Transcribe a short audio file
Authorizations
Your AssemblyAI API key. Optionally prefixed with Bearer. Also accepted as the token query parameter.
Headers
Model identifier used for request routing. The canonical value is universal-3-5-pro; u3-sync-pro and u3-pro are accepted as legacy aliases.
universal-3-5-pro Query Parameters
API key alternative for clients that cannot set the Authorization header. The header wins when both are present.
Body
Raw audio bytes. Set the part's Content-Type to audio/wav for WAV files or audio/pcm for raw S16LE little-endian PCM. Compressed audio is also accepted: audio/aac, audio/mpeg (MP3), audio/mp4 (M4A), audio/ogg (Ogg/Opus), audio/flac, or audio/webm.
Optional transcription configuration.
Response
Transcription completed successfully.
Full transcript of the audio.
Per-word confidence scores, plus start/end timestamps when the request sets timestamps to true.
Overall transcript confidence (0–1).
Duration of the submitted audio in milliseconds.
Server-generated request identifier. Include this in support requests.
End-to-end server-side processing time for the request in milliseconds, covering queue wait, decoding, and inference.