⏱ 6 min read Robinhood democratized stock trading with zero-commission trades and a mobile-first experience for 23+ million users. Designing a stock trading platform Read article

⏱ 5 min read Venmo processes billions of dollars in peer-to-peer payments with a unique social feed that makes transactions visible. Designing a P2P Read article

⏱ 5 min read LinkedIn connects 900+ million professionals with a rich social graph, news feed, job marketplace, and messaging system. Designing LinkedIn tests Read article

⏱ 6 min read Reddit is the “front page of the internet” with 50+ million daily active users across 100,000+ active communities (subreddits). Designing Read article

⏱ 5 min read Twitter Trending Topics surfaces the most discussed subjects in real-time from billions of tweets. Designing a trending detection system tests Read article

⏱ 7 min read WhatsApp Status (stories) lets 2+ billion users share photos, videos, and text that disappear after 24 hours. Designing an ephemeral Read article

⏱ 7 min read Google Drive serves 1+ billion users storing documents, spreadsheets, photos, and files with real-time collaboration, sharing, and cross-device sync. While Read article

⏱ 7 min read Airbnb connects 4+ million hosts with 150+ million guests across 220+ countries. Designing an accommodation platform tests your understanding of Read article

⏱ 7 min read GitHub hosts 200+ million repositories for 100+ million developers. Designing a code hosting platform tests your understanding of distributed version Read article

⏱ 7 min read Zoom handles 300+ million daily meeting participants with real-time audio and video. Designing a video conferencing system tests your understanding Read article