This endpoint generates a TTS audio file from a given text input.
Fal.ai injects an environment variable FAL_REQUEST_ID for each request. This allows us to correlate logs belonging to a specific API call in the Fal.ai dashboard. We use "local" as a default if the variable isn't set (e.g., when running locally without fal run in a way that injects it, though fal run usually handles this). The request_id is prepended to log messages within the endpoint handlers (e.g., logger.info(f"[{request_id}] ...")).
Parameters: request: TTSInput - The input parameters for the TTS request. response: Response - The response object for the TTS request.
Returns: TTSOutput - The generated audio file and metadata.
The client provides a convenient way to interact with the model API.
npm install --save @fal-ai/clientThe @fal-ai/serverless-client package has been deprecated in favor of @fal-ai/client. Install the new package and update your imports — see client setup.
Set FAL_KEY as an environment variable in your runtime.
export FAL_KEY="YOUR_API_KEY"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("resemble-ai/chatterboxhd/text-to-speech", {
input: {},
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);The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.
import { fal } from "@fal-ai/client";
fal.config({
credentials: "YOUR_FAL_KEY"
});When running code on the client-side (e.g. in a browser, mobile app or GUI applications), make sure to not expose your FAL_KEY. Instead, use a server-side proxy to make requests to the API. For more information, check out our server-side integration guide.
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("resemble-ai/chatterboxhd/text-to-speech", {
input: {},
webhookUrl: "https://optional.webhook.url/for/results",
});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("resemble-ai/chatterboxhd/text-to-speech", {
requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
logs: true,
});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("resemble-ai/chatterboxhd/text-to-speech", {
requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);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.
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.
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.
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);The client will auto-upload the file for you if you pass a binary object (e.g. File, Data).
Read more about file handling in our file upload guide.
text stringText to synthesize into speech. Default value: "My name is Maximus Decimus Meridius, commander of the Armies of the North, General of the Felix Legions and loyal servant to the true emperor, Marcus Aurelius. Father to a murdered son, husband to a murdered wife. And I will have my vengeance, in this life or the next."
voice VoiceEnumThe voice to use for the TTS request. If neither voice nor audio are provided, a random voice will be used.
Possible enum values: Aurora, Blade, Britney, Carl, Cliff, Richard, Rico, Siobhan, Vicky
audio_url stringURL to the audio sample to use as a voice prompt for zero-shot TTS voice cloning. Providing a audio sample will override the voice setting. If neither voice nor audio_url are provided, a random voice will be used.
exaggeration floatControls emotion exaggeration. Range typically 0.25 to 2.0. Default value: 0.5
cfg floatClassifier-free guidance scale (CFG) controls the conditioning factor. Range typically 0.2 to 1.0. For expressive or dramatic speech, try lower cfg values (e.g. ~0.3) and increase exaggeration to around 0.7 or higher. If the reference speaker has a fast speaking style, lowering cfg to around 0.3 can improve pacing. Default value: 0.5
high_quality_audio booleanIf True, the generated audio will be upscaled to 48kHz. The generation of the audio will take longer, but the quality will be higher. If False, the generated audio will be 24kHz.
seed integerUseful to control the reproducibility of the generated audio. Assuming all other properties didn't change, a fixed seed should always generate the exact same audio file. Set to 0 for random seed.
temperature floatControls the randomness of generation. Range typically 0.05 to 5. Default value: 0.8
{
"text": "My name is Maximus Decimus Meridius, commander of the Armies of the North, General of the Felix Legions and loyal servant to the true emperor, Marcus Aurelius. Father to a murdered son, husband to a murdered wife. And I will have my vengeance, in this life or the next.",
"audio_url": "https://storage.googleapis.com/chatterbox-demo-samples/prompts/male_rickmorty.mp3",
"exaggeration": 0.5,
"cfg": 0.5,
"temperature": 0.8
}The generated audio file.
{
"audio": {
"url": "https://storage.googleapis.com/chatterbox-demo-samples/samples/gladiator_rick.wav"
}
}url string* requiredThe URL where the file can be downloaded from.
content_type stringThe mime type of the file.
file_name stringThe name of the file. It will be auto-generated if not provided.
file_size integerThe size of the file in bytes.
file_data stringFile data