Audio

Create speech

Generates audio from the input text.

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

post/audio/speech

Request body

inputstring required

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

instructionsstring

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

response_format'mp3' | 'opus' | 'aac' | 'flac' | 'wav' | 'pcm'

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

speednumber

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

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.

Example request

{
  "voice": {
    "id": "voice_1234"
  }
}

Response

Changes

Changed in 11 of the 163 revisions of this API.1528

Sep 27, 2026de263316e28b6See the full diff
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  added the media type audio/opus for the response with the status
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  added the media type audio/pcm for the response with the status
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  added the media type audio/wav for the response with the status
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Sep 25, 2026d86203de41ae4See the full diff
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Sep 24, 202643d3ab82871511See the full diff
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Sep 3, 20269430b00d75b42See the full diff
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  added the optional property / to the response with the status
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Sep 3, 20265f6acbcbb9191See the full diff
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Aug 14, 20266ac2618eefd71See the full diff
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May 13, 202674cbcf73838f14See the full diff
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  removed subschema #1 subschema #2 from the request property anyOf list
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  added the new gpt-4o-mini-tts-2025-12-15 enum value to the request property /
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  added the media type text/event-stream for the response with the status
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This revision also has 40 changes that name no endpoint, such as unreferenced schemas being removed. See the revision's changelog
Mar 22, 202541844462b873103See the full diff
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  removed the enum value alloy of the request property
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  the request property type changed from string to no type
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  added the new optional request property
  new-optional-request-property
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  added subschema #1 subschema #2 to the request property anyOf list
  request-property-any-of-added
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  added the new gpt-4o-mini-tts enum value to the request property /
  request-property-enum-value-added
Jan 21, 202547138a7dd8b93See the full diff
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  added the new ash enum value to the request property
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  added the new coral enum value to the request property
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  added the new sage enum value to the request property
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Jan 21, 20250d83ef8a5f653See the full diff
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  removed the enum value ash of the request property
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  removed the enum value coral of the request property
  request-property-enum-value-removed
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  removed the enum value sage of the request property
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Full history (11 revisions)