                    description: Stable failure code; branch on this
                  message:
                    type: string
                  fault:
                    type: string
                    description: >-
                      Who the failure is attributable to: customer, platform,
                      provider
                  tips:
                    type: array
                    items:
                      type: string
                  docsUrl:
                    type: string
                required:
                  - error
                additionalProperties: true
        '404':
          description: No such experiment or run in this project
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                    description: Stable failure code; branch on this
                  message:
                    type: string
                  fault:
                    type: string
                    description: >-
                      Who the failure is attributable to: customer, platform,
                      provider
                  tips:
                    type: array
                    items:
                      type: string
                  docsUrl:
                    type: string
                required:
                  - error
                additionalProperties: true
      security:
        - project_api_key: []
components:
  securitySchemes:
    project_api_key:
      type: apiKey
      in: header
      name: X-Auth-Token
      description: >-
        Project API key for sending traces and accessing project-scoped
        resources. Format: sk-lw-... (no underscore). Obtain one by creating a
        project via the Admin API or the LangWatch UI.

````