Text to speech

Text to speech#

Learn how to turn text into lifelike spoken audio.

The Audio API provides a speech endpoint based on our GPT-4o mini TTS (text-to-speech) model. It comes with 11 built-in voices and can be used to:

  • Narrate a written blog post

  • Produce spoken audio in multiple languages

  • Give realtime audio output using streaming

Here is an example of alloy:

Our usage policies require you to provide a clear disclosure to end users that the TTS voice they are hearing is AI-generated and not a human voice.

Quickstart#

The speech endpoint takes three key inputs:

  1. The model you’re using

  2. The text to be turned into audio

  3. The voice that will speak the output

Here’s a simple request example:

Generate spoken audio from input text

from pathlib import Path
from openai import OpenAI

client = OpenAI()
speech_file_path = Path(__file__).parent / "speech.mp3"

with client.audio.speech.with_streaming_response.create(
    model="gpt-4o-mini-tts",
    voice="coral",
    input="Today is a wonderful day to build something people love!",
    instructions="Speak in a cheerful and positive tone.",
) as response:
    response.stream_to_file(speech_file_path)

By default, the endpoint outputs an MP3 of the spoken audio, but you can configure it to output any supported format.

Text-to-speech models#

For intelligent realtime applications, use the gpt-4o-mini-tts model, our newest and most reliable text-to-speech model. You can prompt the model to control aspects of speech, including:

  • Accent

  • Emotional range

  • Intonation

  • Impressions

  • Speed of speech

  • Tone

  • Whispering

Our other text-to-speech models are tts-1 and tts-1-hd. The tts-1 model provides lower latency, but at a lower quality than the tts-1-hd model.

Voice options#

The TTS endpoint provides 11 built‑in voices to control how speech is rendered from text. Hear and play with these voices in OpenAI.fm, our interactive demo for trying the latest text-to-speech model in the OpenAI API. Voices are currently optimized for English.

  • alloy

  • ash

  • ballad

  • coral

  • echo

  • fable

  • nova

  • onyx

  • sage

  • shimmer

Streaming realtime audio#

The Speech API provides support for realtime audio streaming using chunk transfer encoding. This means the audio can be played before the full file is generated and made accessible.

Stream spoken audio from input text directly to your speakers

import asyncio

from openai import AsyncOpenAI
from openai.helpers import LocalAudioPlayer

openai = AsyncOpenAI()

async def main() -> None:
    async with openai.audio.speech.with_streaming_response.create(
        model="gpt-4o-mini-tts",
        voice="coral",
        input="Today is a wonderful day to build something people love!",
        instructions="Speak in a cheerful and positive tone.",
        response_format="pcm",
    ) as response:
        await LocalAudioPlayer().play(response)

if __name__ == "__main__":
    asyncio.run(main())

For the fastest response times, we recommend using wav or pcm as the response format.

Supported output formats#

The default response format is mp3, but other formats like opus and wav are available.

  • MP3: The default response format for general use cases.

  • Opus: For internet streaming and communication, low latency.

  • AAC: For digital audio compression, preferred by YouTube, Android, iOS.

  • FLAC: For lossless audio compression, favored by audio enthusiasts for archiving.

  • WAV: Uncompressed WAV audio, suitable for low-latency applications to avoid decoding overhead.

  • PCM: Similar to WAV but contains the raw samples in 24kHz (16-bit signed, low-endian), without the header.

Supported languages#

The TTS model generally follows the Whisper model in terms of language support. Whisper supports the following languages and performs well, despite voices being optimized for English:

Afrikaans, Arabic, Armenian, Azerbaijani, Belarusian, Bosnian, Bulgarian, Catalan, Chinese, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, Galician, German, Greek, Hebrew, Hindi, Hungarian, Icelandic, Indonesian, Italian, Japanese, Kannada, Kazakh, Korean, Latvian, Lithuanian, Macedonian, Malay, Marathi, Maori, Nepali, Norwegian, Persian, Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swahili, Swedish, Tagalog, Tamil, Thai, Turkish, Ukrainian, Urdu, Vietnamese, and Welsh.

You can generate spoken audio in these languages by providing input text in the language of your choice.

Customization and ownership#

Custom voices#

We do not support custom voices or creating a copy of your own voice.

Who owns the output?#

As with all outputs from our API, the person who created them owns the output. You are still required to inform end users that they are hearing audio generated by AI and not a real person talking to them.

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