Alex Wu System Design Pdf May 2026

User → Load Balancer → Web servers → Redis cache → DB (sharded by shortCode) Part 2: Core Building Blocks (with war stories) | Chapter | Concept | Alex’s real‑world failure | |---------|---------|----------------------------| | 3 | Load balancing & reverse proxy | Round‑robin killed session affinity → learned sticky sessions + centralized cache | | 4 | Caching (CDN, Redis, write‑through) | “Cache stampede took down our payment service” | | 5 | Databases (SQL vs NoSQL) | Sharded MySQL vs DynamoDB – the “friendship‑ending debate” | | 6 | Message queues (Kafka, SQS) | Why their order‑processing system lost 2% of events (idempotency keys saved them) |

Alex introduces the 4‑Step Framework (Scope – Constraints – Abstract – Deep Dive). Maya practices with a URL shortener. alex wu system design pdf

Here’s a structured story draft: Subtitle: From Zero to Senior Architect – A Story of Breaking Down Complexity Author’s Foreword (The Origin Story) “I failed my first system design interview at a unicorn startup. Not because I couldn’t code – but because I couldn’t see the forest for the servers. This book is the map I wish I had.” Alex Wu – ex-Staff Engineer at a hyper-growth fintech, now a system design interviewer at a FAANG-adjacent company. He wrote this PDF after mentoring 200+ engineers. The story follows a fictional engineer, Maya , from junior dev to lead architect, using real-world scenarios. Part 1: The Wake-Up Call Chapter 1: The 3 AM PagerDuty Night Maya’s simple e‑commerce monolith collapses on Black Friday. The lesson: “Horizontal scaling isn’t a feature – it’s a baseline.” User → Load Balancer → Web servers →