How to Build a Real-Time Talking Assistant with Next.js, Vercel AI SDK, and Web Speech API

Imagine asking an AI a complex question and hearing it think, pausing naturally as it formulates the next thought, and speaking the answer back to you in real-time. This isn't a sci-fi movie; it's the power of streaming text-to-speech (TTS) . In modern web development, specifically within the Next.js ecosystem, bridging the gap between Large Language Models (LLMs) and user audio perception creates a revolutionary user experience. By combining the Vercel AI SDK , React Server Components (RSC) , and the native Web Speech API , we can build a "talking assistant" that feels alive. This guide explores the architecture behind real-time audio synthesis and provides a complete, copy-pasteable code example to get you started. The Architecture: From Tokens to Audio To build a truly responsive assistant, we must abandon the "stop-and-wait" model. If we wait for the LLM to generate a full paragraph before converting it to audio, the latency ruins the immersion. Instead, we implement a streaming au