Qwen-Audio-TTS server-side events

task-started

After the client sends the run-task command, the server returns a task-started event to signal that the task has started. The client can send subsequent commands only after receiving this event.

{
  "header": {
    "task_id": "2bf83b9a-baeb-4fda-8d9a-xxxxxxxxxxxx",
    "event": "task-started",
    "attributes": {}
  },
  "payload": {}
}

Parameter	Type	Description
header.task_id	string	The task ID generated by the client.
header.event	string	Event type. Fixed value: `task-started`.
payload	object	Empty object.

result-generated

After the client sends text, the server continuously returns result-generated events. Each event carries sentence-level metadata.

{
  "header": {
    "task_id": "3f2d5c86-0550-45c0-801f-xxxxxxxxxx",
    "event": "result-generated",
    "attributes": {}
  },
  "payload": {
    "output": {
      "sentence": {
        "index": 0,
        "words": []
      },
      "type": "sentence-begin",
      "original_text": "Before my bed, moonlight shines bright,"
    }
  }
}

Parameter	Type	Description
header.event	string	Event type. Fixed value: `result-generated`.
payload.output	object	Output information.
payload.output.type	string	Sub-event type. Valid values: `sentence-begin`: Sentence start. Returns the text to be synthesized. `sentence-synthesis`: Marks an audio frame. One audio frame is transmitted over the WebSocket binary channel immediately after each event. `sentence-end`: Sentence end. Returns the text content and usage information (`usage`).
payload.output.sentence.index	integer	Sentence index, starting from 0.
payload.output.sentence.words	array	Word-level timestamp array.
payload.output.sentence.words.text	string	Text content of the word.
payload.output.sentence.words.begin_index	integer	Start character index of the word within the sentence. Starts at 0.
payload.output.sentence.words.end_index	integer	End character index of the word within the sentence. Starts at 1.
payload.output.sentence.words.begin_time	integer	Start time of the word's corresponding audio, in milliseconds.
payload.output.sentence.words.end_time	integer	End time of the word's corresponding audio, in milliseconds.
payload.output.original_text	string	Text of the sentence as segmented for synthesis.
payload.usage	object	Billing usage, returned in the `sentence-end` event. Note: `qwen-audio-3.1-tts-flash` is billed by input and output tokens. `qwen-audio-3.1-tts-plus`, `qwen-audio-3.0-tts-plus`, and `qwen-audio-3.0-tts-flash` are billed by character.
payload.usage.input_tokens	integer	Input token count for this request. Note: Applies to `qwen-audio-3.1-tts-plus`, `qwen-audio-3.1-tts-flash`.
payload.usage.output_tokens	integer	Output token count for this request. Note: Applies to `qwen-audio-3.1-tts-plus`, `qwen-audio-3.1-tts-flash`.
payload.usage.total_tokens	integer	Sum of input and output tokens. Note: Applies to `qwen-audio-3.1-tts-plus`, `qwen-audio-3.1-tts-flash`.
payload.usage.characters	integer	Cumulative number of billed characters.

task-finished

The server returns a task-finished event when the task completes. The client can then close the WebSocket connection or reuse it to start a new task.

{
  "header": {
    "task_id": "2bf83b9a-baeb-4fda-8d9a-xxxxxxxxxxxx",
    "event": "task-finished",
    "attributes": {
      "request_uuid": "0a9dba9e-d3a6-45a4-be6d-xxxxxxxxxxxx"
    }
  },
  "payload": {
    "usage": {
      "characters": 13
    }
  }
}

Parameter	Type	Description
header.event	string	Event type. Fixed value: `task-finished`.
payload.usage	object	The fields are the same as usage in result-generated.

task-failed

The server returns a task-failed event when the task fails. On receiving this event, the client must close the WebSocket connection and handle the error.

{
  "header": {
    "task_id": "2bf83b9a-baeb-4fda-8d9a-xxxxxxxxxxxx",
    "event": "task-failed",
    "error_code": "InvalidParameter",
    "error_message": "[tts:]Engine return error code: 418",
    "attributes": {}
  },
  "payload": {}
}

Parameter	Type	Description
header.event	string	Event type. Fixed value: `task-failed`.
header.error_code	string	Error code.
header.error_message	string	Detailed error message.

​task-started

​result-generated

​task-finished

​task-failed

task-started

result-generated

task-finished

task-failed