Cartesia Agents API

openapi: 3.0.3
info:
  title: Cartesia Agents API
  description: 'The Cartesia REST API for real-time voice AI - text-to-speech and voice-changer generation (single-shot bytes or Server-Sent Events), batch speech-to-text transcription, voice management and cloning, audio infill, custom datasets, pronunciation dictionaries, API keys and scoped access tokens, the Voice Agents platform (agents, calls, call batches, phone numbers, telephony providers, webhooks, deployments, knowledge base documents/folders, and evaluation metrics), and usage reporting. All requests require a `Cartesia-Version` header and an `Authorization: Bearer` API key (`sk_car_...`) or short-lived access token. The lowest-latency, streaming surface for TTS and STT is a separate WebSocket protocol documented in the companion AsyncAPI document at asyncapi/cartesia-ai-asyncapi.yml.'
  version: '2026-03-01'
  contact:
    name: Cartesia
    url: https://cartesia.ai
  license:
    name: API documentation - Cartesia Terms of Service
    url: https://cartesia.ai/terms-of-service
servers:
- url: https://api.cartesia.ai
  description: Cartesia production API
security:
- bearerAuth: []
tags:
- name: Agents
  description: Voice agent configuration and public templates.
paths:
  /agents:
    get:
      operationId: listAgents
      tags:
      - Agents
      summary: List Agents
      description: Lists all agents associated with your account.
      parameters:
      - $ref: '#/components/parameters/CartesiaVersion'
      responses:
        '200':
          description: A page of agents.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Agent'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /agents/templates:
    get:
      operationId: listAgentTemplates
      tags:
      - Agents
      summary: List Templates
      description: List of public, Cartesia-provided agent templates.
      parameters:
      - $ref: '#/components/parameters/CartesiaVersion'
      responses:
        '200':
          description: A page of agent templates.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      type: object
                      additionalProperties: true
        '401':
          $ref: '#/components/responses/Unauthorized'
  /agents/{id}:
    parameters:
    - $ref: '#/components/parameters/AgentId'
    get:
      operationId: getAgent
      tags:
      - Agents
      summary: Get Agent
      parameters:
      - $ref: '#/components/parameters/CartesiaVersion'
      responses:
        '200':
          description: The requested agent.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Agent'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
    patch:
      operationId: updateAgent
      tags:
      - Agents
      summary: Update Agent
      parameters:
      - $ref: '#/components/parameters/CartesiaVersion'
      requestBody:
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
      responses:
        '200':
          description: The updated agent.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Agent'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
    delete:
      operationId: deleteAgent
      tags:
      - Agents
      summary: Delete Agent
      parameters:
      - $ref: '#/components/parameters/CartesiaVersion'
      responses:
        '200':
          description: Deletion confirmation.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DeleteResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
  /agents/{id}/phone-numbers:
    parameters:
    - $ref: '#/components/parameters/AgentId'
    get:
      operationId: listAgentPhoneNumbers
      tags:
      - Agents
      summary: Agent Phone Numbers
      parameters:
      - $ref: '#/components/parameters/CartesiaVersion'
      responses:
        '200':
          description: Phone numbers assigned to this agent.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/PhoneNumber'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
components:
  schemas:
    PhoneNumber:
      type: object
      properties:
        id:
          type: string
        number:
          type: string
          description: E.164 phone number.
        provider_id:
          type: string
          nullable: true
        agent_id:
          type: string
          nullable: true
        created_at:
          type: string
          format: date-time
    DeleteResponse:
      type: object
      properties:
        id:
          type: string
        deleted:
          type: boolean
    Agent:
      type: object
      properties:
        id:
          type: string
        name:
          type: string
        voice_id:
          type: string
        tts_model_id:
          type: string
        stt_model:
          type: string
        system_prompt:
          type: string
        created_at:
          type: string
          format: date-time
    Error:
      type: object
      properties:
        title:
          type: string
        message:
          type: string
        error_code:
          type: string
        status_code:
          type: integer
        doc_url:
          type: string
        request_id:
          type: string
  responses:
    Unauthorized:
      description: Missing, invalid, or expired API key / access token.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: The requested resource was not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  parameters:
    AgentId:
      name: id
      in: path
      required: true
      description: The ID of the agent.
      schema:
        type: string
    CartesiaVersion:
      name: Cartesia-Version
      in: header
      required: true
      description: API version date, e.g. 2026-03-01.
      schema:
        type: string
        example: '2026-03-01'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: sk_car_... API key or short-lived access token
      description: 'Cartesia API key (sk_car_...) or a short-lived access token minted via POST /access-token, passed as Authorization: Bearer <token>. Every request also requires the Cartesia-Version header.'