Speech

Generate audio from text using text-to-speech models

Create speech

Generates audio from the input text.

from openai import OpenAI
from pathlib import Path

client = OpenAI()

speech_file_path = Path(__file__).parent / "speech.mp3"
response = client.audio.speech.create(
    model="tts-1",
    voice="alloy",
    input="The quick brown fox jumped over the lazy dog."
)

response.stream_to_file(speech_file_path)

Parameters

input · string · required

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

model · string · required

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

• tts-1 - Standard quality, optimized for speed
• tts-1-hd - High definition quality
• gpt-4o-mini-tts - GPT-4 optimized TTS with voice instructions support
• gpt-4o-mini-tts-2025-12-15 - Latest GPT-4 optimized TTS model

voice · string · required

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.

Previews of the voices are available in the Text to speech guide.

instructions · string

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

response_format · string · default: "mp3"

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

speed · float · default: "1.0"

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

stream_format · string

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

Response

Returns the audio file content as binary data.

Examples

Generate speech with different voices

from openai import OpenAI

client = OpenAI()

# Try different voices
voices = ["alloy", "echo", "nova"]

for voice in voices:
    response = client.audio.speech.create(
        model="tts-1",
        voice=voice,
        input="Hello! I'm an AI voice assistant."
    )
    
    response.stream_to_file(f"speech_{voice}.mp3")

Adjust speech speed

from openai import OpenAI

client = OpenAI()

response = client.audio.speech.create(
    model="tts-1",
    voice="alloy",
    input="This is a test of different speech speeds.",
    speed=1.5  # 1.5x speed
)

response.stream_to_file("speech_fast.mp3")

Use GPT-4 TTS with instructions

from openai import OpenAI

client = OpenAI()

response = client.audio.speech.create(
    model="gpt-4o-mini-tts",
    voice="alloy",
    input="Welcome to our application!",
    instructions="Speak in an enthusiastic and friendly tone"
)

response.stream_to_file("speech_custom.mp3")

Generate in different formats

from openai import OpenAI

client = OpenAI()

# Generate as WAV
response = client.audio.speech.create(
    model="tts-1",
    voice="alloy",
    input="This will be saved as a WAV file.",
    response_format="wav"
)

response.stream_to_file("speech.wav")

Async usage

import asyncio
from openai import AsyncOpenAI

async def generate_speech():
    client = AsyncOpenAI()
    
    response = await client.audio.speech.create(
        model="tts-1",
        voice="alloy",
        input="Hello from async Python!"
    )
    
    response.stream_to_file("async_speech.mp3")

asyncio.run(generate_speech())

Supported audio formats

• mp3 - MPEG audio format (default)
• opus - Opus audio format
• aac - AAC audio format
• flac - FLAC lossless audio format
• wav - Waveform audio format
• pcm - Raw PCM audio at 24kHz (16-bit signed, low-endian)

Available voices

The following voices are available for speech generation:

• alloy - Neutral and balanced
• ash - Clear and articulate
• ballad - Smooth and melodic
• coral - Warm and friendly
• echo - Resonant and clear
• fable - Expressive and storytelling
• nova - Energetic and engaging
• onyx - Deep and authoritative
• sage - Calm and measured
• shimmer - Light and cheerful
• verse - Poetic and rhythmic
• marin - Natural and conversational
• cedar - Warm and grounded

Preview audio samples for each voice in the OpenAI Text-to-Speech guide.