curl --request POST \
  --url https://api.modellix.ai/api/v1/google/gemini-3.1-flash-tts \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "text": "Hello, welcome to Modellix!",
  "speakers": [
    {
      "speaker": "Narrator",
      "voice": "Kore"
    }
  ]
}
'

{
  "code": 0,
  "message": "success",
  "data": {
    "status": "pending",
    "task_id": "task-gemini-tts-001",
    "model_id": "google/gemini-3.1-flash-tts",
    "get_result": {
      "method": "GET",
      "url": "https://api.modellix.ai/api/v1/tasks/task-gemini-tts-001"
    }
  }
}

{
  "code": 400,
  "message": "Invalid parameters: parameter 'text' is required"
}

{
  "code": 401,
  "message": "Authentication failed: invalid API key"
}

{
  "code": 429,
  "message": "Rate limit exceeded: 100 requests per minute, retry after 60 seconds"
}

{
  "code": 500,
  "message": "Internal server error"
}

Gemini 3.1 Flash TTS

[Core Function] Gemini 3.1 Flash TTS is Google’s low-latency, controllable text-to-speech model. [Strengths] Single-speaker and two-speaker dialogue, 30 prebuilt voices, 70+ languages via language_code, and expressive delivery through style prompts plus inline audio tags such as [whispers], [slow], [fast], and [laughs]. Output is WAV (24 kHz mono PCM). [Best For] Voiceovers, virtual presenters, audiobook narration, multilingual speech, podcast-style scripts, and two-person dialogue. [Limitations] Do NOT use for lip-syncing existing video, music or sound-effect generation, image or audio inputs, MP3/OGG export, or API-level speed, volume, encoding, or sample-rate controls. Combined prompt and text must stay within 8,000 bytes. [Routing] Route here for controllable Gemini TTS from text only; for video with native audio use Veo; for talking-head lip sync from a portrait plus audio use Kling Avatar or SkyReels avatar models.

POST

google

gemini-3.1-flash-tts

curl --request POST \
  --url https://api.modellix.ai/api/v1/google/gemini-3.1-flash-tts \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "text": "Hello, welcome to Modellix!",
  "speakers": [
    {
      "speaker": "Narrator",
      "voice": "Kore"
    }
  ]
}
'

{
  "code": 0,
  "message": "success",
  "data": {
    "status": "pending",
    "task_id": "task-gemini-tts-001",
    "model_id": "google/gemini-3.1-flash-tts",
    "get_result": {
      "method": "GET",
      "url": "https://api.modellix.ai/api/v1/tasks/task-gemini-tts-001"
    }
  }
}

{
  "code": 400,
  "message": "Invalid parameters: parameter 'text' is required"
}

{
  "code": 401,
  "message": "Authentication failed: invalid API key"
}

{
  "code": 429,
  "message": "Rate limit exceeded: 100 requests per minute, retry after 60 seconds"
}

{
  "code": 500,
  "message": "Internal server error"
}

Authorizations

Authorization

string

header

required

Modellix API Key. Format: Bearer <your_api_key>

Body

application/json

Gemini 3.1 Flash TTS request. Always pass voice through speakers (1-2 items), even for single-speaker synthesis. When prompt is set, style and script are combined as "{prompt}: {text}". Byte limits apply to UTF-8 length (multibyte characters count toward the limit).

text

string

required

Script to be spoken. Required. Max 8,000 bytes when used alone; if prompt is set, combined "{prompt}: {text}" must not exceed 8,000 bytes. When prompt is set, put only the spoken script here (do not repeat style instructions such as "Say cheerfully:" in text). May include inline audio tags such as [whispers], [slow], [fast], [laughs], and [short pause] to steer delivery.

Required string length: 1 - 8000

Example:

"Hello, welcome to Modellix!"

speakers

object[]

required

Speaker configuration. Required. Length 1 (single voice) or 2 (dialogue). Voice is always set here; there is no top-level voice field.

Required array length: 1 - 2 elements

Show child attributes

prompt

string

Optional director or style instruction (tone, pace, emotion, scene). Max 4,000 bytes. Merged with text as "{prompt}: {text}". Combined prompt + ": " + text must not exceed 8,000 bytes. If you omit prompt, you may embed direction in text using Google's single-field pattern (e.g. "Say cheerfully: ...") or audio tags.

Maximum string length: 4000

Example:

"Friendly and warm tone"

language_code

string

Optional BCP-47 language and accent code. Examples: en-us, en-in, cmn-cn, ja-jp, ko-kr, fr-fr.

Pattern: ^[a-z]{2,3}(-[a-z0-9]+)*$

Example:

"en-us"

Response

Task submitted successfully. Poll GET /api/v1/tasks/{task_id} until the task completes; synthesized audio is returned on the task result.

code

integer

required

Response code, 0 indicates success

Example:

0

message

string

required

Response message

Example:

"success"

data

object

required

Task submission details. Poll GET /api/v1/tasks/{task_id} until status is success; audio appears in result.resources with type audio and format wav.

Show child attributes

Seedream 5 0 pro multi reference Gemini omni flash i2v

Model API

Common API

File API

Gemini 3.1 Flash TTS

Authorizations

Body

Response