LOW LEVEL DESIGN · DESIGN EXERCISES
Model the behavior.
Defend every decision.
Engineer → Senior → Staff. Learn what each concept means, when it applies, why it matters, and how it works in code.
20 authored chapters · 0 planned problems. Existing foundation progress stays separate.
Review the LLD foundations →20 matching problems
LLD-001 · Domain modeling
Parking Lot
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-002 · Domain modeling
Vending Machine
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-003 · Domain modeling
Elevator Controller
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-004 · Domain modeling
Library Management
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-005 · Domain modeling
Tic-Tac-Toe Engine
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-006 · Domain modeling
Chess Engine
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-007 · Domain modeling
Splitwise / Expense Sharing
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-008 · Domain modeling
Movie Ticket Booking
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-009 · Domain modeling
Meeting Room Scheduler
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-010 · Domain modeling
Shopping Cart and Checkout
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-011 · Reusable components
Logging Framework
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-012 · Reusable components
Notification Dispatcher
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-013 · Reusable components
Rate Limiter
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-014 · Reusable components
In-Memory Cache
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-015 · Reusable components
In-Memory File System
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-016 · Reusable components
Pub/Sub Event Bus
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-017 · Reusable components
Task Scheduler / Thread Pool
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-018 · Reusable components
Wallet / Payment Ledger
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-019 · Reusable components
Inventory and Order Fulfillment
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →LLD-020 · Reusable components
Workflow / State-Machine Engine
Local Java 21 reference verified
Entity schemas, relationship diagrams, method contracts, code, failure cases and three levels of follow-up.
Start a design attempt →