Checked · By Ameen Ahmed
OpenAI Whisper API alternatives
The main alternatives to OpenAI's transcription API are Speech Revolutions, AssemblyAI, Deepgram, ElevenLabs Scribe, Soniox and self-hosted WhisperX. If you need to know who said what, Speech Revolutions returns speaker labels, word timestamps and the transcript from one call, with the lowest diarization error rate of the five APIs we measured.
Every diarization figure below is measured on public datasets with the same harness and scorer. A provider we didn't test gets a description and no score.
Why teams look for an OpenAI Whisper alternative
- gpt-4o-transcribe returns text only: no speaker labels and no word timestamps.
- Speaker labels need the separate gpt-4o-transcribe-diarize model, whose diarized output has no word timings.
- Files are capped at 25 MB, so long recordings have to be split first.
Diarization, measured
Pooled diarization error rate across AMI-SDM, NotSoFar and DiPCo meeting audio, overlap-aware at a 0.25 s collar, measured 2026-07-12. Lower is better.
| Provider | Model | Pooled DER |
|---|---|---|
| Speech Revolutions | Zephyr | 16.7% |
| AssemblyAI | Universal 3.5 Pro | 24.6% |
| ElevenLabs | Scribe V2 | 29.7% |
| Deepgram | Nova-3 | 35.0% |
| Soniox | V5 | 36.2% |
Per-dataset figures, interview audio (VoxConverse) and the method: best speaker diarization API.
The options
1. Speech RevolutionsDER 16.7%
A batch speech-to-text API built around speaker diarization and word timestamps.
Strong at
- Lowest diarization error rate on every dataset we ran. See the table above.
- $0.18 an audio hour with diarization, word timestamps and keyword biasing included.
- Automatic language detection, including switching language mid-file.
- SDKs for Python, JavaScript, Go and C#, plus a migration guide that maps every field.
Consider
- Batch only: no real-time streaming.
- Transcription, diarization and timestamps only: no summarisation or other audio-intelligence features.
2. AssemblyAIDER 24.6%
A developer-focused speech-to-text API, batch first, with streaming and audio-intelligence features.
Strong at
- Streaming as well as batch transcription.
- Summarisation, topic detection and content moderation on top of the transcript.
Consider
- Second on diarization in our runs.
3. DeepgramDER 35.0%
A broad voice platform: real-time streaming, voice agents and text-to-speech alongside transcription.
Strong at
- Low-latency streaming is its core strength.
- One vendor for speech-to-text, text-to-speech and voice agents.
Consider
- Fourth of five on diarization in our runs, and weakest on DiPCo's overlapping speech.
4. ElevenLabs ScribeDER 29.7%
Speech-to-text from the voice-generation company: Scribe for files, a separate Scribe Realtime model for streaming.
Strong at
- Diarization in the file model, for up to 32 speakers.
- Same vendor as ElevenLabs text-to-speech, if you already use it.
Consider
- Third on diarization in our runs.
- Check whether the realtime model returns speaker labels before relying on it for live audio.
5. SonioxDER 36.2%
A multilingual speech-to-text API for both files and live audio.
Strong at
- One API for recorded files and live audio, across many languages.
Consider
- Last of the five on pooled diarization error in our runs.
6. WhisperX or pyannote, self-hosted
Open-source: Whisper for the words, pyannote for the speakers, run on your own GPUs.
Strong at
- No per-minute bill, and audio never leaves your infrastructure.
- Full control over models and versions.
Consider
- You run, scale and update the GPU fleet yourself.
- pyannote's models are gated on Hugging Face and need an access token.
Prices aren't listed for other providers: they are tiered and change without notice. Compare the cost of one audio hour with the features you need switched on.
When to stay with OpenAI Whisper
- Plain transcripts are all you need, and you already use the OpenAI API for everything else.
Switching from OpenAI Whisper to Speech Revolutions
The migration guide maps every request and response field side by side, in Python, JavaScript, Go and C#. Run your own files first: new accounts get $10 of credit with no card required.