Advanced Case Studies — low level design interview guide

Thread-safe designs, distributed patterns, and domain-heavy problems for SDE-2+ interviews.

8 lessons · about 8 hours · Deep Dive · 8 worked case studies

Advanced Case Studies is family 9 of 12 in the Thita low level design course. It holds 0 lessons and 8 worked case studies, and it is marked Deep Dive — depth to reach for once the Interview Soon families are solid.

Lessons in Advanced Case Studies

• Thread-Safe LRU Cache — Depth lesson, worked case study, about 60 minutes, asked at Amazon, Google.
• Design a Pub-Sub System — Depth lesson, worked case study, about 60 minutes, asked at Uber, LinkedIn.
• Design a Task Scheduler — Depth lesson, worked case study, about 60 minutes, asked at Amazon, Uber, Stripe.
• Design a Digital Wallet — Depth lesson, worked case study, about 60 minutes, asked at PayPal, PhonePe, Stripe.
• Design Ride Sharing (Uber/Ola) — Depth lesson, worked case study, about 60 minutes, asked at Uber, Lyft, Ola.
• Design Online Shopping Cart — Depth lesson, worked case study, about 60 minutes, asked at Amazon, Flipkart, Walmart.
• Design Hotel/Meeting Room Booking — Depth lesson, worked case study, about 60 minutes, asked at Booking.com, Airbnb, MakeMyTrip.
• Design In-Memory File System — Depth lesson, worked case study, about 60 minutes, asked at Amazon, Google, Microsoft.

Case studies in Advanced Case Studies

Each one takes a product brief from this family through the whole worked answer — requirements, estimation, API, data model and trade-offs.

The rest of the low level design course

• OOP Foundations & Class Design — OOP pillars, SOLID principles, entity modeling and class extraction. 3 lessons · about 2.5 hours · Interview Soon.
• Strategy & Factory Patterns — #1 and #4 most tested patterns: eliminate if/else chains with Strategy and create objects without specifying exact classes with Factory. 4 lessons · about 2 hours · Interview Soon.
• State Pattern & State Machines — #2 most tested pattern: state transition tables, vending machine case study embedded. 3 lessons · about 2 hours · Interview Soon · 1 worked case study.
• Observer, Decorator & Behavioral — #3 most tested pattern: Observer for event systems, Decorator for middleware chains, Command for undo/redo. 4 lessons · about 2 hours · Interview Soon · 1 worked case study.
• Concurrency Patterns — Race conditions, locks, BlockingQueue, thread pools, and pool sizing. 4 lessons · about 2 hours · Interview Soon.
• Machine Coding & Interview Execution — Three LLD round formats, time budgets, project structure, and pattern recognition. 2 lessons · about 1 hour · Interview Soon.
• Case Studies — Foundational — Top 6 most-asked multi-pattern LLD problems: Parking Lot, Elevator, BookMyShow, Splitwise, Snake & Ladder, Rate Limiter. 6 lessons · about 5 hours · Interview Soon · 6 worked case studies.
• Case Studies — Applied — Advanced combos and data structure design: LRU Cache, Notification System, Chess, Food Delivery. 4 lessons · about 3 hours · Interview Soon · 4 worked case studies.
• Domain-Specific Patterns — Financial systems, progressive design (Coinbase-style), and game engine patterns. 3 lessons · about 3 hours · Deep Dive.
• Machine Coding Mastery — Company-specific machine coding prep and advanced architectural patterns. 2 lessons · about 2 hours · Deep Dive.
• Architecture Teardowns — Deep dives into Spring IoC, Java Collections, and Python data model internals. 3 lessons · about 3 hours · Deep Dive.

Related interview preparation

• Looking for the practice sheet? — Track your progress against every family as a checklist, with company tags and AI interview practice.
• System Design course — The architecture-level companion: APIs, storage, caching, queues and scaling.
• DSA patterns course — The coding round: the algorithmic patterns behind the problems asked alongside design.
• AI mock interviews — Practise explaining a class diagram out loud against an interviewer that asks follow-ups.