Best Speech-to-Text APIs for Voice Agents (2026)
Voice agents need real-time transcription that knows when the caller has finished speaking. Prices below are each vendor's published pay-as-you-go rates. Units differ (per minute, per hour, per token), and streaming is often billed on connection time, not speech.
Deepgram, AssemblyAI, Speechmatics, Gladia and Soniox compared on published real-time transcription pricing.
| Tool | Starting price | Best for |
|---|---|---|
| Nova-3 streaming $0.0048/min ($0.29/hr); $200 free credit | Low-latency speech-to-text for voice agents | |
| Streaming from $0.15/hr; $50 free credits | Accurate, inexpensive transcription | |
| From $0.24/hr pay as you go (as low as ~$0.12/hr with discounts) | Multilingual transcription with language switching | |
| ~$0.10/hr async; ~$0.12/hr real-time | Very low-cost speech-to-text | |
| Async from €0.16/hr; real-time €0.68/hr | Real-time multilingual transcription |
STT models compared
| Model | Price | Latency | Languages | |
|---|---|---|---|---|
| Deepgram Flux | $0.0065/min (English) | Built-in turn detection | English or multilingual | Source |
| ElevenLabs Scribe v2 Realtime | $0.39 / hr | ~150 ms partials | 90+ | Source |
| Deepgram Nova-3 | $0.0048/min streaming (monolingual, promo; reg. $0.0077) | — | 45+ (Nova models) | Source |
| AssemblyAI Universal-3.5 Pro | $0.21 / hr | Async (pre-recorded) | 18 | Source |
| OpenAI gpt-realtime-whisper | $0.017/min | Live transcription | — | Source |
| Speechmatics Linden 1 | $0.30 / hr real-time | Built-in turn detection and VAD (real-time) | 55+ | Source |
| Speechmatics Melia 1 | $0.40 / hr real-time; $0.24 / hr files | Real-time or files | 56, switches mid-sentence | Source |
| Soniox stt-rt-v5 | ~$0.12 / hr real-time; ~$0.10 / hr async | Real-time streaming | 60+ (translation included) | Source |
| Gladia Solaria-3 | €0.16 / hr async (real-time €0.68 / hr) | Async (files) | 100+ | Source |
See all voice models · Latency and prices as each vendor publishes them.
Prices from vendors' official pricing pages, checked October 14, 2026. Not sponsored; order isn't a ranking.