// the find
ashishps1/awesome-low-level-design
Learn Low Level Design (LLD) and prepare for interviews using free resources.
A study guide for low-level design interviews, covering OOP fundamentals, GoF patterns, UML, and concurrency — with worked problem statements and class diagrams for 30+ systems like parking lots, ride-sharing, and chess. Aimed squarely at developers preparing for machine-coding rounds at product companies. Not a library, not a framework — it's a structured reading list with Java implementations.
The problem set covers the right breadth: easy warmups (vending machine, logging framework) through genuinely hard ones (Splitwise debt simplification, Uber-style dispatch). Class diagrams are included for most problems, which saves time when you want to check your mental model without reading all the code. Multi-language coverage (Java, C++, JavaScript, Python, Go) means you can study the pattern in your interview language rather than translating from one example. The concurrency section goes deeper than most interview prep repos — CAS, reentrant locks, livelock — not just the standard producer-consumer.
The problem files are mostly just requirements and UML with links to external implementations on algomaster.io, so the repo itself is thin — you're being funneled toward a paid course. Most Java implementations use textbook-clean class hierarchies that don't reflect how you'd actually write this code under 45 minutes of interview pressure; there's no discussion of what to cut when time is short. No tests anywhere, which matters because interviewers often ask you to write them. The repo hasn't been touched since February 2026 and some linked resources already redirect to course-gated content.