AssemblyAI vs Rev — speech-to-text API comparison
AssemblyAI vs Rev (Rev AI): two cloud speech-to-text APIs compared on accuracy, diarization, languages, pricing and features for developers.
| Attribute | AssemblyAI | Rev (Rev AI) |
|---|---|---|
| Overall score | 6.4 | 5.8 |
| Deployment | cloud | cloud |
| Open source | No | No |
| Diarization | Yes | Yes |
| Languages | 99 | 58 |
| Accuracy (WER) | ~4% | ~5% |
| Pricing | $50 free credit; pay-as-you-go from ~$0.15-0.37/hr; Enterprise custom | API $0.003/min (Reverb); Essentials ~$25/seat/mo; human transcription $1.99/min |
| Compliance | SOC2, HIPAA, GDPR | SOC2, HIPAA |
| API | REST, SDK | REST, SDK |
| Best for | developers, api, rag/agents | developers, api, captioning |
AssemblyAI and Rev are both developer-focused cloud speech-to-text APIs with speaker diarization included. They’re a close match on accuracy; the differences are in features, pricing model and language breadth.
Choose Rev for the cheapest async transcription API, or when you also want optional human transcription. Choose AssemblyAI for the broadest language coverage and its LLM layer (LeMUR) for summaries and Q&A on top of the transcript.
Both are cloud-only, so neither suits audio that must stay on your own infrastructure — for that, see the best on-prem transcription ranking.