Guided Design Process
Each problem walks you through entity identification, relationships, and patterns before you code — the way real interviews work.
IDE-Grade Editor
Monaco Editor (VS Code) with Java, C++, and JavaScript support. Real execution via Piston API with stdout and runtime feedback.
Behavioral Test Cases
LLD-specific tests that validate object behavior — park a car, get a ticket, unpark, check the fee. Not just algorithmic output.
1
Design a Parking Lot
MediumReal World Systems
2Design a Movie Ticket Booking System
MediumReal World Systems
3Design a Vending Machine
MediumState Machines
4Design an Elevator System
HardState Machines
5Design an ATM System
MediumFinancial Systems
6Design a Tic Tac Toe Game
EasyGames
7Design a Blackjack Game
MediumGames
8Design a Unix File Search System
MediumFile Systems