> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/openai/openai-python/llms.txt
> Use this file to discover all available pages before exploring further.

# Speech

> Generate audio from text using text-to-speech models

## Create speech

Generates audio from the input text.

```python theme={null}
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

<ParamField path="input" type="string" required>
  The text to generate audio for. The maximum length is 4096 characters.
</ParamField>

<ParamField path="model" type="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
</ParamField>

<ParamField path="voice" type="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](https://platform.openai.com/docs/guides/text-to-speech#voice-options).
</ParamField>

<ParamField path="instructions" type="string">
  Control the voice of your generated audio with additional instructions. Does not work with `tts-1` or `tts-1-hd`.
</ParamField>

<ParamField path="response_format" type="string" default="mp3">
  The format to audio in. Supported formats are `mp3`, `opus`, `aac`, `flac`, `wav`, and `pcm`.
</ParamField>

<ParamField path="speed" type="float" default="1.0">
  The speed of the generated audio. Select a value from `0.25` to `4.0`. `1.0` is the default.
</ParamField>

<ParamField path="stream_format" type="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`.
</ParamField>

### Response

Returns the audio file content as binary data.

## Examples

### Generate speech with different voices

```python theme={null}
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

```python theme={null}
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

```python theme={null}
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

```python theme={null}
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

```python theme={null}
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

<Info>
  Preview audio samples for each voice in the [OpenAI Text-to-Speech guide](https://platform.openai.com/docs/guides/text-to-speech#voice-options).
</Info>