curl -X POST 'https://api.openai.com/v1/audio/speech' \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "example-model",
  "input": "example-input",
  "voice": "ash"
}'

# POST /audio/speech (OpenAI API)
Base URL: https://api.openai.com/v1
Auth: Authorization; OpenAI API key; required.
Request formats: application/json.
Last verified: 2026-10-20

> Create speech

## Critical Gotchas
* The Responses API is the primary interface for new text and tool workflows; Chat Completions remains a separate compatibility API.
* Audio transcription uploads use multipart form data rather than a JSON request body.

## cURL
curl -X POST 'https://api.openai.com/v1/audio/speech' \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "example-model",
  "input": "example-input",
  "voice": "ash"
}'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| model | body | string | Yes | One of the available [TTS models](https://developers.openai.com/api/docs/guid... |
| input | body | string | Yes | The text to generate audio for. The maximum length is 4096 characters. |
| voice | body | string | Yes | The voice to use when generating the audio. Supported built-in voices are `al... |
| instructions | body | string | No | Control the voice of your generated audio with additional instructions. Does... |
| response_format | body | string | No | The format to audio in. Supported formats are `mp3`, `opus`, `aac`, `flac`, `... |
| speed | body | number | No | The speed of the generated audio. Select a value from `0.25` to `4.0`. `1.0`... |
| stream_format | body | string | No | The format to stream the audio in. Supported formats are `sse` and `audio`. `... |

## Response example
"binary"

---
Need an API key? Get one at https://platform.openai.com/api-keys

POST

POST /audio/speech — OpenAI API

OpenAI API key (required); https://api.openai.com/v1

OpenAI API

Create speech

Base URL: https://api.openai.com/v1
Auth: Authorization: Bearer <OPENAI_API_KEY>
Last verified: 2026-10-20 · upstream hash matched

Actions Try in browser→

Agents: curl -H "Accept: text/markdown" this URL
→ 359 tokens · Vary: Accept

Critical gotchas

The Responses API is the primary interface for new text and tool workflows; Chat Completions remains a separate compatibility API.

Audio transcription uploads use multipart form data rather than a JSON request body.

cURL

curl -X POST 'https://api.openai.com/v1/audio/speech' \  -H "Authorization: Bearer $OPENAI_API_KEY" \  -H 'Content-Type: application/json' \  -d '{  "model": "example-model",  "input": "example-input",  "voice": "ash"}'

Parameters

Name	In	Type	Required	Description
model	body	string	Yes	One of the available [TTS models](https://developers.openai.com/api/docs/guides/text-to-speech): `tts-1`, `tts-1-hd`, `gpt-4o-mini-tts`, or `gpt-4o-mini-tts-2025-12-15`.
input	body	string	Yes	The text to generate audio for. The maximum length is 4096 characters.
instructions	body	string	No	Control the voice of your generated audio with additional instructions. Does not work with `tts-1` or `tts-1-hd`.
voice	body	string	Yes	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](https://developers.openai.com/api/docs/guides/text-to-speech#voice-options). Custom voices must be created from audio samples. Voices created from text prompts are supported only in Live.
response_format	body	string	No	The format to audio in. Supported formats are `mp3`, `opus`, `aac`, `flac`, `wav`, and `pcm`.
speed	body	number	No	The speed of the generated audio. Select a value from `0.25` to `4.0`. `1.0` is the default.
stream_format	body	string	No	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 200 OK

"binary"

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