# Eleven v4

> Generate expressive speech with Eleven v4 from ElevenLabs. Control delivery with audio tags, voice stability, similarity settings, and IPA pronunciation.


## Overview

- **Endpoint**: `https://fal.run/elevenlabs/tts/eleven-v4`
- **Model ID**: `elevenlabs/tts/eleven-v4`
- **Category**: text-to-speech
- **Kind**: inference
**Description**: Convert text into speech with Eleven v4 from ElevenLabs.

Choose a voice and adjust stability and similarity to shape delivery. Use audio tags such as [whispering] and IPA pronunciation enclosed in forward slashes.

Supports up to 5,000 characters per request, language selection, text normalization, an optional seed for best-effort reproducibility, and optional timestamps. Choose from MP3, PCM, Opus, mu-law, and A-law output formats.

**Tags**: audio, text-to-speech, voiceover



## Pricing

- **Price**: $0.08 per 1000 characters

For more details, see [fal.ai pricing](https://fal.ai/pricing).

## API Information

This model can be used via our HTTP API or more conveniently via our client libraries.
See the input and output schema below, as well as the usage examples.


### Input Schema

The API accepts the following input parameters:


- **`text`** (`string`, _required_):
  The text to convert to speech. Supports audio tags such as [whispering] and IPA pronunciation enclosed in forward slashes.
  - Examples: "[excited] Hello! Welcome to Eleven v4."

- **`voice`** (`string`, _optional_):
  The voice to use for speech generation Default value: `"Rachel"`
  - Default: `"Rachel"`
  - Examples: "Aria", "Roger", "Sarah", "Laura", "Charlie", "George", "Callum", "River", "Liam", "Charlotte", "Alice", "Matilda", "Will", "Jessica", "Eric", "Chris", "Brian", "Daniel", "Lily", "Bill"

- **`stability`** (`float`, _optional_):
  Voice stability. Lower values allow more expressive delivery; higher values make delivery more consistent. Default value: `0.5`
  - Default: `0.5`
  - Range: `0` to `1`

- **`similarity_boost`** (`float`, _optional_):
  How closely the output follows the reference voice. Higher values increase similarity but may reduce naturalness. Default value: `0.75`
  - Default: `0.75`
  - Range: `0` to `1`

- **`seed`** (`integer`, _optional_):
  Seed for best-effort reproducibility. Identical output is not guaranteed.
  - Range: `0` to `4294967295`

- **`language_code`** (`string`, _optional_):
  Language code (ISO 639-1) for speech generation and text normalization.

- **`output_format`** (`OutputFormatEnum`, _optional_):
  Output format of the generated audio. Formatted as codec_sample_rate_bitrate. Default value: `"mp3_44100_128"`
  - Default: `"mp3_44100_128"`
  - Options: `"mp3_22050_32"`, `"mp3_44100_32"`, `"mp3_44100_64"`, `"mp3_44100_96"`, `"mp3_44100_128"`, `"mp3_44100_192"`, `"pcm_8000"`, `"pcm_16000"`, `"pcm_22050"`, `"pcm_24000"`, `"pcm_44100"`, `"pcm_48000"`, `"ulaw_8000"`, `"alaw_8000"`, `"opus_48000_32"`, `"opus_48000_64"`, `"opus_48000_96"`, `"opus_48000_128"`, `"opus_48000_192"`

- **`apply_text_normalization`** (`ApplyTextNormalizationEnum`, _optional_):
  Whether to normalize text such as numbers and dates before generation. Default value: `"auto"`
  - Default: `"auto"`
  - Options: `"auto"`, `"on"`, `"off"`

- **`timestamps`** (`boolean`, _optional_):
  Whether to return character-level timing information with the generated audio.
  - Default: `false`



**Required Parameters Example**:

```json
{
  "text": "[excited] Hello! Welcome to Eleven v4."
}
```

**Full Example**:

```json
{
  "text": "[excited] Hello! Welcome to Eleven v4.",
  "voice": "Aria",
  "stability": 0.5,
  "similarity_boost": 0.75,
  "output_format": "mp3_44100_128",
  "apply_text_normalization": "auto"
}
```


### Output Schema

The API returns the following output format:

- **`audio`** (`File`, _required_):
  The generated audio file
  - Examples: {"url":"https://v3.fal.media/files/zebra/zJL_oRY8h5RWwjoK1w7tx_output.mp3"}

- **`timestamps`** (`list<void>`, _optional_):
  Timestamps for each word in the generated speech. Only returned if `timestamps` is set to True in the request.
  - Array of void



**Example Response**:

```json
{
  "audio": {
    "url": "https://v3.fal.media/files/zebra/zJL_oRY8h5RWwjoK1w7tx_output.mp3"
  }
}
```


## Usage Examples

### cURL

```bash
curl --request POST \
  --url https://fal.run/elevenlabs/tts/eleven-v4 \
  --header "Authorization: Key $FAL_KEY" \
  --header "Content-Type: application/json" \
  --data '{
     "text": "[excited] Hello! Welcome to Eleven v4."
   }'
```

### Python

Ensure you have the Python client installed:

```bash
pip install fal-client
```

Then use the API client to make requests:

```python
import fal_client

def on_queue_update(update):
    if isinstance(update, fal_client.InProgress):
        for log in update.logs:
           print(log["message"])

result = fal_client.subscribe(
    "elevenlabs/tts/eleven-v4",
    arguments={
        "text": "[excited] Hello! Welcome to Eleven v4."
    },
    with_logs=True,
    on_queue_update=on_queue_update,
)
print(result)
```

### JavaScript

Ensure you have the JavaScript client installed:

```bash
npm install --save @fal-ai/client
```

Then use the API client to make requests:

```javascript
import { fal } from "@fal-ai/client";

const result = await fal.subscribe("elevenlabs/tts/eleven-v4", {
  input: {
    text: "[excited] Hello! Welcome to Eleven v4."
  },
  logs: true,
  onQueueUpdate: (update) => {
    if (update.status === "IN_PROGRESS") {
      update.logs.map((log) => log.message).forEach(console.log);
    }
  },
});
console.log(result.data);
console.log(result.requestId);
```


## Additional Resources

### Documentation

- [Model Playground](https://fal.ai/models/elevenlabs/tts/eleven-v4)
- [API Documentation](https://fal.ai/models/elevenlabs/tts/eleven-v4/api)
- [OpenAPI Schema](https://fal.ai/api/openapi/queue/openapi.json?endpoint_id=elevenlabs/tts/eleven-v4)

### fal.ai Platform

- [Platform Documentation](https://fal.ai/docs/documentation)
- [Python Client](https://fal.ai/docs/api-reference/client-libraries/python)
- [JavaScript Client](https://fal.ai/docs/api-reference/client-libraries/javascript)

### Other agent-readable surfaces

This file covers one model. To find anything else:

- [Platform overview](https://fal.ai/llms.txt): Entry points and representative endpoint IDs
- [Documentation index](https://fal.ai/docs/llms.txt): Every documentation page
- [Full documentation text](https://fal.ai/docs/llms-full.txt): The whole documentation inlined
- Any other model: `https://fal.ai/models/<endpoint-id>/llms.txt`