Design systems that scale and stay up — load balancing, caching, databases, consistency, and the trade-offs behind every choice.

Welcome to System Design: Scaling, Trade-offs, and Real Architectures.

System design is the craft of arranging servers, databases, caches, and queues so a system meets its goals under real-world load — and it lives or dies on trade-offs. This free book teaches the whole toolkit from first principles: requirements and estimation, horizontal scaling and statelessness, load balancing, caching strategies and invalidation, SQL vs NoSQL with replication and sharding, the CAP theorem and consistency, message queues and asynchronous processing, API design and microservices, and reliability with redundancy and graceful degradation. It ends by walking a complete design end to end. Ten focused chapters with clear diagrams and a repeatable method — clarify, estimate, sketch, scale, justify — that lets you reason about almost any system.

This title is part of the ShriIra library and is free to read in full, right here — our small contribution to making world-class knowledge easy to reach.

A note on reading it: open the Contents menu at the top of the reader to jump between chapters, use the Aa menu to set a comfortable text size, theme (light, sepia, or night), and single- or two-page layout. Your place is saved automatically, so you can always pick up where you left off.

We hope it serves you well.

— Shriira Press

Contents

1. Chapter 1 — What System Design Is
2. Chapter 2 — Scalability
3. Chapter 3 — Load Balancing
4. Chapter 4 — Caching
5. Chapter 5 — Databases
6. Chapter 6 — Consistency and the CAP Theorem
7. Chapter 7 — Asynchronous Processing and Message Queues
8. Chapter 8 — APIs and Communication
9. Chapter 9 — Reliability and Availability
10. Chapter 10 — Putting It Together