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Audio
Speech

Create speech

client.audio.speech.create(SpeechCreateParams { input, model, voice, 4 more } body, RequestOptionsoptions?): Response
POST/audio/speech

Generates audio from the input text.

Returns the audio file content, or a stream of audio events.

ParametersExpand Collapse
body: SpeechCreateParams { input, model, voice, 4 more }
input: string

The text to generate audio for. The maximum length is 4096 characters.

maxLength4096
model: (string & {}) | SpeechModel

One of the available TTS models: tts-1, tts-1-hd, gpt-4o-mini-tts, or gpt-4o-mini-tts-2025-12-15.

One of the following:
(string & {})
SpeechModel = "tts-1" | "tts-1-hd" | "gpt-4o-mini-tts" | "gpt-4o-mini-tts-2025-12-15"
One of the following:
"tts-1"
"tts-1-hd"
"gpt-4o-mini-tts"
"gpt-4o-mini-tts-2025-12-15"
voice: string | "alloy" | "ash" | "ballad" | 7 more | ID { id }

The voice to use when generating the audio. Supported built-in voices are alloy, ash, ballad, coral, echo, fable, onyx, nova, sage, shimmer, verse, marin, and cedar. You may also provide a custom voice object with an id, for example { "id": "voice_1234" }. Previews of the voices are available in the Text to speech guide.

One of the following:
string
"alloy" | "ash" | "ballad" | 7 more
"alloy"
"ash"
"ballad"
"coral"
"echo"
"sage"
"shimmer"
"verse"
"marin"
"cedar"
ID { id }

Custom voice reference.

id: string

The custom voice ID, e.g. voice_1234.

instructions?: string

Control the voice of your generated audio with additional instructions. Does not work with tts-1 or tts-1-hd.

maxLength4096
response_format?: "mp3" | "opus" | "aac" | 3 more

The format to audio in. Supported formats are mp3, opus, aac, flac, wav, and pcm.

One of the following:
"mp3"
"opus"
"aac"
"flac"
"wav"
"pcm"
speed?: number

The speed of the generated audio. Select a value from 0.25 to 4.0. 1.0 is the default.

minimum0.25
maximum4
stream_format?: "sse" | "audio"

The format to stream the audio in. Supported formats are sse and audio. sse is not supported for tts-1 or tts-1-hd.

One of the following:
"sse"
"audio"
ReturnsExpand Collapse
unnamed_schema_1 = Response

Create speech

import fs from "fs";
import path from "path";
import OpenAI from "openai";

const openai = new OpenAI();

const speechFile = path.resolve("./speech.mp3");

async function main() {
  const mp3 = await openai.audio.speech.create({
    model: "gpt-4o-mini-tts",
    voice: "alloy",
    input: "Today is a wonderful day to build something people love!",
  });
  console.log(speechFile);
  const buffer = Buffer.from(await mp3.arrayBuffer());
  await fs.promises.writeFile(speechFile, buffer);
}
main();
Returns Examples