> ## Documentation Index > Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt > Use this file to discover all available pages before exploring further. # Create or add a version to a voice design > Creates a new voice design (version 1) when `voice_design_id` is omitted. When `voice_design_id` is provided, adds a new version to the existing design instead. A design can have at most 50 versions. ## OpenAPI ````yaml /openapi/voice-designs.yml post /voice_designs openapi: 3.1.0 info: title: Voice Designs API version: 2.0.0 description: Create and manage AI-generated voice designs using natural language prompts. contact: email: support@telnyx.com servers: - url: https://api.telnyx.com/v2 security: - bearerAuth: [] tags: - name: Voice Designs description: >- Create and manage AI-generated voice designs using natural language prompts. paths: /voice_designs: post: tags: - Voice Designs summary: Create or add a version to a voice design description: >- Creates a new voice design (version 1) when `voice_design_id` is omitted. When `voice_design_id` is provided, adds a new version to the existing design instead. A design can have at most 50 versions. operationId: createVoiceDesign requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/VoiceDesignRequest' responses: '201': description: Voice design created or new version added successfully. content: application/json: schema: $ref: '#/components/schemas/VoiceDesignResponse' '401': description: Unauthorized — missing or invalid bearer token. content: application/json: schema: $ref: '#/components/schemas/voice-designs_ErrorResponse' '404': description: >- Voice design not found — the specified `voice_design_id` does not exist. content: application/json: schema: $ref: '#/components/schemas/voice-designs_ErrorResponse' '409': description: Conflict — the voice design has reached the maximum of 50 versions. content: application/json: schema: $ref: '#/components/schemas/voice-designs_ErrorResponse' '422': description: Unprocessable entity — validation error in the request body. content: application/json: schema: $ref: '#/components/schemas/voice-designs_ErrorResponse' '502': description: Bad gateway — upstream voice synthesis service is unavailable. content: application/json: schema: $ref: '#/components/schemas/voice-designs_ErrorResponse' x-codeSamples: - lang: JavaScript source: |- import Telnyx from 'telnyx'; const client = new Telnyx({ apiKey: process.env['TELNYX_API_KEY'], // This is the default and can be omitted }); const voiceDesign = await client.voiceDesigns.create({ prompt: 'Speak in a warm, friendly tone', text: 'Hello, welcome to our service.', }); console.log(voiceDesign.data); - lang: Python source: |- import os from telnyx import Telnyx client = Telnyx( api_key=os.environ.get("TELNYX_API_KEY"), # This is the default and can be omitted ) voice_design = client.voice_designs.create( prompt="Speak in a warm, friendly tone", text="Hello, welcome to our service.", ) print(voice_design.data) - lang: Go source: "package main\n\nimport (\n\t\"context\"\n\t\"fmt\"\n\n\t\"github.com/team-telnyx/telnyx-go\"\n\t\"github.com/team-telnyx/telnyx-go/option\"\n)\n\nfunc main() {\n\tclient := telnyx.NewClient(\n\t\toption.WithAPIKey(\"My API Key\"),\n\t)\n\tvoiceDesign, err := client.VoiceDesigns.New(context.TODO(), telnyx.VoiceDesignNewParams{\n\t\tPrompt: \"Speak in a warm, friendly tone\",\n\t\tText: \"Hello, welcome to our service.\",\n\t})\n\tif err != nil {\n\t\tpanic(err.Error())\n\t}\n\tfmt.Printf(\"%+v\\n\", voiceDesign.Data)\n}\n" - lang: Java source: |- package com.telnyx.sdk.example; import com.telnyx.sdk.client.TelnyxClient; import com.telnyx.sdk.client.okhttp.TelnyxOkHttpClient; import com.telnyx.sdk.models.voicedesigns.VoiceDesignCreateParams; import com.telnyx.sdk.models.voicedesigns.VoiceDesignCreateResponse; public final class Main { private Main() {} public static void main(String[] args) { TelnyxClient client = TelnyxOkHttpClient.fromEnv(); VoiceDesignCreateParams params = VoiceDesignCreateParams.builder() .prompt("Speak in a warm, friendly tone") .text("Hello, welcome to our service.") .build(); VoiceDesignCreateResponse voiceDesign = client.voiceDesigns().create(params); } } - lang: Ruby source: |- require "telnyx" telnyx = Telnyx::Client.new(api_key: "My API Key") voice_design = telnyx.voice_designs.create( prompt: "Speak in a warm, friendly tone", text: "Hello, welcome to our service." ) puts(voice_design) - lang: CLI source: |- telnyx voice-designs create \ --api-key 'My API Key' \ --prompt 'Speak in a warm, friendly tone' \ --text 'Hello, welcome to our service.' components: schemas: VoiceDesignRequest: type: object description: >- Request body for creating a new voice design or adding a version to an existing one. Omit `voice_design_id` to create a new design; include it to add a new version. required: - text - prompt properties: name: type: string minLength: 1 maxLength: 255 description: >- Name for the voice design. Required when creating a new design (`voice_design_id` is not provided); ignored when adding a version. Cannot be a UUID. voice_design_id: type: string format: uuid description: >- ID of an existing voice design to add a new version to. When provided, a new version is created instead of a new design. text: type: string description: Sample text to synthesize for this voice design. prompt: type: string description: >- Natural language description of the voice style, e.g. 'Speak in a warm, friendly tone with a slight British accent'. language: type: string default: Auto description: >- Language for synthesis. Supported values: Auto, Chinese, English, Japanese, Korean, German, French, Russian, Portuguese, Spanish, Italian. Defaults to Auto. temperature: type: number format: float minimum: 0 maximum: 2 description: >- Sampling temperature controlling randomness. Higher values produce more varied output. Default: 0.9. top_k: type: integer minimum: 1 maximum: 1000 description: >- Top-k sampling parameter — limits the token vocabulary considered at each step. Default: 50. top_p: type: number format: float minimum: 0 maximum: 1 description: >- Top-p (nucleus) sampling parameter — cumulative probability cutoff for token selection. Default: 1.0. repetition_penalty: type: number format: float minimum: 1 maximum: 2 description: >- Repetition penalty to reduce repeated patterns in generated audio. Default: 1.05. max_new_tokens: type: integer minimum: 100 maximum: 4096 description: 'Maximum number of tokens to generate. Default: 2048.' provider: type: string enum: - telnyx - minimax - Telnyx - Minimax default: telnyx description: >- Voice synthesis provider. `telnyx` uses the Qwen3TTS model; `minimax` uses the Minimax speech models. Case-insensitive. Defaults to `telnyx`. example: name: friendly-narrator text: Hello, welcome to our service. prompt: Speak in a warm, friendly tone language: Auto provider: telnyx VoiceDesignResponse: type: object description: Response envelope for a single voice design with full version detail. properties: data: $ref: '#/components/schemas/VoiceDesignData' example: data: record_type: voice_design id: 550e8400-e29b-41d4-a716-446655440000 name: friendly-narrator version: 1 text: Hello, welcome. prompt: Speak in a warm tone voice_sample_size: 48000 version_created_at: '2024-01-01T00:00:00Z' created_at: '2024-01-01T00:00:00Z' updated_at: '2024-01-01T00:00:00Z' provider: Telnyx provider_supported_models: - Qwen3TTS provider_voice_id: 550e8400-e29b-41d4-a716-446655440000 voice-designs_ErrorResponse: type: object description: Standard error response envelope. properties: errors: type: array items: $ref: '#/components/schemas/ErrorObject' example: errors: - code: '10005' title: Resource not found detail: Voice design not found VoiceDesignData: type: object description: A voice design object with full version detail. properties: record_type: type: string enum: - voice_design description: Identifies the resource type. id: type: string format: uuid description: Unique identifier for the voice design. name: type: string description: Name of the voice design. version: type: integer description: Version number of this voice design. text: type: string description: Sample text used to synthesize this version. prompt: type: string description: >- Natural language prompt used to define the voice style for this version. voice_sample_size: type: integer description: Size of the voice sample audio in bytes. version_created_at: type: string format: date-time description: Timestamp when this specific version was created. created_at: type: string format: date-time description: Timestamp when the voice design was first created. updated_at: type: string format: date-time description: Timestamp when the voice design was last updated. provider: type: - string - 'null' enum: - telnyx - minimax - Telnyx - Minimax - null description: Voice synthesis provider used for this design. provider_supported_models: type: array items: type: string description: >- List of TTS model identifiers supported by this design's provider (e.g. `Qwen3TTS`, `speech-02-turbo`). provider_voice_id: type: - string - 'null' description: >- Provider-specific voice identifier. For Telnyx designs this is the design version ID; for Minimax it is the Minimax-assigned voice ID. ErrorObject: type: object description: A single error object. properties: code: type: string description: Telnyx-specific error code. title: type: string description: Short, human-readable summary of the error. detail: type: string description: Detailed, human-readable explanation of the error. source: type: object description: Reference to the source of the error. properties: pointer: type: string description: A JSON Pointer (RFC 6901) to the field that caused the error. ````