Checked · By Ameen Ahmed
AssemblyAI alternatives
The main alternatives to AssemblyAI are Speech Revolutions, Deepgram, ElevenLabs Scribe, Soniox, Speechmatics and OpenAI. If speaker labels are why you are looking, Speech Revolutions measured the lowest diarization error rate of the five APIs we ran, AssemblyAI included; if you need live streaming or voice agents, look at Deepgram.
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 AssemblyAI alternative
- Speaker labels on meetings, interviews or calls are wrong too often.
- The cost of an audio hour with the features you need switched on.
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, including against AssemblyAI. 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. 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.
3. 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.
4. 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.
5. Speechmatics
A speech-to-text provider offering batch and real-time, in the cloud or deployed on your own infrastructure.
Strong at
- On-premises and air-gapped deployment, for audio that can't leave your network.
- A multilingual model that handles speakers switching language mid-conversation.
Consider
- Not in our benchmark runs, so we have no diarization figure to show.
6. OpenAI
Whisper and gpt-4o-transcribe for transcription; gpt-4o-transcribe-diarize for speaker labels.
Strong at
- Convenient if you already use the OpenAI API for everything else.
Consider
- Speaker labels need the separate diarize model, whose diarized output has no word-level timings.
- File uploads are capped at 25 MB.
- Not in our diarization runs.
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 AssemblyAI
- You use summarisation, topic detection or content moderation from the same API.
- You need live streaming and batch from the same provider.
Switching from AssemblyAI 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.