Authors and ModelsStepFun

StepAudio 3 ASR Max

StepAudio 3 ASR Max
StepFun · Transcription
POST /v1/audio/transcriptions

Context-aware transcription for proper nouns, technical terms, dialects, and difficult audio including whispers, fast speech, and singing.

At a glance

FieldValue
Model idstepaudio-3-asr-max
Model release date2026-08-31
Input modalitiesAudio
Output modalitiesText
Context window-
Weight precision-
RegionInternational
Featurestranscription, speech_to_text, multilingual
Native inferenceNo
NewYes
Supported endpointsPOST /v1/audio/transcriptions
Alternate model idsstepfun/stepaudio-3-asr-max

Pricing

ChargeSpecRate
Transcriptionper hour of audio$0.24

Example request

curl https://api.empiriolabs.ai/v1/audio/transcriptions \
  -H 'Authorization: Bearer $EMPIRIOLABS_API_KEY' \
  -F model=stepaudio-3-asr-max \
  -F file=@meeting.mp3

Parameters

ParameterTypeRequiredDefaultDescription
filestringno-Audio file upload for transcription.
file_urlstringno-Public URL to an audio file.
audio_base64stringno-Base64 audio payload for JSON requests.
enable_itnbooleannotrueEnable inverse text normalization, which writes numbers, dates, and currency in their written form.
formatenumno"wav"Audio container format. · Allowed: wav, mp3, ogg, m4a, pcm
codecstringno-PCM codec such as pcm_s16le.
ratenumberno-PCM sample rate in Hz.
bitsnumberno-PCM bit depth.
channelnumberno-PCM channel count.

Notes

Supports wav, mp3, ogg, m4a, and pcm input. PCM requests should include codec, sample rate, bit depth, and channel count. The language is detected automatically and cannot be set; Chinese, English, Japanese, Korean, French, and Spanish are recognized, with languages other than Chinese and English in preview. Inverse text normalization is on by default and can be turned off with enable_itn. Hotwords and word timestamps are not available on this model. Audio is billed by its measured duration, with a one second minimum.

Machine-readable schema: GET https://api.empiriolabs.ai/v1/models/stepaudio-3-asr-max.