# Google Gemini 3.8 Flash TTS API

> Gemini 3.8 Flash TTS by Google turns text into expressive speech with 30 prebuilt voices and natural-language style direction.

Source: https://www.sandbase.ai/models/google/gemini-3.8-flash-tts
API reference: https://www.sandbase.ai/models/google/gemini-3.8-flash-tts/docs

## Facts

- Provider: Google
- Type: Audio model
- Model ID: `google/gemini-3.8-flash-tts`
- Price: From $0.04 per run
- Capabilities: text to speech
- Billing: pay per use from one SandBase balance; no provider account or subscription needed

## Call it

- Unified Run API: `POST https://api.sandbase.ai/v1/run`

```bash
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "google/gemini-3.8-flash-tts",
  "voice": "Kore",
  "prompt": "Have a wonderful day!",
  "style_instructions": "cheerful and friendly"
}'
```

The response returns a run id; poll `GET https://api.sandbase.ai/v1/run/{id}` until the status is `completed` or `failed`.

## FAQ

### How do I call Google Gemini 3.8 Flash TTS through SandBase?

Create a SandBase API key, then send requests with the model ID "google/gemini-3.8-flash-tts" to Unified Run API (/v1/run) at https://api.sandbase.ai. The request examples on this page show the exact payload.

### Do I need a separate Google account?

No. One SandBase API key and balance gives you access to Google Gemini 3.8 Flash TTS and the other models in the catalog; you do not need to sign up with Google separately.

## README

### Gemini 3.8 Flash TTS

Gemini 3.8 Flash TTS turns text into expressive speech with 30 prebuilt voices. Direct the delivery in plain language with `style_instructions`, such as tone, pace, or accent.

#### Fields

| Field | Type | Default | Notes |
|---|---|---|---|
| `prompt` | string, required | — | Text to speak. |
| `style_instructions` | string | — | How to say it, e.g. “warm and unhurried, slight smile”. |
| `voice` | `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` | `Kore` | Prebuilt voice. |

#### Billing

$0.045 per started 1,000 characters of text, with a one-unit minimum.

| Text | Price |
|---|---|
| 200 characters | $0.045 |
| 1,000 characters | $0.045 |
| 2,500 characters | $0.135 |

Failed runs are not charged.

#### Prompting

- Put delivery direction in `style_instructions`, not in the text itself.

#### Limits

- Single speaker per request.

#### Also on SandBase

Related: `google/gemini-3.8-flash-lite-tts` (cheaper), `google/gemini-3.1-flash-tts` (multi-speaker).