system-design

The System Design Handbook

A complete, beginner-first path from “I just graduated and I don’t know what a load balancer is” to “I can confidently design and defend a distributed system in a Google interview.”

This repository is a course, not a cheat sheet. Every concept is explained from first principles, with the why before the what, worked numbers, diagrams, real-world war stories, and practice problems with full solutions.

No prior distributed-systems knowledge is assumed. If you can write a for-loop and you have built (or seen) a CRUD web app, you have enough to start.

⚡ Prepping for an interview and short on time? You do not need to read all 16 parts. Start with the Interview Crash Course — the curated 80/20 path (~30 chapters, ~10 case studies, a 1–3 week plan) through the material that actually gets tested.

Who this is for

You are Start at Target
A university student / fresh grad, zero industry experience 00 — Getting Started Junior / Associate SWE, internships
1–3 years experience, comfortable coding, shaky on architecture 01 — Foundations (skim), then 02 — Building Blocks Mid-level SWE (SDE-2, L4)
4+ years, want to pass senior-level design rounds 04 — Distributed Systems and 12 — Case Studies Senior SWE (L5), Staff
Interview is next week ⚡ Interview Crash Course Damage control 🙂

Target companies this guide prepares you for:

The bar differs (see 14 — Company Guides), but the material is the same. What changes is depth, and how much of it you must produce unprompted.

How to use this repo

  1. Read How to Use This Guide first. It explains the study loop (learn → build → explain → mock) that actually makes this stick.
  2. Follow a track from ROADMAP.md — there are 4-week, 12-week, and 24-week plans.
  3. Do not skip the numbers. Back-of-the-Envelope Estimation is the single highest-leverage chapter in this repo.
  4. Explain out loud. Every chapter ends with “Explain it to a five-year-old” prompts and Interview Soundbites. Say them to a wall. Seriously.

Each folder has its own README.md index. Each chapter is self-contained and links to what it depends on.

Table of Contents

Part 0 — Getting Started

Orientation. What this field even is, and how to study it.

Part 1 — Foundations

The physics of computing. Everything later is a consequence of these constraints.

Part 2 — Building Blocks

The Lego bricks. Every system you will ever design is these, arranged differently.

Part 3 — Data & Storage Deep Dive

Part 4 — Distributed Systems

Part 5 — Architecture Patterns

Part 6 — API Design

Part 7 — Security

Part 8 — Observability & Operations

Part 9 — Deployment & Infrastructure

Part 10 — Performance & Scaling Playbooks

Part 11 — The Interview

Part 12 — Case Studies

Full, interview-length designs. Each one: requirements → estimation → API → data model → high-level design → deep dives → bottlenecks → follow-up questions.

Tier 1 — Start here (junior/mid)

Tier 2 — Core interview canon (mid/senior)

Tier 3 — Senior and above

Part 13 — Practice

Part 14 — Company Guides

Part 15 — Resources

Study tracks

Track Time For
🔥 Sprint 4 weeks Interview soon; you already have 2+ years experience
🎯 Standard 12 weeks The default. Fresh grad → interview-ready
🧱 Deep 24 weeks Zero background, or you want genuine mastery, not just interview passing

Full week-by-week breakdowns: ROADMAP.md

Conventions used in this repo

Contributing

Corrections, additions, and new case studies are welcome. See CONTRIBUTING.md.

License

CC BY 4.0 for prose, MIT for code samples.

This site is open source. Improve this page.