Cracking the System Design Interview

System design interviews are among the toughest rounds in software engineering hiring. Unlike coding tests, they measure how you think about scale, reliability, trade-offs, and distributed systems under ambiguity - and most candidates struggle not because they lack knowledge, but because they've never been taught to reason through architecture decisions.

This book walks through twenty real-world system design problems - from URL shorteners and chat systems to payment platforms, video streaming, fraud detection, and real-time analytics. Each chapter goes beyond the final diagram, explaining how experienced engineers think through requirements, estimate capacity, pick databases, design caching strategies, handle failures, and defend trade-offs. Topics include distributed caches, notification pipelines, rate limiters, search infrastructure, recommendation engines, and more.

By the end of this book, readers will be able to approach system design interviews with structure and confidence, make sound architectural decisions at work, and understand how large-scale distributed systems are designed and operated in production.

What you will learn

● Design scalable distributed systems using practical patterns.

● Understand caching, sharding, replication, and load balancing.

● Build reliable systems with queues and async processing.

Who this book is for

This book is for software engineers, backend developers, full-stack developers, engineering leads, and architects preparing for system design interviews or building scalable distributed systems. Readers should have basic programming and backend development knowledge before starting this book.

Table of Contents

1. URL Shortener

2. API Gateway

3. Distributed Rate Limiter

4. Distributed Cache

5. Feature Flags

6. Metrics and Observability

7. Notification System

8. File Storage (S3-Like)

9. Search Autocomplete

10. News Feed

11. Chat System

12. Video Streaming

13. Payments

14. Web Crawler

15. CDN and Edge Caching

16. Log Ingestion Pipeline

17. Real-Time Analytics Dashboard

18. Fraud Detection

19. Recommendation System

20. Multi-Tenant SaaS Architecture

21. Ads Serving System

Appendix A:Glossary of Terms

Appendix B: System Design Interview Tips