Best Speech-to-Text APIs (2026)
Complete guide to STT APIs for mobile apps — accuracy, latency, pricing, and HIPAA compliance
16 min read•Tools: Whisper, Deepgram, AssemblyAI, Google STT•Updated Feb 2026
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WhisperD
DeepgramA
AssemblyAIG
Google STTQuick Recommendation
Deepgram
Best for Real-TimeChoose if you need:
- ✓You need real-time streaming with the lowest latency and best price-to-performance
- ✓Your app requires production reliability with an SLA and managed infrastructure
- ✓You want the most cost-effective managed API at $0.0043/min batch
AssemblyAI
Best for IntelligenceChoose if you need:
- ✓You need speech understanding beyond transcription: summarization, sentiment, topics
- ✓You want a single API combining STT with advanced audio intelligence
- ✓Your use case involves meeting analysis or call center transcription
Whisper
Best Open-SourceChoose if you need:
- ✓You need an open-source model for self-hosting and full data sovereignty
- ✓Your use case is batch transcription in 97+ languages
- ✓You want to fine-tune for domain-specific vocabulary
Google STT
Best for GCPChoose if you need:
- ✓You are invested in Google Cloud and need GCP integration
- ✓You need medical or legal transcription models
- ✓Your enterprise requires GCP-level compliance certifications
Side-by-Side Comparison
| Feature | Whisper | Deepgram | AssemblyAI | Google STT |
|---|---|---|---|---|
| Batch Pricing (/min) | Free self-hosted; OpenAI $0.006 | $0.0043 (Nova-3) | $0.0025 (Universal) | $0.016 (V2 standard) |
| Streaming Pricing | No native streaming | $0.0077/min | $0.0025/min | $0.016/min |
| Real-Time Latency | N/A (batch-only) | Sub-300ms (fastest) | Sub-500ms | 300-500ms |
| Language Support | 97+ languages | 36+ languages | 99 languages | 125+ languages |
| Audio Intelligence | Transcription only | Topic detection, summarization, intent | Most comprehensive: sentiment, entities, moderation | Basic; more via Vertex AI |
| Speaker Diarization | Not built-in | Built-in; real-time capable | Built-in | Built-in |
| Free Tier | Open-source (self-host free) | $200 free credits | $50 free credits | 60 min/month free |
Our Verdict
Deepgram Nova-3 is the best overall for production mobile apps: low latency, competitive accuracy, and lowest managed pricing. AssemblyAI leads when you need audio intelligence beyond transcription. Whisper is essential for offline or privacy-critical deployments.
Frequently Asked Questions
Need help choosing between Whisper and Deepgram?
Our engineers have production experience with both tools. We can help you make the right choice based on your specific requirements, timeline, and budget.