Real-world system design problems, studied end-to-end — each with a full design write-up and runnable code.

Most system-design resources stop at boxes-and-arrows. This series goes further: every topic ships a written design (requirements → estimation → API → architecture → data model → deep dives → trade-offs) alongside a working implementation you can run, read, and break. Built for system design interview preparation, for learning distributed systems and scalability patterns, and for anyone who learns best from code that actually runs.

More topics are added over time. Each is a standalone repository in this org.

Every topic is its own repository under this org, with a consistent layout:

<topic>/
├── README.md   # the "what" + how to run it
├── DESIGN.md   # the "why" — full high-level design write-up
└── <code>      # runnable implementation (services, infra, frontend)

Start with DESIGN.md for the reasoning, then README.md to run it.

This org is structured to be easy to navigate without a human in the loop:

• One topic = one repository. List them via the GitHub API: GET /orgs/system-design-series/repos.
• Predictable files per repo: README.md (overview + run steps), DESIGN.md (architecture & trade-offs), and source under conventional paths.
• Discoverable by topic tags: each repo is labeled with GitHub topics (e.g. system-design, distributed-systems, scalability) for search and filtering.
• Self-contained: no cross-repo build dependencies — each topic runs on its own.

system design · distributed systems · scalability · high availability · caching · sharding · pub/sub & fan-out · real-time delivery (SSE / WebSockets) · data modeling · pagination · consistency & trade-offs · capacity estimation · system design interview prep

Issues and discussions on any repo are welcome — corrections, alternative designs, and "why not X?" questions make the write-ups better. Each repo is MIT-licensed: learn from it, fork it, build on it.