As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/stepaudio-3-asr-tts/

# StepAudio 3 ASR Max / StepAudio 3 TTS

StepFun, StepAudio 3 family. Status: current. Type: speech and audio. Released: 2026-09-15.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| StepFun API | `stepaudio-3-asr-max` |  | https://platform.stepfun.ai/docs/en/guides/models/audio |
| StepFun API | `stepaudio-3-tts` |  | https://platform.stepfun.ai/docs/en/guides/models/audio |
| StepFun API (preview) | `stepaudio-3-gen-preview` |  | https://platform.stepfun.ai/docs/en/guides/models/audio |

## Pricing

- Per hour, speech recognition: $0.40
- Per 10K characters, speech: $0.36
- Unit as published: USD: stepaudio-3-asr-max $0.40/hour of audio; stepaudio-3-tts $0.36 per 10,000 characters; voice cloning $1.50/voice
- Source: https://platform.stepfun.ai/docs/en/pricing/details
- Last checked: 2026-09-29

## Specs

- Input: audio, text
- Output: text, audio
- Context window: not published
- Max output: not published
- Open weights: no
- Licence: proprietary

## Where it stands

- Newer speech and audio models in the registry since its release: 25. The 5 newest:
  - NVIDIA Nemotron 3.5 Transcribe (30B-A4B) (2026-10-28) https://postcutoff.com/m/nemotron-3-5-transcribe/
  - Hy-SimulMT-30B-A3B (2026-10-22) https://postcutoff.com/m/hy-simulmt-30b-a3b/
  - Eleven Realtime v1 Max / Mini (2026-10-20) https://postcutoff.com/m/eleven-realtime-v1-max/
  - Voxtral Mini Transcribe 3 (+ Mini Transcribe Realtime 3) (2026-10-20) https://postcutoff.com/m/voxtral-mini-transcribe-3/
  - Voxtral Small Transcribe 3 (2026-10-20) https://postcutoff.com/m/voxtral-small-transcribe-3/
- Before it from StepFun: StepFun Step-Audio-EditX (2025-11-06) https://postcutoff.com/m/step-audio-editx/
- Closed weights; access is hosted only.

## What stands out

- #1 non-streaming ASR on AA-WER: Artificial Analysis ranked StepAudio 3 ASR #1 on its AA-WER Index for non-streaming speech-to-text with 1.7% WER (StepAudio 2.5 ASR: 4.7%). Source: https://x.com/ArtificialAnlys/status/2102485740248842710
- Context-aware streaming TTS: Natural, context-aware speech with low-latency streaming, natural-language control and voice cloning; 1,000-char input limit; wav/mp3/flac/opus/pcm. Source: https://platform.stepfun.ai/docs/en/guides/models/audio

## Notes

Family file for the non-realtime StepAudio 3 models. Languages: zh, en, ja, ko, fr, es (non-zh/en in preview). stepaudio-3-gen-preview (speech+SFX+ambience+BGM) and stepaudio-3-music-preview are free during preview. Previous gen: stepaudio-2.5-asr ($0.022/h), stepaudio-2.5-asr-stream ($0.18/h), stepaudio-2.5-tts ($0.85/10k chars). Exact per-model release date assumed = family launch 2026-09-15.

Sources: https://platform.stepfun.ai/docs/en/guides/models/audio · https://platform.stepfun.ai/docs/en/pricing/details

Model page: https://postcutoff.com/m/stepaudio-3-asr-tts/