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xai/tts/v1

Generate speech with expressive and realistic voices from xAI
Inference
Commercial use
Streaming
Partner
Schema
LLMs
PlaygroundAPI

Table of contents

About

Convert text to speech using xAI's TTS API.

Supports 5 expressive voices, inline speech tags for fine-grained delivery control, and output formats from high-fidelity MP3 to telephony-optimized μ-law.

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("xai/tts/v1", {
  input: {
    text: "Hello! This is xAI text to speech, brought to you by Fal AI."
  },
  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);

Streaming#

This model supports streaming requests. You can stream data directly to the model and get the result in real-time.

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

const stream = await fal.stream("xai/tts/v1", {
  input: {
    text: "Hello! This is xAI text to speech, brought to you by Fal AI."
  }
});

for await (const event of stream) {
  console.log(event);
}

const result = await stream.done();

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("xai/tts/v1", {
  input: {
    text: "Hello! This is xAI text to speech, brought to you by Fal AI."
  },
  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("xai/tts/v1", {
  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("xai/tts/v1", {
  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#

text string* required

The text to convert to speech. Maximum 15,000 characters. Supports speech tags for expressive delivery: inline tags like [laugh], [pause], [sigh] and wrapping tags like <whisper>text</whisper>, <slow>text</slow>.

voice VoiceEnum

Voice to use for synthesis. eve: energetic, upbeat. ara: warm, friendly. rex: confident, clear. sal: smooth, balanced. leo: authoritative, strong. Default value: "eve"

Possible enum values: eve, ara, rex, sal, leo

language LanguageEnum

BCP-47 language code or 'auto' for automatic detection. Supported: en, zh, fr, de, hi, id, it, ja, ko, pt-BR, pt-PT, ru, es-MX, es-ES, tr, vi, bn, ar-EG, ar-SA, ar-AE. Default value: "auto"

Possible enum values: auto, en, ar-EG, ar-SA, ar-AE, bn, zh, fr, de, hi, id, it, ja, ko, pt-BR, pt-PT, ru, es-MX, es-ES, tr, vi

output_format OutputFormat

Output format configuration. Defaults to MP3 at 24 kHz / 128 kbps.

{
  "text": "Hello! This is xAI text to speech, brought to you by Fal AI.",
  "voice": "eve",
  "language": "auto"
}

Output#

audio File* required

The generated audio file.

{
  "audio": {
    "url": "https://v3b.fal.media/files/b/0a92750b/exZJCm6TDejS5xIulJs2r_xai_tts_output.mp3"
  }
}

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.