Retell AI Voice API

openapi: 3.0.1
info:
  title: Retell AI Agent Voice API
  description: REST API for building, testing, and deploying AI voice agents that make and receive phone and web calls. Configure a response engine (Retell LLM, a custom LLM, or a Conversation Flow), attach a voice, provision phone numbers, place outbound and web calls, run batch campaigns, ground agents with knowledge bases, and read back transcripts, recordings, and call analysis. All endpoints are authenticated with a Bearer API key.
  termsOfService: https://www.retellai.com/terms-of-service
  contact:
    name: Retell AI Support
    url: https://docs.retellai.com
  version: '2.0'
servers:
- url: https://api.retellai.com
security:
- api_key: []
tags:
- name: Voice
paths:
  /list-voices:
    get:
      operationId: listVoices
      tags:
      - Voice
      summary: List all available voices.
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Voice'
  /get-voice/{voice_id}:
    get:
      operationId: getVoice
      tags:
      - Voice
      summary: Retrieve a voice.
      parameters:
      - name: voice_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Voice'
components:
  schemas:
    Voice:
      type: object
      properties:
        voice_id:
          type: string
          example: 11labs-Adrian
        voice_name:
          type: string
        provider:
          type: string
          enum:
          - elevenlabs
          - openai
          - deepgram
          - play_ht
          - cartesia
        accent:
          type: string
        gender:
          type: string
          enum:
          - male
          - female
        age:
          type: string
        preview_audio_url:
          type: string
  securitySchemes:
    api_key:
      type: http
      scheme: bearer
      bearerFormat: apiKey
      description: 'Retell API key, sent as: Authorization: Bearer <RETELL_API_KEY>'