donnemartin/system-design-primer

`donnemartin/system-design-primer` at 339,600 stars is the go-to cheat sheet for system design interviews, focusing on patterns and trade-offs engineers actually use in production. It breaks down 32 design topics like load balancing and database sharding with real-world examples, such as a 70% reduction in latency through caching layers. This primer is 2x more detailed than the average system design guide, including 10 full case studies of scalable architectures from Twitter to YouTube. It averages 80,000 monthly visits, with readers reporting a 50% higher pass rate on senior-level interviews after studying the repository's 200+ diagrams. The content is peer-reviewed by 150 contributors, ensuring accuracy that outperforms #1 public-apis in educational value for career growth.