Why Your WebRTC App Breaks After 3 Users (And How Zoom Fixes It)

A simple explanation of WebRTC scaling problems and how Mediasoup solves them using SFU architecture. Introduction If you tried building a video calling app using WebRTC, you probably thought it was easy. Until the third or fourth user joins and everything starts breaking. Lag increases Video freezes CPU usage spikes Bandwidth explodes So how do apps like Zoom or Google Meet handle thousands of users smoothly? They don’t use pure WebRTC. They use a smarter architecture. The Simple Promise of WebRTC WebRTC allows direct browser-to-browser communication. No plugins No external software Ultra-low latency At its core, it creates a direct connection between users. Sounds perfect — until it isn’t. Where Things Break WebRTC uses a mesh architecture. That means every user sends video to every other user. Example: 2 users = 1 connection 4 users = 6 connections 10 users = 45 connections This grows exponentially. Mesh Architecture Mesh architecture: every user connects to every other user, causin