# Gemini 3.1 Flash Tts API

> 인라인 스타일 제어, 30개 음성 및 최대 10명의 화자를 제공하는 Gemini 3.1 Flash 텍스트-음성 변환

최대 50000자의 `prompt`를 음성으로 변환합니다. 인라인 또는 `style_instructions`를 통해 전달 방식을 제어할 수 있습니다. 30개 음성 중 하나를 선택하고 `language_code`를 설정하거나, 다중 화자 오디오에 `speakers`(2~10명)를 사용할 수 있습니다. 출력은 mp3, wav 또는 ogg_opus이며 `temperature`는 0~2 범위입니다.

- Model id: `gemini-3.1-flash-tts`
- Made by: Google
- Category: Text to Speech
- Output: audio
- Price: $0.05 / 1000 characters (cheapest run $0.05 (50 API credits))
- Run: `POST https://api.doitong.com/v1/run/gemini-3.1-flash-tts`
- Quote: `POST https://api.doitong.com/v1/quote/gemini-3.1-flash-tts`
- Docs page: https://doitong.com/ko/developers/models/gemini-3.1-flash-tts

## Pricing

Price: **$0.05 / 1000 characters**. Billed per character of `prompt` (the price is per 1000 characters).

The full example input below costs $0.003 = 3 API credits (50 characters × 50 API credits / 1000 characters).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/gemini-3.1-flash-tts` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `prompt` |  | string | yes |  | 1 – 50000 characters | Gemini 3.1 Flash TTS용 음성 합성 텍스트입니다. 여러 화자의 줄은 'Alice: Hello!\nBob: Hi!'처럼 speakers 필드의 별칭으로 시작해야 합니다. [sigh], [laughing], [whispering], [short pause] 같은 표현형 오디오 태그나 'Say cheerfully: Have a wonderful day!' 같은 인라인 자연어 지시로 억양, 감정, 속도, 스타일을 세밀하게 제어할 수 있습니다. |
| `style_instructions` |  | string \| null | no |  | ≤ 4000 characters | 음성 콘텐츠와 분리된 상태로 유지되며 표현력, 억양, 속도, 톤, 감정을 조정하기 위해 프롬프트 앞에 삽입되는 선택적 자연어 지시입니다. 예: 'Speak warmly and slowly', 'Read this as a dramatic newscast', 'Use a British accent with a cheerful tone', 'Whisper mysteriously'. |
| `voice` |  | enum (string) | no | `Kore` | `Achernar`, `Achird`, `Algenib`, `Algieba`, `Alnilam`, `Aoede`, `Autonoe`, `Callirrhoe`, `Charon`, `Despina`, `Enceladus`, `Erinome`, `Fenrir`, `Gacrux`, `Iapetus`, `Kore`, `Laomedeia`, `Leda`, `Orus`, `Pulcherrima`, `Puck`, `Rasalgethi`, `Sadachbia`, `Sadaltager`, `Schedar`, `Sulafat`, `Umbriel`, `Vindemiatrix`, `Zephyr`, `Zubenelgenubi` | 30개의 고유 프리셋 중 단일 화자 음성을 선택합니다. speakers를 설정하면 이 선택은 비활성화됩니다. 인기 있는 여성 옵션은 강하고 단호한 전달의 Kore와 밝고 명확한 전달의 Zephyr, 따뜻하고 선율적인 전달의 Aoede입니다. 인기 있는 남성 옵션은 활기차고 경쾌한 Puck과 차분하고 전문적인 Charon입니다. |
| `language_code` |  | enum (string) \| null | no |  | `Arabic (Egypt)`, `Bangla (Bangladesh)`, `Dutch (Netherlands)`, `English (India)`, `English (US)`, `French (France)`, `German (Germany)`, `Hindi (India)`, `Indonesian (Indonesia)`, `Italian (Italy)`, `Japanese (Japan)`, `Korean (South Korea)`, `Marathi (India)`, `Polish (Poland)`, `Portuguese (Brazil)`, `Romanian (Romania)`, `Russian (Russia)`, `Spanish (Spain)`, `Tamil (India)`, `Telugu (India)`, `Thai (Thailand)`, `Turkish (Turkey)`, `Ukrainian (Ukraine)`, `Vietnamese (Vietnam)`, `Afrikaans (South Africa)`, `Albanian (Albania)`, `Amharic (Ethiopia)`, `Arabic (World)`, `Armenian (Armenia)`, `Azerbaijani (Azerbaijan)`, `Basque (Spain)`, `Belarusian (Belarus)`, `Bulgarian (Bulgaria)`, `Burmese (Myanmar)`, `Catalan (Spain)`, `Cebuano (Philippines)`, `Chinese Mandarin (China)`, `Chinese Mandarin (Taiwan)`, `Croatian (Croatia)`, `Czech (Czech Republic)`, `Danish (Denmark)`, `English (Australia)`, `English (UK)`, `Estonian (Estonia)`, `Filipino (Philippines)`, `Finnish (Finland)`, `French (Canada)`, `Galician (Spain)`, `Georgian (Georgia)`, `Greek (Greece)`, `Gujarati (India)`, `Haitian Creole (Haiti)`, `Hebrew (Israel)`, `Hungarian (Hungary)`, `Icelandic (Iceland)`, `Javanese (Java)`, `Kannada (India)`, `Konkani (India)`, `Lao (Laos)`, `Latin (Vatican City)`, `Latvian (Latvia)`, `Lithuanian (Lithuania)`, `Luxembourgish (Luxembourg)`, `Macedonian (North Macedonia)`, `Maithili (India)`, `Malagasy (Madagascar)`, `Malay (Malaysia)`, `Malayalam (India)`, `Mongolian (Mongolia)`, `Nepali (Nepal)`, `Norwegian Bokmal (Norway)`, `Norwegian Nynorsk (Norway)`, `Odia (India)`, `Pashto (Afghanistan)`, `Persian (Iran)`, `Portuguese (Portugal)`, `Punjabi (India)`, `Serbian (Serbia)`, `Sindhi (India)`, `Sinhala (Sri Lanka)`, `Slovak (Slovakia)`, `Slovenian (Slovenia)`, `Spanish (Latin America)`, `Spanish (Mexico)`, `Swahili (Kenya)`, `Swedish (Sweden)`, `Urdu (Pakistan)` | 다국어 합성 언어 재정의입니다. 언어를 지정하지 않으면 텍스트에서 자동으로 감지하고, 지정하면 모델의 음성 언어를 유도합니다. |
| `speakers` |  | array of object {voice, speaker_id} \| array of any \| null | no |  |  | 여러 화자가 텍스트의 서로 다른 부분을 읽도록 하는 음성 구성입니다. 각 화자에 음성과 해당 프롬프트 접두사에 맞는 speaker_id 별칭을 할당합니다. |
| `temperature` |  | number | no | `1` | 0 – 2 | 낮은 설정에서는 집중되고 예측 가능한 전달, 높은 설정에서는 창의적이고 다양한 전달이 되도록 조정하는 음성 무작위성 설정입니다. |
| `output_format` |  | enum (string) | no | `mp3` | `wav`, `mp3`, `ogg_opus` | 출력 오디오 형식입니다. mp3는 압축된 작은 파일을 제공하므로 권장되며, wav는 24 kHz, 16비트 모노 오디오를 WAV 컨테이너에 담은 비압축 PCM을 포함하고, ogg_opus는 Ogg 안에 Opus를 사용해 품질과 크기의 균형이 좋습니다. |

## Example input

Required parameters only:

```json
{
  "prompt": "Hello from Doitong. This is a short test sentence."
}
```

A fuller example:

```json
{
  "prompt": "Hello from Doitong. This is a short test sentence."
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/gemini-3.1-flash-tts?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Hello from Doitong. This is a short test sentence."
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.com/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/gemini-3.1-flash-tts?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "prompt": "Hello from Doitong. This is a short test sentence."
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.com/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "prompt": "Hello from Doitong. This is a short test sentence.",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/gemini-3.1-flash-tts", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.com/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "gemini-3.1-flash-tts",
      "input": {
        "prompt": "Hello from Doitong. This is a short test sentence."
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "gemini-3.1-flash-tts",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 3,
    "usd": "0.003",
    "charged": 3,
    "refunded": 0
  },
  "input": {
    "prompt": "Hello from Doitong. This is a short test sentence."
  },
  "output": {
    "audio": {
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp3",
      "content_type": "audio/mpeg",
      "file_name": "0-output.mp3",
      "file_size": 1843200
    }
  },
  "outputs": [
    {
      "type": "audio",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp3",
      "content_type": "audio/mpeg",
      "file_size": 1843200,
      "duration": 12,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `audio` | object {url, content_type, file_name, file_size} | 생성으로 만들어진 오디오 파일입니다. |

## Related models

- [Eleven v4 Text to Speech](https://doitong.com/developers/models/elevenlabs/tts/eleven-v4.md) (`elevenlabs/tts/eleven-v4`): $0.08 / 1000 characters
- [MiniMax Speech 2.8 HD](https://doitong.com/developers/models/minimax/speech-2.8-hd.md) (`minimax/speech-2.8-hd`): $0.10 / 1000 characters
- [Gemini 3.8 Flash Lite TTS](https://doitong.com/developers/models/google/gemini-3.8-flash-lite-tts.md) (`google/gemini-3.8-flash-lite-tts`): $0.111 / run
- [Gemini 3.8 Flash TTS](https://doitong.com/developers/models/google/gemini-3.8-flash-tts.md) (`google/gemini-3.8-flash-tts`): $0.045 / run
- [Gemini TTS](https://doitong.com/developers/models/gemini-tts.md) (`gemini-tts`): $0.03 / run
- [Async Text to Speech Pro V1.0](https://doitong.com/developers/models/async/tts-pro/v1.0.md) (`async/tts-pro/v1.0`): $0.01 / 1000 characters
- [Bytedance Seed Speech Text to Speech](https://doitong.com/developers/models/bytedance/seed-speech/tts/v2.md) (`bytedance/seed-speech/tts/v2`): $0.03 / 1000 characters
- [Chatterbox · Speech to Speech](https://doitong.com/developers/models/chatterbox/speech-to-speech.md) (`chatterbox/speech-to-speech`): $0.015 / minute of input audio

## Links

- HTML page: https://doitong.com/developers/models/gemini-3.1-flash-tts
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=gemini-3.1-flash-tts
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/gemini-3.1-flash-tts