Knock

Knock is a social platform built around the idea that the best hangouts aren’t scheduled. Group calls are heavy — links, calendars, “can everyone hear me.” Knock is the opposite: see who’s around, knock, and you’re in a room together. It’s closer to leaving a door open than booking a meeting.

What I built

• Real-time audio and video over WebRTC, with a Socket.IO signalling layer to negotiate peer connections quickly and keep latency low.
• Presence and rooms — see who’s online, drop into a space, and pull friends in without a formal invite flow.
• A React front end over a Node.js backend that manages rooms, presence, and session state.

Why it matters

WebRTC is one of those technologies that looks simple in a tutorial and gets hard the moment you have more than two people, flaky networks, and devices that disagree about codecs. Getting connections to establish fast and stay stable was the core challenge — and the part I learned the most from. The product question underneath it: how do you make online presence feel ambient instead of effortful?