Skip to main content
Hear has three transcription surfaces. Pick by when the audio exists and what the result must contain:
Hear transcription is English-only. Send language=en or omit it. Any other Hear language value returns 400 unsupported_language; use Omni for a multilingual end-to-end voice experience.

​
Transcribe one file

Use the synchronous endpoint when the file is available now and your request can wait for a text result:
Supported file types are WAV, MP3, M4A, FLAC, and OGG. This compatibility surface is best for a simple migration or a short file when you do not need a durable job, speaker labels, subtitle artifacts, or contracted word offsets.

​
Stream live speech

Use the WebSocket when a person is waiting for words to appear:
Render partial as revisable UI. Commit final as the corrected transcript. Send {"type":"commit"} when your application must force the current utterance to finish, and keep streaming silence during normal pauses so server endpointing can advance. The streaming guide contains browser capture, framing, event handling, endpointing, reconnect behavior, and a runnable example.

​
Process a finished recording

Use async jobs when you need any of these:
  • Word- or segment-level timestamps.
  • Stereo channel separation or mono diarization.
  • SRT or VTT output.
  • A result that survives the submission request.
  • Polling or a signed completion webhook.
  • Idempotent URL-based submission.
The timestamped jobs guide defines the response schema, decoded source-media timeline behavior, speaker labels, size limits, webhook signature, and retention.

​
Format final transcripts

All three surfaces support final-text presentation options:
  • numerals: digits or spoken-number form.
  • smart_format: sentence capitalization and punctuation.
  • dictation: spoken punctuation commands.
  • drop_fillers: optional filled-pause removal.
  • vocabulary: per-call phrase boost and recasing.
Formatting can change the relationship between text and word timestamps. Read Format Hear transcripts before enabling token-changing options on subtitles, legal audio, or compliance evidence.

​
Phone audio

Hear streaming accepts PCM16 or Opus. Decode an 8 kHz phone codec before sending PCM16, and do not confuse companding with resampling. The telephony audio reference gives the exact G.711 and sample-rate path.

Stream live speech

Partials, finals, endpointing, audio framing, and browser code.

Transcribe recordings

Timestamps, speakers, subtitles, jobs, and webhooks.

Format transcripts

Numerals, punctuation, dictation, fillers, and vocabulary.

Language support

The English-only Hear contract and multilingual alternatives.