System Design Tutorials

Welcome to the System Design tutorials! We don’t teach system design the way most interview-prep sites do. We start from the fundamentals and slowly build up to large-scale systems, so the big stuff actually makes sense when you get there.

These tutorials are written for college students, freshers, junior developers, and anyone getting ready for interviews.

What You Will Learn

This series takes you from “what even is scalability?” all the way to designing real systems. Along the way we cover:

• The fundamentals: scalability, high availability, reliability, latency, and the CAP theorem
• How the internet works: DNS, HTTP, TCP, REST APIs, and WebSockets
• Databases: SQL vs NoSQL, indexing, replication, and sharding
• Caching, load balancing, message queues, and CDNs
• Distributed systems, microservices, and common design patterns
• Real case studies like a URL shortener, a chat app, and a notification system

How to Use These Tutorials

• Start with the fundamentals and follow the topics in order for the smoothest path.
• Each lesson builds on the ones before it, so don’t skip ahead too fast.
• Try the design challenges at the end of each lesson. That’s where it really clicks.

Prerequisites

You don’t need much to start. Basic programming knowledge and a bit of curiosity about how big apps like YouTube and WhatsApp work is enough. We explain every new term the first time it shows up.

Getting Started

🚀 Ready to begin? Start with What Happens When You Type a URL into the Browser? to see how the whole web actually works under one simple action.