TL;DR — YouTube

Design a video sharing platform like YouTube that allows users to upload, process, and stream videos at massive scale. Unlike Netflix which has curated content, YouTube is user-generated — anyone can upload, and the system must handle wildly varying video quality, formats, and sizes from millions of creators daily. Key features: Upload videos up to 12 hours long in any common format. Transcode uploaded videos into multiple resolutions (144p to 4K/8K).