System Design Interview Roadmap by karanpratapsingh

What is inside

The repository is organised as five chapters plus an introduction:

• Chapter I, Fundamentals: IP, the OSI model, TCP and UDP, DNS, load balancing, clustering, caching, CDNs, proxies, availability, scalability and storage.
• Chapter II, Data management: SQL and NoSQL databases, replication, indexes, normalisation and denormalisation, ACID and BASE, the CAP and PACELC theorems, transactions and distributed transactions, sharding, consistent hashing and database federation.
• Chapter III, Architecture: n-tier design, message brokers and queues, publish and subscribe, enterprise service bus, monoliths and microservices, event driven architecture, event sourcing, CQRS, API gateways, REST, GraphQL and gRPC, long polling, WebSockets and server sent events.
• Chapter IV, Advanced topics: geohashing and quadtrees, circuit breakers, rate limiting, service discovery, SLAs, SLOs and SLIs, disaster recovery, virtual machines and containers, OAuth 2.0 and OpenID Connect, single sign on, and TLS and mTLS.
• Chapter V, Case studies: a general approach to system design interviews, then worked designs for a URL shortener, WhatsApp, Twitter, Netflix and Uber.

It is also sold as an ebook on Leanpub for readers who prefer a PDF or EPUB, but the GitHub version is complete and free.

How popular and current it is

As of September 2026 the repository has about 46,300 GitHub stars and 6,000 forks, and the last commit was in July 2026. The core content changes slowly, which is fine for fundamentals that do not age quickly.

Is it enough on its own?

For vocabulary and concepts, largely yes. Each topic gets enough space to understand the idea without stalling you, which makes it realistic to actually finish. What it does not give you:

• Practice under pressure. Reading five case studies is not the same as designing one yourself in 45 minutes.
• Deep trade off discussion. Topics like consistency models or sharding strategies get a solid overview, not the depth of a book like Designing Data-Intensive Applications.
• Diagrams for every idea. Some sections are text heavy.

How to use it

1. Week one: read chapters I and II end to end. Aim for one or two sessions per chapter.
2. Week two: read chapters III and IV, skipping anything you already use daily.
3. Then practise: for each case study, write your own design first on paper, then compare it with the repository's version.
4. Keep it open as a glossary while you practise other design questions. Being able to explain consistent hashing, quorums and write ahead logs clearly is a large part of sounding prepared.

Compared with the alternatives

• The System Design Primer (also on GitHub) is broader and more link heavy; this one is more readable as a single narrative.
• roadmap.sh's system design roadmap tells you what to learn; this actually teaches it.
• Paid courses add structured practice and more diagrams. This is a good free companion to one, or a cheap way to find out whether you need one.

Best for: students and junior to mid level developers who want a free, finishable grounding in system design concepts before or alongside practice.