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Bestseller Recently updated System Design

The LLD Masterclass

Low-Level Design, from freezing up to interview-ready — object thinking, SOLID, design patterns, and 29 worked case studies.

3.9 (52 ratings) Created by Thomas Berger
Intermediate 129 lessons 50h 45m Updated Jun 2026 English
Preview this course
₹199 ₹499 60% off
incl. GST
left at this price!
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7-day money-back guarantee

What you'll learn

Run a repeatable 8-step framework for any LLD / OOD interview
Turn vague requirements into clean classes, interfaces, and relationships
Apply SOLID and the right design pattern without over-engineering
Sketch class, sequence, and activity diagrams the way interviewers expect
Design thread-safe systems and reason about shared state
Solve 29 real case studies from Parking Lot and LRU Cache to Chess and WhatsApp

This course includes

50h 45m of on-demand content
129 lessons across 16 sections
Access on mobile and desktop
Certificate of completion
Certificate of Achievement
Lifetime access
Curriculum

Course content

16 sections · 129 lessons · 50h 45m

What Is Low-Level Design? Preview 15 min
Why Most Candidates Fail LLD Interviews Preview 15 min
The LLD Roadmap Preview 10 min
Your First Design Challenge 20 min
Knowledge Check · Welcome to the LLD Masterclass 5 min

Procedural vs OO Thinking 25 min
Finding Objects in Real Life 20 min
Attributes vs Behaviors 15 min
Relationships Between Objects 20 min
Modeling the Real World 25 min
Knowledge Check · Thinking in Objects 5 min

Why Public Variables Are Dangerous 15 min
Encapsulation in Practice 20 min
Hiding Complexity 15 min
Interview Questions on Abstraction 15 min
The Good, Bad & Ugly of Inheritance 20 min
Inheritance vs Composition 25 min
Compile-Time vs Runtime Polymorphism 15 min
Building Extensible Systems 25 min
Knowledge Check · OOP Foundations 5 min

Interface vs Abstract Class 20 min
Enums, Generics & Type Safety 20 min
Immutability & Value Objects 20 min
Dependency Injection in Practice 20 min
Error Handling & Exception Design 15 min
Choosing the Right Data Structure 20 min
Knowledge Check · Practical OOP & Clean Code 5 min

Why SOLID Exists 20 min
Single Responsibility Principle 20 min
Open/Closed Principle 20 min
Liskov Substitution Principle 20 min
Interface Segregation Principle 15 min
Dependency Inversion Principle 20 min
SOLID Refactoring Workshop 30 min
Knowledge Check · SOLID Principles Without Boring Theory 5 min

Why UML Matters 10 min
Class Diagrams 20 min
Sequence Diagrams 20 min
Activity Diagrams 15 min
UML Design Exercise 25 min
Knowledge Check · UML for Interviews 5 min

Why Design Patterns Exist 15 min
Pattern Selection Framework 20 min
Singleton 20 min
Factory Method 20 min
Abstract Factory 20 min
Builder 20 min
Prototype 15 min
Adapter 20 min
Decorator 20 min
Facade 15 min
Composite 20 min
Proxy 20 min
Strategy 20 min
Observer 20 min
Command 20 min
State 20 min
Chain of Responsibility 20 min
Template Method 15 min
Iterator 15 min
Mediator 15 min
Pattern Recognition Challenge 25 min
Knowledge Check · Design Patterns Made Practical 5 min

The 8-Step LLD Framework 25 min
Live Design Walkthrough: Parking Lot 35 min
Handling Ambiguous Requirements 20 min
Communicating Like a Senior Engineer 20 min
Knowledge Check · The LLD Interview Framework 5 min

Why Concurrency Breaks Designs 20 min
Locks, synchronized & Atomics 25 min
Thread-Safe Singleton & Lazy Init 20 min
Immutability as a Concurrency Tool 15 min
Producer–Consumer 25 min
Designing Concurrent Systems 30 min
Knowledge Check · Concurrency & Thread-Safety 5 min

Library Management System 35 min
Elevator System 35 min
Vending Machine 30 min
ATM Design 35 min
Snake and Ladder 30 min
Tic Tac Toe 30 min
Knowledge Check · Beginner LLD Case Studies 5 min

Parking Lot 40 min
Movie Ticket Booking 45 min
Splitwise 40 min
Amazon Locker 35 min
Car Rental System 40 min
Food Delivery App 45 min
LRU Cache 35 min
Rate Limiter 40 min
Logging Framework 35 min
Notification Service 40 min
Knowledge Check · Intermediate LLD Case Studies 5 min

Chess 50 min
Online Auction System 45 min
Ride Sharing Platform 50 min
Hotel Management System 45 min
Meeting Scheduler 40 min
Trading Platform 50 min
Pub-Sub / In-Memory Key-Value Store 45 min
Search Autocomplete (Trie) 40 min
Knowledge Check · Advanced Interview Problems 5 min

Naming & Defending Trade-offs 20 min
Where LLD Hands Off to HLD 20 min
Knowledge Check · Trade-offs & The LLD to HLD Boundary 5 min

Reviewing Student Solution #1 25 min
Reviewing Student Solution #2 25 min
Finding Hidden Design Smells 25 min
Refactoring for Scalability 30 min
Junior Engineer Mock 30 min
Mid-Level Engineer Mock 35 min
Senior Engineer Mock 40 min
FAANG-Style Mock Interview 45 min
What a Strong Candidate Sounds Like 25 min
Entity Discovery Checklist 10 min
SOLID Checklist 10 min
Design Pattern Selection Guide 10 min
UML Cheat Sheet 10 min
30-Minute Interview Strategy 15 min
Knowledge Check · Design Reviews, Mocks & Cheat Sheets 5 min

Arena 1 — Design WhatsApp 60 min
Arena 2 — Design Netflix 60 min
Arena 3 — Design Google Drive 60 min
Arena 4 — Design an E-Commerce Platform 60 min
Arena 5 — Design a Product of Your Choice 60 min

Appendix A — Design Glossary 15 min
Appendix B — Common Interview Traps Index 15 min
Appendix C — Study Sequence & Pacing 10 min
Appendix D — Companion Code Repository 10 min

Final Assessment & Certificate of Achievement

49 questions · 60 min · pass 70% · proctored

This course includes a Certificate of Achievement. Work through every lesson, then pass the timed, proctored final assessment to earn a verifiable certificate you can share on LinkedIn or add to your résumé.

  1. Enroll and complete all lessons
  2. Pass the final assessment (70% to pass)
  3. Earn your Certificate of Achievement

Requirements

  • Comfort writing code in any object-oriented language (examples are in Java)
  • Basic understanding of classes, objects, and methods
  • Ideally preparing for LLD / object-oriented design interviews

Description

What you'll learn

A complete path through Low-Level Design — starting from rewiring how you think (procedural vs object thinking), through the four OOP pillars, clean code, SOLID, UML, and every essential design pattern, then concurrency, and finishing with 29 end-to-end case studies and capstone designs. Every lesson is a focused read with diagrams, runnable Java examples, and the exact interview angles graders look for.

How it's organized

  • Foundations — what LLD is, object thinking, the four OOP pillars, and clean, idiomatic code.
  • Principles & notation — SOLID as refactoring moves, and UML class/sequence/activity diagrams in text.
  • Design patterns — the creational, structural, and behavioral patterns that actually come up, plus how to pick one without over-engineering.
  • Interview craft — a repeatable 8-step framework, handling ambiguity, and communicating like a senior engineer.
  • Concurrency — locks, atomics, thread-safe singletons, immutability, and designing systems that stay correct under load.
  • Case studies — 6 beginner, 10 intermediate, and 8 advanced designs (Parking Lot, LRU Cache, Rate Limiter, Chess, Ride Sharing, and more).
  • Reviews, mocks & cheat sheets — learn by critique, rehearse under pressure, and carry quick-reference tools in.
  • The LLD Arena — five capstone challenges (WhatsApp, Netflix, Google Drive, e-commerce, and one of your own).

Who this is for

Engineers preparing for low-level / object-oriented design interviews, and anyone who wants to turn requirements into clean, extensible designs with confidence — from first principles to staff-level trade-offs.

Topics covered

interview-prep design-patterns solid low-level-design object-oriented-design
Your instructor
T

Thomas Berger

Java, Design Patterns & Low-Level Design · 15 yrs · Principal Engineer, Zentech

3.9 course rating 4 courses

Thomas is a 15-year JVM veteran who has shipped large Java platforms and mentored dozens of engineers through senior promotion. He is obsessed with clean object modelling, design patterns applied with restraint, and the kind of low-level design that holds up under a real interview loop.

3.9 course rating · 52 ratings

E
Edythe Frami DDS
1 week ago

Happy with this. The explanations are clear and the structure makes it easy to come back to.

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P
Prof. Pearlie Funk DVM
2 months ago

The best money I have spent on learning this year. Clear, modern, and no fluff.

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M
Merritt Schneider
2 months ago

Sadly a miss. I expected a structured course and got a loose collection of shallow lessons.

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B
Baby West
1 year ago

Frustrating experience — examples that did not work and explanations that left me more confused.

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Frequently asked questions

Yes — once you enroll, the course is yours to revisit forever. New revisions and bonus lessons are added at no extra cost.

Yes — this course includes a Certificate of Achievement. Complete every lesson, then pass the timed, proctored final assessment to earn a shareable, verifiable certificate you can post on LinkedIn or include with job applications.

If the course isn't a fit, request a refund within 7 days of purchase — no questions asked.

Code, slides, and worksheets are downloadable on each lesson page. Videos stream from our CDN so you can watch on any device.

Each course states its level in the hero. If you're comfortable with the prerequisites listed, you're ready to start.

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