Introducing Amazon Polly Bidirectional Streaming: Real-time speech synthesis for conversational AI
TL;DR
Amazon Polly introduces a new Bidirectional Streaming API that enables real-time TTS synthesis – sending text and receiving audio happen simultaneously.
Key Points
- Designed for conversational AI apps where LLM responses are generated incrementally and waiting for full text completion is not an option.
- The API significantly reduces perceived latency by starting audio synthesis before the complete text is available.
- Developers can build more natural voice interactions without having to implement complex buffering logic themselves.
Nauti's Take
Real-time bidirectional TTS streaming is the missing piece for natural-feeling voice AI. Polly's new API means you can start receiving speech as you're still sending text — that latency reduction is what makes voice interfaces feel actually conversational.
Context
Latency is the killer of every voice interaction – waiting for the full LLM output before audio starts produces unconvincing products. The Bidirectional Streaming API tackles exactly this bottleneck at the infrastructure level, freeing developers to focus on product logic. This is especially relevant as voice interfaces in agentic AI systems are rapidly gaining importance.
Sources
