> ## Documentation Index > Fetch the complete documentation index at: https://docs.topcalls.ai/llms.txt > Use this file to discover all available pages before exploring further. # List built-in voices > Returns built-in voices grouped by mode and provider. These voices are available without any additional setup. Use query parameters to filter by mode, provider, language, or gender. ## OpenAPI ````yaml /api-reference/openapi.json get /v1/voices/builtin openapi: 3.0.3 info: title: TopCalls Voice API description: > TopCalls Voice Gateway API for creating and managing AI-powered phone calls. ## Authentication All API requests require authentication. Include your API key in the `Authorization` header: ``` Authorization: Bearer tc_live_xxxxx ``` ## Rate Limits Direct call creation via `POST /v1/calls` is limited to your account's `max_calls_per_minute` setting (default: 20) per minute. Exceeding it returns `429 Too Many Requests` with a `Retry-After` header. All endpoints are additionally subject to a flat limit of 120 requests per minute per account (all methods). On a `429`, wait for the number of seconds in the `Retry-After` header, then retry the same request. For automated clients, back off progressively on repeated `429`s. Limits are per account and are shared by all API keys. ## Error Format All errors follow RFC 7807 Problem+JSON format: ```json { "type": "https://api.topcalls.ai/errors/insufficient_quota", "title": "Insufficient Quota", "status": 402, "detail": "You need 5 minutes but have 3.5 remaining" } ``` version: 1.0.0 contact: name: TopCalls Support url: https://topcalls.ai license: name: Proprietary servers: - url: https://api.topcalls.ai description: Production security: [] tags: - name: Calls description: Create and manage phone calls - name: Phone Numbers description: Manage phone numbers and carriers - name: Account description: Account information and usage - name: Webhooks description: Webhook configuration and events - name: Configuration description: Available AI models, voices, and platform capabilities paths: /v1/voices/builtin: get: tags: - Configuration summary: List built-in voices description: | Returns built-in voices grouped by mode and provider. These voices are available without any additional setup. Use query parameters to filter by mode, provider, language, or gender. operationId: listBuiltinVoices parameters: - name: mode in: query description: Filter by call mode schema: type: string enum: - realtime - legacy - name: provider in: query description: Filter by voice provider schema: type: string enum: - openai - elevenlabs - deepgram - cartesia - name: language in: query description: Filter by language code (e.g., en, es, fr, de, it, ja, nl) schema: type: string - name: gender in: query description: Filter by voice gender schema: type: string enum: - male - female responses: '200': description: Built-in voices grouped by mode and provider content: application/json: schema: type: object properties: realtime: type: object properties: provider: type: string voices: type: array items: type: object properties: name: type: string description: Voice name to use in API calls description: type: string provider: type: string mode: type: string language: type: string gender: type: string default: type: string description: Default voice name legacy: type: object properties: elevenlabs: type: object properties: voices: type: array items: type: object properties: name: type: string id: type: string description: Voice ID description: type: string provider: type: string gender: type: string age: type: string default_id: type: string description: >- Default voice id (this provider uses provider-side voice ids as the default reference) note: type: string description: Provider-specific guidance for using these voices deepgram: type: object properties: voices: type: array items: type: object properties: name: type: string description: Voice name (e.g., aura-2-thalia-en) description: type: string provider: type: string language: type: string gender: type: string default: type: string note: type: string description: Provider-specific guidance for using these voices '401': $ref: '#/components/responses/Unauthorized' security: - bearerAuth: [] components: responses: Unauthorized: description: Unauthorized (missing or invalid API key) content: application/problem+json: schema: $ref: '#/components/schemas/Problem' example: status: 401 title: Unauthorized detail: Invalid or missing API key schemas: Problem: type: object required: - status - title properties: type: type: string format: uri description: Error type URI title: type: string description: Error title status: type: integer description: HTTP status code detail: type: string description: Human-readable error detail code: type: string description: > Machine-readable error code for programmatic handling. Present on errors that carry a stable identifier (e.g. `PROMPT_SAFETY_FRAUD`, `job_not_found`, `too_many_ids`, `no_matches`). Distinct from the per-field `errors[].code` used for validation failures. Scenario- specific — see each endpoint's response examples for the exact value. instance: type: string format: uuid description: Request instance ID errors: type: array description: Validation errors (for 400 responses) items: type: object properties: path: type: string description: Field path (e.g., "phone_number", "metadata.from_number") message: type: string description: Error message code: type: string description: Error code (e.g., "invalid_string", "custom") details: type: string description: Additional error details (for provider errors) securitySchemes: bearerAuth: type: http scheme: bearer description: | Use `Authorization: Bearer tc_live_xxxxx` ````