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

# Launch an experiment

> Launches immediately using server time and runs indefinitely until an operator explicitly concludes it. There is no automatic end date or statistical stopping rule. Creates or reuses a monitor group and freezes its definitions for both versions. Zelto does not route callers. Requires Observability, the Experiments v2 rollout flag, and owner/admin access.



## OpenAPI

````yaml /docs-openapi.json post /v1/experiments
openapi: 3.1.0
info:
  title: Zelto REST API
  version: v1
  description: >-
    Programmatic access to your Zelto organization. Every endpoint is scoped to
    the organization the API key belongs to. Mint a key at Settings →
    Integrations → API Call Upload.
servers:
  - url: https://api.zelto.ai
    description: Production
security:
  - bearerAuth: []
tags:
  - name: Agents
    description: Voice and chat bots normalised through Zelto's ingestion pipeline.
  - name: Conversations
    description: Calls, chats, and voicemails — plus their transcripts and recordings.
  - name: Customer Metrics
    description: >-
      Customer-provided evaluations attached to a call (requires metrics
      enabled).
  - name: Reviews
    description: Human review state for conversations.
  - name: Buckets
    description: Reviewer routing — group conversations for batched review.
  - name: Companies
    description: Clients or brands your agents work for, and their logos.
  - name: Findings
    description: >-
      Structured issues discovered during analysis, with optional conversation
      attachments and comments.
  - name: Experiments
    description: >-
      Prospective measurement of two externally routed prompt versions across
      independent monitor outcomes.
  - name: Organizations
    description: >-
      Headless org provisioning. Requires an admin/service API key (not a
      read-only org-scoped customer key).
paths:
  /v1/experiments:
    post:
      tags:
        - Experiments
      summary: Launch an experiment
      description: >-
        Launches immediately using server time and runs indefinitely until an
        operator explicitly concludes it. There is no automatic end date or
        statistical stopping rule. Creates or reuses a monitor group and freezes
        its definitions for both versions. Zelto does not route callers.
        Requires Observability, the Experiments v2 rollout flag, and owner/admin
        access.
      operationId: createExperiment
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ExperimentCreate'
      responses:
        '201':
          description: Experiment launched.
        '400':
          $ref: '#/components/responses/ValidationFailed'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
components:
  schemas:
    ExperimentCreate:
      type: object
      required:
        - name
        - agentId
        - armAVersionId
        - armBVersionId
        - outcomeMetricIds
        - primaryMetricId
        - stableRoutingConfirmed
      properties:
        name:
          type: string
          minLength: 1
          maxLength: 255
        description:
          type:
            - string
            - 'null'
          maxLength: 2000
        agentId:
          type: string
          format: uuid
        armAVersionId:
          type: string
          format: uuid
        armBVersionId:
          type: string
          format: uuid
        armAName:
          type:
            - string
            - 'null'
          maxLength: 120
        armBName:
          type:
            - string
            - 'null'
          maxLength: 120
        cohortFilters:
          type: array
          maxItems: 12
          items:
            type: object
            additionalProperties: true
        assignmentUnit:
          oneOf:
            - type: object
              required:
                - kind
              properties:
                kind:
                  const: auto
            - type: object
              required:
                - kind
                - key
              properties:
                kind:
                  const: metadata
                key:
                  type: string
                  minLength: 1
                  maxLength: 120
        expectedArmAPercent:
          type: integer
          minimum: 1
          maximum: 99
          default: 50
        outcomeMetricIds:
          type: array
          minItems: 1
          items:
            type: string
            format: uuid
        primaryMetricId:
          type: string
          format: uuid
        monitorGroupId:
          type: string
          format: uuid
          description: >-
            Reuse a saved group from GET /v1/experiments/monitor-groups.
            outcomeMetricIds must match the group's current metricIds. Cannot be
            combined with newMonitorGroupName.
        newMonitorGroupName:
          type: string
          minLength: 1
          maxLength: 255
          description: >-
            Save outcomeMetricIds as a reusable organization group when
            launching. Cannot be combined with monitorGroupId.
        notifications:
          type: object
          properties:
            emails:
              type: array
              maxItems: 20
              items:
                type: string
                format: email
        stableRoutingConfirmed:
          const: true
          description: Confirms that traffic is assigned consistently outside Zelto.
    Error:
      type: object
      required:
        - error
      properties:
        error:
          type: string
          description: >-
            Human-readable error message, e.g. Unauthorized or Validation
            failed.
        message:
          type: string
        details:
          type: object
          additionalProperties: true
  responses:
    ValidationFailed:
      description: Request body failed validation.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Unauthorized:
      description: Missing or invalid API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Forbidden:
      description: >-
        The key is valid but not allowed to perform this operation (e.g. a
        read-only org-scoped customer key calling a service-only endpoint).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        Send `Authorization: Bearer YOUR_API_KEY`. The key resolves to a single
        organization.

````