---
title: Gemini 3.1 Flash TTS
image: https://developers.cloudflare.com/og-docs.png
---

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# Gemini 3.1 Flash TTS

Text-to-Speech • Google

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`google/gemini-3.1-flash-tts`

* Third-party
* Zero data retention

| Model Info          |                                                                                                                               |
| ------------------- | ----------------------------------------------------------------------------------------------------------------------------- |
| Zero data retention | Yes                                                                                                                           |
| Pricing             | [View pricing in the Cloudflare dashboard ↗](https://dash.cloudflare.com/?to=/:account/ai/models/google/gemini-3.1-flash-tts) |

## Usage

```ts
const response = await env.AI.run(
  'google/gemini-3.1-flash-tts',
  { text: 'Hello, welcome to Cloudflare AI Gateway!' },
)
console.log(response)
```

```bash
curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "google/gemini-3.1-flash-tts",
  "input": {
    "text": "Hello, welcome to Cloudflare AI Gateway!"
  }
}'
```

```json
{
  "audio": "data:audio/l16;base64,...",
  "gatewayMetadata": {
    "keySource": "Unified"
  }
}
```

## Examples

**Custom Voice** — Generate speech with a specific voice

```ts
const response = await env.AI.run(
  'google/gemini-3.1-flash-tts',
  { text: 'The quick brown fox jumps over the lazy dog.', voice: 'Puck' },
)
console.log(response)
```

```bash
curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "google/gemini-3.1-flash-tts",
  "input": {
    "text": "The quick brown fox jumps over the lazy dog.",
    "voice": "Puck"
  }
}'
```

```json
{
  "audio": "data:audio/l16;base64,...",
  "gatewayMetadata": {
    "keySource": "Unified"
  }
}
```

**Longer Text** — Convert longer text to speech

```ts
const response = await env.AI.run(
  'google/gemini-3.1-flash-tts',
  {
    text: 'Artificial intelligence has transformed the way we interact with technology. From voice assistants to autonomous vehicles, AI is reshaping our daily lives and creating new possibilities for innovation.',
    voice: 'Charon',
  },
)
console.log(response)
```

```bash
curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "google/gemini-3.1-flash-tts",
  "input": {
    "text": "Artificial intelligence has transformed the way we interact with technology. From voice assistants to autonomous vehicles, AI is reshaping our daily lives and creating new possibilities for innovation.",
    "voice": "Charon"
  }
}'
```

```json
{
  "audio": "data:audio/l16;base64,...",
  "gatewayMetadata": {
    "keySource": "Unified"
  }
}
```

**Narrative Voice** — Generate speech with a narrative voice style

```ts
const response = await env.AI.run(
  'google/gemini-3.1-flash-tts',
  {
    text: 'Once upon a time, in a kingdom far away, there lived a brave knight who sought to protect the realm from all dangers.',
    voice: 'Kore',
  },
)
console.log(response)
```

```bash
curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "google/gemini-3.1-flash-tts",
  "input": {
    "text": "Once upon a time, in a kingdom far away, there lived a brave knight who sought to protect the realm from all dangers.",
    "voice": "Kore"
  }
}'
```

```json
{
  "audio": "data:audio/l16;base64,...",
  "gatewayMetadata": {
    "keySource": "Unified"
  }
}
```

## Parameters

text

`string`requiredmaxLength: 10000The text to convert to speech. Maximum 10,000 characters.

voice

`string`enum: Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callirrhoe, Autonoe, Enceladus, Iapetus, Umbriel, Algieba, Despina, Erinome, Algenib, Rasalgethi, Laomedeia, Achernar, Alnilam, Schedar, Gacrux, Pulcherrima, Achird, Zubenelgenubi, Vindemiatrix, Sadachbia, Sadaltager, SulafatThe voice to use for speech synthesis

temperature

`number`minimum: 0maximum: 2Controls randomness in generation (0-2)

topP

`number`minimum: 0maximum: 1Nucleus sampling threshold (0-1). Tokens with cumulative probability up to topP are considered

topK

`integer`exclusiveMinimum: 0maximum: 9007199254740991Only sample from the top K tokens. Smaller K = more focused, larger K = more diverse

maxOutputTokens

`integer`exclusiveMinimum: 0maximum: 9007199254740991Maximum number of tokens to generate

▶stopSequences\[\]

`array`Sequences where the model will stop generating further tokens

audio

`string`Base64-encoded audio data (WAV format)

## API Schemas (Raw)

Input

Output

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