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fal-ai/lux-tts

High-quality voice cloning TTS model that generates 48kHz speech from text and a reference audio. Distilled to 4 steps for fast inference.
Inference
Commercial use
Schema
LLMs
PlaygroundAPI

Table of contents

About

Generate

1. Calling the API#

Install the client#

The client provides a convenient way to interact with the model API.

npm install --save @fal-ai/client

Setup your API Key#

Set FAL_KEY as an environment variable in your runtime.

export FAL_KEY="YOUR_API_KEY"

Submit a request#

The client API handles the API submit protocol. It will handle the request status updates and return the result when the request is completed.

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

const result = await fal.subscribe("fal-ai/lux-tts", {
  input: {
    prompt: "Hey, what's up? I'm feeling really great today! The sun is shining and there's a gentle breeze rustling through the trees.",
    audio_url: "https://storage.googleapis.com/falserverless/example_inputs/reference_audio.wav"
  },
  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);

2. Authentication#

The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.

API Key#

In case your app is running in an environment where you cannot set environment variables, you can set the API Key manually as a client configuration.
import { fal } from "@fal-ai/client";

fal.config({
  credentials: "YOUR_FAL_KEY"
});

3. Queue#

Submit a request#

The client API provides a convenient way to submit requests to the model.

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

const { request_id } = await fal.queue.submit("fal-ai/lux-tts", {
  input: {
    prompt: "Hey, what's up? I'm feeling really great today! The sun is shining and there's a gentle breeze rustling through the trees.",
    audio_url: "https://storage.googleapis.com/falserverless/example_inputs/reference_audio.wav"
  },
  webhookUrl: "https://optional.webhook.url/for/results",
});

Fetch request status#

You can fetch the status of a request to check if it is completed or still in progress.

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

const status = await fal.queue.status("fal-ai/lux-tts", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
  logs: true,
});

Get the result#

Once the request is completed, you can fetch the result. See the Output Schema for the expected result format.

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

const result = await fal.queue.result("fal-ai/lux-tts", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);

4. Files#

Some attributes in the API accept file URLs as input. Whenever that's the case you can pass your own URL or a Base64 data URI.

Data URI (base64)#

You can pass a Base64 data URI as a file input. The API will handle the file decoding for you. Keep in mind that for large files, this alternative although convenient can impact the request performance.

Hosted files (URL)#

You can also pass your own URLs as long as they are publicly accessible. Be aware that some hosts might block cross-site requests, rate-limit, or consider the request as a bot.

Uploading files#

We provide a convenient file storage that allows you to upload files and use them in your requests. You can upload files using the client API and use the returned URL in your requests.

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

const file = new File(["Hello, World!"], "hello.txt", { type: "text/plain" });
const url = await fal.storage.upload(file);

Read more about file handling in our file upload guide.

5. Schema#

Input#

prompt string* required

The text to be converted to speech.

audio_url string* required

URL of the reference audio file for voice cloning. The model will mimic the voice characteristics from this audio.

num_inference_steps integer

Number of flow-matching inference steps. 4 is recommended for best efficiency. Default value: 4

max_ref_length float

Maximum length of the reference audio to use for voice encoding, in seconds. Longer durations capture more voice characteristics but increase processing time. Default value: 5

guidance_scale float

Classifier-free guidance scale. Higher values increase adherence to the reference voice at the cost of diversity. Default value: 3

seed integer

Random seed for reproducibility.

{
  "prompt": "Hey, what's up? I'm feeling really great today! The sun is shining and there's a gentle breeze rustling through the trees.",
  "audio_url": "https://storage.googleapis.com/falserverless/example_inputs/reference_audio.wav",
  "num_inference_steps": 4,
  "max_ref_length": 5,
  "guidance_scale": 3
}

Output#

audio File* required

The generated speech audio file at 48kHz.

seed integer* required
timings Timings* required
{
  "audio": {
    "url": "",
    "content_type": "image/png",
    "file_name": "z9RV14K95DvU.png",
    "file_size": 4404019
  }
}

Other types#

File#

url string* required

The URL where the file can be downloaded from.

content_type string

The mime type of the file.

file_name string

The name of the file. It will be auto-generated if not provided.

file_size integer

The size of the file in bytes.