SystemDesignCrashCourse
A free self-study system design course covering 17 chapters and 13 real-system walkthroughs with 30/60/90-day study plans, aimed at software engineers preparing for tech interviews, from basic networking to distributed systems.
This repository is a self-study course on system design, aimed at software engineers who want to understand how large-scale software systems are built and how to discuss that in a job interview. The content spans 17 chapters, starting from basic networking concepts and building up to advanced topics like distributed consensus, database replication, and multi-region cloud architecture.
The course is structured for engineers at different experience levels. Someone with zero to two years of experience would start at the beginning and work through chapters on networking, databases, and caching. More experienced engineers can skip ahead to advanced topics like distributed systems or microservices. The material includes 13 complete walkthroughs of real systems (the kinds of things you might be asked to design in an interview at a large technology company) covering things like a web search engine, a ride-sharing service, or a payment platform. Each walkthrough follows a standard format: define requirements, estimate scale, sketch the high-level architecture, and examine interesting trade-offs in depth.
Beyond the walkthroughs, the course includes reference material designed to be kept open while reading: a glossary of over 100 technical terms, cheat sheets for quick review, diagram templates, and a set of practice exercises with mock interview frameworks. Study plans for 30, 60, and 90-day timelines help readers pace themselves depending on how much time they have before an interview.
Topics covered include how the internet works at a protocol level, how databases handle heavy read and write loads, how caching layers reduce database pressure, how services communicate through message queues, how large systems stay reliable when individual components fail, and how security is handled for authentication and data protection.
The course is text-based Markdown files organized by chapter in folders. There is no video, no interactive platform, and no login required. You clone the repository or browse it on GitHub and read through it at your own pace.
Where it fits
- Work through the 17 chapters from basic networking to distributed systems to build a complete mental model for system design interviews.
- Use one of the 13 real-system walkthroughs, search engine, ride-sharing, payments, to practice the requirements → architecture → trade-offs interview format.
- Follow the 30-, 60-, or 90-day study plan to pace your interview preparation based on how much time you have available.
- Keep the 100-term glossary and cheat sheets open as a quick reference while studying or during mock interviews.