# Gemini 3.8 Flash TTS

> Google Gemini 3.8 Flash TTS via Fal.AI. Expressive single-speaker narration with 30 prebuilt voices, delivery directions given as separate style instructions, and inline vocal events such as <laugh> and <sigh>. Returns WAV audio. $0.045 per 1,000 characters of spoken text.

- **Provider**: fal
- **Model ID**: google/gemini-3.8-flash-tts
- **Category**: tts_voice
- **Credits**: 105 per request
- **Pricing Type**: token_based

## API Endpoint

Base URL: https://api.core.today/v1

### Create Prediction
POST /predictions

### Get Status
GET /predictions/{job_id}

### Cancel
DELETE /predictions/{job_id}

## Authentication

Header: `X-API-Key: YOUR_API_KEY`

## Input Parameters

- `voice` (string, optional): Prebuilt voice for single-speaker speech. (Default: `Kore`; Options: `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`)
- `prompt` (string, **required**): Verbatim text to speak (billed per character). Put delivery directions in style_instructions; inline vocal events may use <laugh> or <sigh>. The provider limits the complete input to 8,192 tokens.
- `style_instructions` (string, optional): Delivery style, separate from the spoken transcript (e.g. "cheerful and friendly", "calm, slow documentary narration"). Not billed.

## Example Request

```json
{
  "model": "google/gemini-3.8-flash-tts",
  "input": {
    "voice": "Kore",
    "prompt": "Have a wonderful day!",
    "style_instructions": "cheerful and friendly"
  }
}
```

## Response Format

```json
{
  "job_id": "abc123",
  "status": "pending",
  "provider": "replicate",
  "model": "black-forest-labs/flux-schnell",
  "created_at": "2026-01-01T00:00:00Z",
  "result": null,
  "error": null
}
```

Status values: `pending`, `processing`, `completed`, `failed`, `cancelled`

## Usage Flow

1. POST /predictions with model and input → receive job_id
2. Poll GET /predictions/{job_id} until status is `completed` or `failed`
3. Result contains output URL(s) or data

## Output Type

json

## Tags

google, gemini, text-to-speech, tts, voice-synthesis, voiceover

## Documentation

https://fal.ai/models/google/gemini-3.8-flash-tts


## Token Pricing

- Input: 0.104625 credits/token
- Output: 0.104625 credits/token