I built LiveShop, a mini live-shopping stream UI, to answer a question I kept running into as a frontend-curious grad: tutorials teach you how to render a list, but they never teach you what happens when that list gets hit with the kind of traffic a real live stream produces. So I built something that would force the problem to show up, then fixed it, then measured whether the fix actually worked.

The setup

LiveShop simulates a live-shopping broadcast - the kind of interface a small merchant might use to sell products while streaming. A mock event engine fires chat messages, reactions, and purchase notifications on an interval, standing in for what a real WebSocket connection to a streaming backend would deliver. On top of that sits a chat feed, a scrollable product carousel, and a floating reaction animation layer.

None of that is unusual. The interesting part started once I asked: what happens when message volume spikes?

Where it breaks