🧠 Build a Real-Time Voice Assistant in the Browser Using LiveKit + Deepgram + OpenAI (+ Cartesia)

What if your app could talk back — like a real person?

This weekend I built a browser-based AI Voice Assistant that listens, understands, and responds — all in real time. No browser plugins, no command syntax, no install — just a mic and a modern web browser.

It’s like talking to ChatGPT — but with your voice, and without any UI friction.

🛠️ Tech Stack Overview

• 🎤 LiveKit – WebRTC-based real-time audio streaming
• ✍️ Deepgram – ASR (speech-to-text) transcription
• 🧠 OpenAI – LLM for understanding and generating replies
• 👁️ Cartesia (optional) – for visual context-aware logic (DOM/UI understanding)

⚙️ Flow Architecture
Here’s the high-level pipeline:

• A[User Speaks] --> B[LiveKit Streams Audio]
• B --> C[Deepgram Transcribes Speech]
• C --> D[OpenAI Interprets + Responds]
• D --> E[Response Returned (and Spoken)]

LiveKit handles reliable, low-latency mic audio. Deepgram transcribes voice input in real time. OpenAI then processes the transcription and generates a contextual reply. You can optionally use Web Speech API for speech synthesis — so the assistant actually “talks back.”

📦 Dev Setup
You’ll need API keys for:

• LiveKit Cloud or self-hosted server
• Deepgram API
• OpenAI Platform

And a basic setup like this:

1. Start mic capture and send audio to LiveKit room
2. Pipe LiveKit audio to Deepgram (WebSocket or media pipeline)
3. On final transcript, send to OpenAI
4. Get response → optionally use SpeechSynthesis API

I'll be open-sourcing a simple implementation soon. Let me know if you're interested and I’ll drop the repo here.

🌍 Real-World Use Cases

• AI customer support agents
• Accessibility tools for hands-free apps
• Internal smart copilots
• Voice-controlled AI tutors or dashboards
• Lightweight browser-based companions

This is a super flexible base — especially with Cartesia if you want the assistant to understand or act on what's on screen.

🧵 Docs & Links
LiveKit: https://docs.livekit.io

Deepgram: https://developers.deepgram.com/docs/quickstart

OpenAI: https://platform.openai.com/docs

Cartesia: https://cartesia.ai

ai #webdev #openai #livekit #voiceassistant #deepgram #realtimedev #webrtc #llm #hackproject