WebRTC, DRM & Netflix System Design: The Complete Guide (2026)

What you'll learn: How Netflix streams video to 230 million users without buffering. How DRM actually protects content (and why it's still not perfect). How WebRTC works peer-to-peer. Why you need LiveKit instead of raw WebRTC. And how to design all of it in a system design interview. Written in plain English with real architecture decisions. Table of Contents The Core Problem — Why All This Exists Netflix End-to-End Pipeline Video Encoding & Adaptive Streaming DRM — How Content Protection Actually Works CDN — Why Playback Feels Instant WebRTC — Real-Time Video from Scratch WebRTC vs Socket.IO — When to Use What LiveKit — Why You Should Not Build Raw WebRTC Mini Netflix System Design (Interview Ready) Real Challenges Engineers Face Architecture Decision Guide Interview Answers 1. The Core Problem — Why All This Exists Every piece of technology in this article exists to solve a specific, painful problem. What "just serving a video file" looks like Imagine you're YouTube in 2005. You put