Real-time Speech Recognition with AssemblyAI

Building responsive voice applications has never been more accessible. With AssemblyAI's Universal-Streaming model, you can create real-time speech recognition systems that deliver immutable transcripts in ~300ms, making it perfect for voice agents, live captioning, and interactive applications.

Why Universal-Streaming changes the game

Traditional streaming speech-to-text models force developers to choose between speed and reliability. Universal-Streaming eliminates this tradeoff with immutable transcripts that arrive in ~300ms—41% faster median latency than competing solutions like Deepgram Nova-3.

Key Advantages:

• Immutable Transcripts: Text that's already produced won't be overwritten in future responses
• Ultra-Low Latency: ~300ms word emission enables real-time agent processing
• Intelligent Endpointing: Combines acoustic and semantic features for accurate turn detection
• Transparent Pricing: Just $0.15/hour based on session duration, not audio length
• Unlimited Concurrency: Scale from 5 to 50,000+ streams without performance degradation

Video tutorial: Real-time speech recognition with AssemblyAI and Streamlit

In this video, we will see how to create this script on Python with the help of pyaudio, web sockets and asynchronous functions. The app will have the power to listen to audio input through a microphone and display the transcription in real-time. We will integrate this code into a simple Streamlit application to showcase the real-time Speech Recognition with a touch of interactivity.

Watch here:

‍Real-time speech recognition use cases and applications

1. Voice agents and AI assistants

Universal-Streaming's immutable transcripts and intelligent endpointing make it perfect for voice agents:

• Customer service bots that need immediate response capability
• Virtual assistants with natural conversation flow
• Phone system integrations for automated call handling

2. Live meeting intelligence

Transform meetings with real-time transcription and analysis:

• Real-time note-taking during video conferences
• Action item extraction as conversations happen
• Speaker identification for multi-participant meetings

3. Accessibility applications

Provide inclusive experiences with live captioning:

• Educational platforms with real-time lecture transcription
• Conference streaming with live captions
• Customer support with hearing accessibility features

Performance optimization tips

1. Audio quality matters

• Use a sample rate of at least 16kHz for optimal accuracy
• Ensure clear audio input with minimal background noise
• Consider noise reduction preprocessing for challenging environments

2. Connection management

• Keep WebSocket connections open during entire sessions to avoid reconnection overhead
• Implement proper error handling with automatic reconnection logic
• Use temporary authentication tokens for client-side implementations

3. Latency optimization

• Use unformatted transcripts for the fastest response times
• Configure end-of-turn detection based on your specific use case
• Process immutable transcripts immediately since they won't change

Pricing and scale considerations

Universal-Streaming offers transparent, predictable pricing:

• $0.15/hour based on total session duration
• No audio duration limits or pre-purchased capacity requirements
• Unlimited concurrent streams with consistent performance
• Volume discounts available for enterprise implementations

Cost optimization strategies

1. Strategic session management: Open streams only when needed
2. Session duration optimization: Close idle connections promptly
3. Batch processing: Group related audio processing tasks

Next steps

Universal-Streaming represents the cutting edge of speech recognition technology, designed specifically for the demands of modern voice applications. With immutable transcripts, intelligent endpointing, and transparent pricing, you have everything needed to build exceptional voice experiences.

Ready to get started? Sign up for your free AssemblyAI account and begin building with Universal-Streaming today.

For more advanced examples and use cases, check out our API documentation and developer cookbook.