The Speechmatics API is the company's core speech-to-text service, providing batch file transcription and real-time streaming transcription via WebSocket. Powered by the Ursa 2 model (released October 2024), it supports 55+ languages and dialects, speaker diarization, automatic translation into 30+ target languages, and a suite of Voice Intelligence add-ons. Transcription requires no model fine-tuning; custom dictionaries of up to 1,000 words take effect immediately.
| General | |
|---|---|
| Release date | Generally available; Ursa 2 model released Oct 2024 |
| Developer | Speechmatics |
| Type | Cloud speech-to-text API (batch and real-time) |
| License | Commercial API |
| Documentation | docs.speechmatics.com/speech-to-text |
| GitHub | speechmatics/speechmatics-python-sdk |
Core Features
- 55+ languages and dialects: broad multilingual support including accent and dialect variants.
- Two accuracy tiers: Enhanced (optimized for accuracy) and Standard (optimized for speed and cost).
- Speaker diarization: multi-speaker detection included at no extra cost in all plans.
- Custom dictionary: up to 1,000 domain-specific words added without retraining.
- Automatic translation: transcripts translated into 30+ target languages via AI.
- Voice Intelligence add-ons: summarization, sentiment analysis, topic detection, chapter generation, and entity recognition.
- Audio events detection: identifies non-speech events in audio.
- Smart formatting: formats numbers, dates, currencies, and capitalization automatically.
- Sub-1-second real-time latency: streaming transcription via WebSocket.
- Flexible deployment: cloud API, on-premises, on-device, Docker, and Kubernetes.
Accuracy Benchmarks (Ursa 2)
| Metric | Result |
|---|---|
| WER on Kincaid46 (English) | 7.88% (surpasses human-level on that test) |
| WER improvement vs. previous Ursa | 18% reduction across 50+ languages |
| FLEURS dataset leadership | Leads in 62% of supported languages |
| Head-to-head vs. other providers | Wins 88% of comparisons |
Pricing
| Tier | Included | Rate |
|---|---|---|
| Free | 480 minutes/month | No credit card required |
| Pro | Up to 6,000 hours/month | From $0.24/hour (with discount) |
| Enterprise | Unlimited scale, no rate limits | Custom |
Volume discounts apply automatically above 500 hours per month per transcription type.
Tools and Resources
- Batch API Reference: REST API for asynchronous file transcription jobs.
- Real-time API Reference: WebSocket API reference for streaming transcription.
- Python SDK: official SDK covering STT batch, real-time, and TTS.
- JavaScript/TypeScript SDK: official browser and Node.js SDK.
- Developer Portal: API key management and usage monitoring.
Ecosystem and Integrations
- Integrates with LiveKit, Pipecat, and Vapi for voice pipeline deployments.
- Available on Microsoft Azure Marketplace.
- Compatible with on-device and edge deployments via Docker or Kubernetes.
- Medical Model variant targets clinical transcription in English, German, Danish, and Norwegian.
Start building with the free tier (no credit card required) and explore the full API via docs.speechmatics.com.
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