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The output_format query parameter selects the audio encoding for HTTP text-to-speech requests. Non-streaming text to speech accepts mp3, wav, flac, pcm, aac, and opus. HTTP streaming text to speech accepts pcm, mp3, and wav; when omitted, streaming defaults to pcm to reduce time to first audio. Realtime text to speech over WebSocket does not accept output_format. It always streams pcm_s16le, 24000 Hz, mono, 16-bit audio as binary frames.

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Supported encodings

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Choosing a format

  • End-user playback in a browser or app: prefer mp3.
  • One-shot low-latency playback: use the HTTP streaming endpoint with the default pcm response for lower TTFA.
  • Realtime conversation: use the WebSocket realtime endpoint. The audio format is fixed to pcm_s16le, 24000 Hz, mono, 16-bit.
  • File-oriented streaming workflows: request wav or mp3.
  • Archival or post-processing: use wav or flac for lossless non-streaming output.

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Use formats with

SDK quickstart

Generate and save your first MP3 with the Python or TypeScript SDK.

Text to speech

Pass output_format on sync, async, and streaming generation requests.

Convert text to speech

See where output_format fits among the request parameters, with SDK examples.

Streaming

Use streaming-compatible formats for lower-latency playback.

Realtime text to speech

Build realtime conversation audio with fixed PCM binary frames.

CLI text to speech

Save generated audio from the command line while prototyping voices and formats.