Gemini 3.1 Flash TTS

curl --request POST \
  --url https://api.poyo.ai/api/generate/submit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "gemini-3-1-flash-tts",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Good morning, team. [short pause] Our release is stable, and the customer demo starts in ten minutes.",
    "style_instructions": "Warm, confident product narrator with clear pacing.",
    "voice": "Kore",
    "temperature": 1,
    "output_format": "mp3"
  }
}
'

{
  "code": 200,
  "data": {
    "task_id": "task-unified-1757165031-uyujaw3d",
    "status": "not_started",
    "created_time": "2026-06-25T10:30:00"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

POST

api

generate

submit

curl --request POST \
  --url https://api.poyo.ai/api/generate/submit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "gemini-3-1-flash-tts",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Good morning, team. [short pause] Our release is stable, and the customer demo starts in ten minutes.",
    "style_instructions": "Warm, confident product narrator with clear pacing.",
    "voice": "Kore",
    "temperature": 1,
    "output_format": "mp3"
  }
}
'

{
  "code": 200,
  "data": {
    "task_id": "task-unified-1757165031-uyujaw3d",
    "status": "not_started",
    "created_time": "2026-06-25T10:30:00"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

After submission, a task_id will be returned. If you provided a callback_url, when the task status becomes finished or failed, a POST request will be sent to the callback_url.
Regardless of whether callback_url is provided, you can retrieve the result through the unified Query Task Status endpoint.

gemini-3-1-flash-tts converts text inputs into expressive speech audio using Google’s Gemini 3.1 Flash TTS model. Results are returned as task files, matching the standard image, video, 3D, and audio task response structure.

Models

gemini-3-1-flash-tts - Gemini 3.1 Flash text-to-speech generation

Required parameters

text: Text to convert to speech
- Length: 1-50000 characters
- Supports natural-language style, pace, accent, and emotional direction inline
- Supports expressive audio tags such as [sigh], [laughing], [whispering], and [short pause]
- For multi-speaker synthesis, prefix text lines with speaker aliases that match speakers[].speaker_id

Optional parameters

style_instructions: Optional style, delivery, pace, accent, tone, or emotional direction applied to the request
voice: Voice preset for single-speaker synthesis. Ignored when speakers is set. Default: Kore
language_code: Optional language enum used to steer multilingual synthesis. If omitted, the model auto-detects from text
speakers: Exactly two speaker objects for dialogue. When set, top-level voice is ignored. Each item includes:
- voice: Gemini voice preset
- speaker_id: Alias containing only letters, numbers, and underscores with no whitespace, unique within the request, used as a prefix in text
temperature: Number controlling delivery variation. Default: 1. Range: 0-2
output_format: mp3, wav, or ogg_opus. Default: mp3. Use mp3 for compact playback, wav for uncompressed post-production, and ogg_opus for quality-to-size balance

Voice Presets

Supported values: 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.

Examples

Single speaker with audio tags

{
  "model": "gemini-3-1-flash-tts",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Good morning, team. [short pause] Our release is stable, and the customer demo starts in ten minutes.",
    "style_instructions": "Warm, confident product narrator with clear pacing.",
    "voice": "Kore",
    "temperature": 1,
    "output_format": "mp3"
  }
}

Multilingual store assistant

{
  "model": "gemini-3-1-flash-tts",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "English: Your order is ready for pickup.\nSpanish: Su pedido esta listo para recoger.\nFrench: Votre commande est prete a etre retiree.",
    "style_instructions": "Friendly store assistant voice, natural and concise.",
    "voice": "Zephyr",
    "language_code": "English (US)",
    "temperature": 1,
    "output_format": "wav"
  }
}

Two speaker podcast

{
  "model": "gemini-3-1-flash-tts",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Host: Welcome back to Launch Notes. [laughing] Today's build finally passed.\nGuest: Great news. Let's keep the update clear and calm for users.",
    "style_instructions": "Conversational podcast tone with distinct speaker energy.",
    "speakers": [
      {
        "speaker_id": "Host",
        "voice": "Charon"
      },
      {
        "speaker_id": "Guest",
        "voice": "Kore"
      }
    ],
    "temperature": 1,
    "output_format": "ogg_opus"
  }
}

Notes

PoYo’s public parameter name is text.
Query status through the standard task status API.
Successful responses return files, where the generated speech uses file_type: audio.

Authorizations

Authorization

string

header

required

All API endpoints require Bearer Token authentication.

Create an API key: sign in to PoYo, open Dashboard → API Key at poyo.ai/dashboard/api-key, and click to create a key.

Add it to the request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

model

enum<string>

required

Model identifier.

Available options:

gemini-3-1-flash-tts

Example:

"gemini-3-1-flash-tts"

input

object

required

Show child attributes

callback_url

string<uri>

Webhook callback URL for result notifications

Example:

"https://your-domain.com/callback"

Response

Task submitted successfully

code

enum<integer>

required

Business status code. 200 means success; any other value means the request failed. Always check this field: some validation errors return HTTP 200 with code: 400 in the body.

200: Success
400: Invalid request parameters
401: Missing or invalid API key
402: Insufficient credits
403: Permission denied
404: Resource not found
408: Request timeout
429: Rate limit exceeded
500: Internal server error
502: Upstream service error
503: Service unavailable

See Error Codes for details.

Available options:

200,

400,

401,

402,

403,

404,

408,

429,

500,

502,

503

Example:

200

data

object

required

Show child attributes

​Models

​Required parameters

​Optional parameters

​Voice Presets

​Examples

​Single speaker with audio tags

​Multilingual store assistant

​Two speaker podcast

​Notes

Authorizations

Body

Response

Models

Required parameters

Optional parameters

Voice Presets

Examples

Single speaker with audio tags

Multilingual store assistant

Two speaker podcast

Notes