What Is Best STT Providers for Phone Calls?
Speech-to-text (STT) providers convert spoken audio into text in real-time. For phone calls, the best STT providers offer sub-200ms latency, high accuracy on telephony audio (8kHz), streaming output, and support for multiple languages. Deepgram leads in speed, AssemblyAI in accuracy features, Google in language coverage, and AWS in ecosystem integration.
How It Works
- 1
Caller's audio stream is sent to the STT provider in real-time
- 2
Provider processes audio chunks and returns transcribed text as it's generated
- 3
Streaming output enables the LLM to start processing before the caller finishes speaking
- 4
Punctuation, speaker diarization, and language detection are applied automatically
- 5
Final transcription is sent to the LLM for response generation
Key Benefits
Sub-200ms Latency
Deepgram achieves the lowest latency for real-time phone call transcription.
95%+ Accuracy
Modern neural STT models achieve near-human accuracy on telephony audio.
Streaming Output
Text is generated in real-time as the caller speaks, enabling faster AI response.
Multi-Language
Support for 30+ languages with automatic language detection per call.
Use Cases
Real-Time Voice AI
Stream transcribed text to LLM for instant response generation during live calls.
Call Transcription
Post-call transcription for compliance, analytics, and quality assurance.
Multi-Language Calls
Automatic language detection and transcription for multilingual call centers.
Speaker Diarization
Identify and separate different speakers in multi-party calls.
Frequently Asked Questions
What is the fastest STT provider for phone calls?+
Deepgram is the fastest STT provider for phone calls, achieving sub-200ms latency with streaming output. Their Nova-2 model is specifically optimized for real-time telephony transcription.
How accurate is STT for phone calls?+
Modern STT providers achieve 95%+ accuracy on clear telephony audio. Deepgram Nova-2 achieves up to 97% accuracy with proper audio quality. Background noise and accents can reduce accuracy.
Can STT handle multiple speakers?+
Yes. AssemblyAI and Deepgram both support speaker diarization, identifying and separating different speakers in real-time. This is useful for conference calls and multi-party conversations.
How does STT latency affect voice AI quality?+
STT latency directly impacts response time. Every 100ms of STT delay adds to the total round-trip time. Streaming STT enables the LLM to start processing before the caller finishes speaking, reducing perceived latency.
Use the best STT providers with QuickCallAI
Deepgram, AssemblyAI, Google Speech, and AWS Transcribe — all integrated. Free tier available.