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# StepAudio 3 TTS

> Human-level speech synthesis across six languages, with 12 system voices, natural-language delivery direction, and streaming playback.

![StepAudio 3 TTS](https://media.empiriolabs.ai/model-logos/stepaudio-3-tts.png)

[StepFun](/providers/stepfun) · Audio Generation

`POST /v1/audio/speech`

Human-level speech synthesis across six languages, with 12 system voices, natural-language delivery direction, and streaming playback.

## At a glance

| Field               | Value                                                       |
| ------------------- | ----------------------------------------------------------- |
| Model id            | `stepaudio-3-tts`                                           |
| Model release date  | 2026-09-09                                                  |
| Input modalities    | Text                                                        |
| Output modalities   | Audio                                                       |
| Context window      | -                                                           |
| Weight precision    | -                                                           |
| Region              | International                                               |
| Features            | text_to_speech, contextual_tts, voice_control, multilingual |
| Native inference    | No                                                          |
| New                 | Yes                                                         |
| Supported endpoints | `POST /v1/audio/speech`, `POST /v1/audio/speech:stream`     |
| Alternate model ids | `stepfun/stepaudio-3-tts`                                   |

## Pricing

| Charge    | Spec                  | Rate   |
| --------- | --------------------- | ------ |
| Synthesis | per 10,000 characters | \$0.36 |

## Example request

```bash
curl https://api.empiriolabs.ai/v1/audio/speech \
  -H 'Authorization: Bearer $EMPIRIOLABS_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"model": "stepaudio-3-tts", "input": "Hello from EmpirioLabs."}'
```

## Parameters

| Parameter           | Type    | Required | Default         | Description                                                                                                                                                                                                                                                                                                |
| ------------------- | ------- | -------- | --------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `input`             | string  | yes      | -               | Text to synthesize. Maximum 1,000 characters. Content in parentheses is treated as delivery direction and is not spoken. · Max: 1000                                                                                                                                                                       |
| `voice`             | enum    | no       | `"lively-girl"` | Official StepFun voice. Custom cloned voice IDs are also accepted via the API. · Allowed: `lively-girl`, `vibrant-youth`, `soft-spoken-gentleman`, `magnetic-voiced-male`, `elegantgentle-female`, `livelybreezy-female`, `zixinnansheng`, `Alfie`, `Ethan`, `Matthew`, `qingshunvsheng`, `tianrunnvsheng` |
| `instruction`       | string  | no       | -               | Global emotion or style guidance for the whole passage, in natural language. Maximum 500 characters. · Max: 500                                                                                                                                                                                            |
| `speed`             | number  | no       | `1`             | Speech speed. · Range: 0.5 – 2                                                                                                                                                                                                                                                                             |
| `volume`            | number  | no       | `1`             | Output volume. · Range: 0.1 – 2                                                                                                                                                                                                                                                                            |
| `language`          | enum    | no       | `"en"`          | Target language. Japanese, Korean, French, and Spanish are in preview. · Allowed: `en`, `zh`, `ja`, `ko`, `fr`, `es`                                                                                                                                                                                       |
| `response_format`   | enum    | no       | `"mp3"`         | Output audio format. · Allowed: `mp3`, `wav`, `flac`, `opus`, `pcm`                                                                                                                                                                                                                                        |
| `sample_rate`       | enum    | no       | `24000`         | Output sample rate in Hz. · Allowed: `8000`, `16000`, `22050`, `24000`                                                                                                                                                                                                                                     |
| `markdown_filter`   | boolean | no       | false           | Strip Markdown syntax from the input before it is spoken.                                                                                                                                                                                                                                                  |
| `pronunciation_map` | string  | no       | -               | Optional pronunciation overrides, as an object with a tone array of "written/spoken" rules.                                                                                                                                                                                                                |

## Notes

Maximum input is 1,000 characters. Content in parentheses is treated as delivery direction and is not spoken. Use instruction for global emotion or style guidance, up to 500 characters. Twelve system voices are available, and a custom cloned voice ID is also accepted. Recognized languages are Chinese, English, Japanese, Korean, French, and Spanish, with languages other than Chinese and English in preview. Output formats are mp3, wav, flac, opus, and pcm at 8000, 16000, 22050, or 24000 Hz. Wav is returned as a complete file rather than streamed. This model does not support voice_label.

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*Machine-readable schema:* `GET https://api.empiriolabs.ai/v1/models/stepaudio-3-tts`.