> ## Documentation Index > Fetch the complete documentation index at: https://docs.powertokens.ai/llms.txt > Use this file to discover all available pages before exploring further. # Text to Speech > Call Ali `qwen3-tts-instruct-flash` through the unified `/v1/audio/speech` endpoint. Response contract: - non-streaming returns the official Ali JSON response; - streaming returns `text/event-stream` and forwards Ali SSE payloads. ## OpenAPI ````yaml api-reference/en/zmodelAudio/ali/qwen3-tts-instruct-flash.json POST /v1/audio/speech openapi: 3.0.1 info: title: Ali Text-to-Speech version: 1.0.0 description: >- Ali channel text-to-speech capability for `/v1/audio/speech`. The project currently implements the official field subset for `qwen3-tts-instruct-flash` only. This document intentionally includes only the implemented official fields: `model`, `input`, `voice`, `instructions`, `optimize_instructions`, and `language_type`. Streaming follows the official Ali HTTP contract: clients must explicitly send `X-DashScope-SSE: enable` in the request header. This channel does not expose `stream_format`. Billing note: the gateway maps upstream `usage.characters` to unified `usage.prompt_tokens_details.audio_tokens`, keeps `usage.output_tokens` in `usage.completion_tokens_details.audio_tokens`, and stores both raw Ali usage and normalized usage snapshots in consume_detail for billing traceability. servers: - url: https://api.powertokens.ai description: Baze API service endpoint security: [] tags: - name: Ali Audio description: Ali text-to-speech capability paths: /v1/audio/speech: post: tags: - Ali Audio summary: Ali text-to-speech description: >- Call Ali `qwen3-tts-instruct-flash` through the unified `/v1/audio/speech` endpoint. Response contract: - non-streaming returns the official Ali JSON response; - streaming returns `text/event-stream` and forwards Ali SSE payloads. operationId: aliAudioSpeech parameters: - name: X-DashScope-SSE in: header required: false description: >- Official Ali HTTP streaming switch. Send `enable` to receive `text/event-stream`. schema: type: string enum: - enable requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AliSpeechRequest' examples: basic: summary: Non-streaming request value: model: qwen3-tts-instruct-flash input: Introduce this product with a slightly faster speaking rate. voice: Cherry instructions: Speak faster with a brighter tone. optimize_instructions: false language_type: English stream: summary: Streaming request value: model: qwen3-tts-instruct-flash input: Today is a wonderful day to build something people love. voice: Cherry language_type: English responses: '200': description: >- Successful call. Non-streaming returns the official Ali JSON response; streaming returns Ali SSE payloads. content: application/json: schema: $ref: '#/components/schemas/AliSpeechResponse' text/event-stream: schema: type: string description: >- Ali SSE event stream. Each event body can be parsed as an Ali audio response chunk. '400': description: Invalid request parameters. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - BearerAuth: [] components: schemas: AliSpeechRequest: type: object required: - model - input - voice properties: model: type: string description: 'Model name. Available options: `qwen3-tts-instruct-flash`.' enum: - qwen3-tts-instruct-flash input: type: string description: Text to synthesize. This field accepts multilingual input. voice: type: string description: Voice to use. See supported system voices. enum: - Cherry - Serena - Ethan - Chelsie - Momo - Vivian - Moon - Maia - Kai - Nofish - Bella - Eldric Sage - Mia - Mochi - Bellona - Vincent - Bunny - Neil - Elias - Arthur - Nini - Seren - Pip - Stella instructions: type: string description: >- Sets instructions. See instruction control. Default: none, no effect when not set. Maximum length: 1600 tokens. Supported languages: Chinese and English only. Scope: This feature is only supported by the qwen3-TTS-Instruct-Flash-Realtime series models. optimize_instructions: type: boolean description: >- Optimizes `instructions` semantically to improve the naturalness and expressiveness of voice synthesis. Default: `false`. Behavior: When set to `true`, the system semantically enhances and rewrites the `instructions` content to generate internal instructions better suited for voice synthesis. Recommended for high-quality, refined voice expression. Depends on the `instructions` parameter. If `instructions` is empty, this parameter has no effect. Scope: This feature is only supported by the qwen3-TTS-Instruct-Flash series models. language_type: type: string description: >- Language type for the synthesized audio. Defaults to `Auto`. - `Auto`: Suitable when the text contains multiple languages or the language is uncertain. The model automatically matches pronunciation for different language segments, but accuracy is not guaranteed. - Specified language: Suitable for single-language text. Specifying a language significantly improves synthesis quality, generally outperforming `Auto`. enum: - Auto - Chinese - English - German - Italian - Portuguese - Spanish - Japanese - Korean - French - Russian AliSpeechResponse: type: object properties: status_code: type: integer description: |- HTTP status code. Follows RFC 9110 definitions. For example: - 200: Request successful, normal response returned - 400: Client request parameter error - 401: Unauthorized access - 404: Resource not found - 500: Internal server error request_id: type: string description: >- Unique request identifier for this request, useful for troubleshooting. code: type: string description: Error code. Returned when the request fails. message: type: string description: Error message. Returned when the request fails. output: type: object description: Model output. properties: text: nullable: true description: Always null and can be ignored. finish_reason: type: string description: >- Generation status identifier. It is `null` while still generating; it becomes `stop` when the model naturally finishes or a stop condition is triggered. choices: nullable: true description: Always null and can be ignored. audio: type: object properties: data: type: string description: Base64 audio data for streaming output. url: type: string format: uri description: Full audio file URL, valid for 24 hours. id: type: string description: Unique audio identifier. expires_at: type: integer description: UNIX timestamp of the URL expiration time. usage: type: object description: >- Token or character consumption for this request. qwen-TTS returns token consumption information, while qwen3-TTS-Flash returns character consumption information. properties: input_tokens: type: integer description: >- Input token count. For `qwen3-tts-flash`, this field is fixed at 0. output_tokens: type: integer description: >- Output audio token count. For `qwen3-tts-flash`, this field is fixed at 0. total_tokens: type: integer description: Total token count. Only returned by `qwen-tts`. characters: type: integer description: Input character count. Only returned by `qwen3-tts-flash`. ErrorResponse: type: object required: - error properties: error: $ref: '#/components/schemas/ErrorObject' ErrorObject: type: object required: - message - type - param - code properties: message: type: string type: type: string param: type: string code: type: string securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: API Token description: 'Pass `Authorization: Bearer ` in the request header.' ````