Analytics vs Transactional Systems OLTP (Online Transaction Processing) systems like PostgreSQL are optimized for short, frequent reads and writes to […]

Problem Overview Design a hotel or short-term rental booking system like Airbnb or Booking.com. Users search for available properties in

Why Recommendations Matter Netflix reports that 80% of content watched is discovered through recommendations. Spotify generates 30% of its streams

Problem Overview Design a location-based service that allows users to find nearby businesses (Yelp) or navigate between locations (Google Maps).

Why Payment Systems Are Hard Payment systems are among the hardest distributed systems to design because money movement requires exactly-once

What Is a Web Crawler? A web crawler (spider) systematically browses the web, downloading pages and extracting links to discover

Problem Overview Design a file storage and sync service like Dropbox or Google Drive. Users can upload files up to

The Core Challenge Real-time collaborative editing requires multiple users to edit the same document simultaneously and see each other changes

What Is a CDN? A Content Delivery Network is a globally distributed network of servers (Points of Presence, or PoPs)

Problem Overview Design a leaderboard and matchmaking system for a multiplayer game with 50 million players. The leaderboard shows global

What Is a Typeahead System? A typeahead (search autocomplete) system returns a ranked list of query completions as the user

Ad serving is at the core of Google and Meta businesses and is one of the highest-stakes systems in the