| Design Extensible Notification System for Sending Alerts | Open ↗ |
| Design Facebook Live / video streaming | Open ↗ |
| Design Facebook Messenger / WhatsApp | Open ↗ |
| Design File System | Open ↗ |
| Design "find nearby drivers/restaurants" | Open ↗ |
| Design Front Middle Back Queue | Open ↗ |
| Design Google Docs (collaborative editing) | Open ↗ |
| Design Google Maps / nearby search | Open ↗ |
| Design Graph With Shortest Path Calculator | Open ↗ |
| Design HashMap | Open ↗ |
| Design HashSet | Open ↗ |
| Design Hit Counter | Open ↗ |
| Design Hotel Management System | Open ↗ |
| Design In-Memory File System | Open ↗ |
| Design Instagram | Open ↗ |
| Design LinkedIn | Open ↗ |
| Design Linked List | Open ↗ |
| Design Live News Feed System | Open ↗ |
| Design Logging Framework | Open ↗ |
| Design Log Storage System | Open ↗ |
| Design LRU Cache | Open ↗ |
| Design LRU Cache With Time Constraint | Open ↗ |
| Design Memory Allocator | Open ↗ |
| Design Microsoft Teams / a chat system | Open ↗ |
| Design Mint.com | Open ↗ |
| Design Most Recently Used Queue | Open ↗ |
| Design Movie Rental System | Open ↗ |
| Design Movie Ticket Booking System | Open ↗ |
| Design Multi-Module Logging Framework | Open ↗ |
| Design Music Streaming Service like Spotify | Open ↗ |
| Design Netflix / a video streaming service | Open ↗ |
| Design Notification System | Open ↗ |
| Design OneDrive / Dropbox (file sync & storage) | Open ↗ |
| Design Online Food Delivery Service like Swiggy | Open ↗ |
| Design Online Shopping System like Amazon | Open ↗ |
| Design Online Stock Brokerage System | Open ↗ |
| Design Order Checkout and Payment for E-commerce Website | Open ↗ |
| Design Order Management System | Open ↗ |
| Design Order Notification System | Open ↗ |
| Design Parking Lot | Open ↗ |
| Design Parking Lot Pricing System | Open ↗ |
| Design Parking System | Open ↗ |
| Design Pastebin.com (or Bit.ly) | Open ↗ |
| design pattern | Open ↗ |
| Design Phone Directory | Open ↗ |
| Design Pizza Pricing System | Open ↗ |
| Design Pizza Pricing System - Followup | Open ↗ |
| Design Pub Sub System | Open ↗ |
| Design real-time location tracking | Open ↗ |
| Design Recent User Query LRU Cache | Open ↗ |
| Design Restaurant Management System | Open ↗ |
| Design Retry Handler for API Calls | Open ↗ |
| Design Ride-Hailing System Like Uber, Ola | Open ↗ |
| Design Ride-Sharing Service like Uber | Open ↗ |
| Design Ride Sharing System | Open ↗ |
| Design Runtime Data Source Access Layer | Open ↗ |
| Design Search Autocomplete System | Open ↗ |
| Design Service Dependency Impact Analyzer | Open ↗ |
| Design Skiplist | Open ↗ |
| Design Snake and Ladder Game | Open ↗ |
| Design Snake Game | Open ↗ |
| Design Splitwise | Open ↗ |
| Design Splitwise (fare splitting) | Open ↗ |
| Design Spotify Music Streaming | Open ↗ |
| Design Spotify Music Streaming and Search | Open ↗ |
| Design Spreadsheet | Open ↗ |
| Design SQL | Open ↗ |
| Design Stack Overflow | Open ↗ |
| Design Stock Market Investing Platform | Open ↗ |
| Design surge pricing | Open ↗ |
| Design System for Managing Workflows | Open ↗ |
| Design Task Manager | Open ↗ |
| Design the data structures for a social network | Open ↗ |
| Design the Facebook/Instagram News Feed | Open ↗ |
| Design the "People You May Know" / friend graph | Open ↗ |
| Design the Twitter timeline and search (or Facebook feed and search) | Open ↗ |
| Design Tic-Tac-Toe | Open ↗ |
| Design Tic-Tac-Toe / a game engine | Open ↗ |
| Design Tic-Tac-Toe / Chess | Open ↗ |
| Design Tic Tac Toe Game | Open ↗ |
| Design Traffic Signal Control System | Open ↗ |
| Design Twitter | Open ↗ |
| Design Uber Eats / food delivery | Open ↗ |
| Design Uber / Lyft (ride hailing) | Open ↗ |
| Design Underground System | Open ↗ |
| Design Unix "find" command for file search | Open ↗ |
| Design Unix "find" command - with boolean predicates | Open ↗ |
| Design URL Shortener | Open ↗ |
| Design Vending Machine With Exact Payment | Open ↗ |
| Design Video Sharing Platform | Open ↗ |
| Design Warehouse Stores Inventory Updater System | Open ↗ |
| Design YouTube | Open ↗ |
| Destination City | Open ↗ |
| Destroying Asteroids | Open ↗ |
| Destroy Sequential Targets | Open ↗ |
| Detect Capital | Open ↗ |
| Detect Cycles in 2D Grid | Open ↗ |
| Detect Pattern of Length M Repeated K or More Times | Open ↗ |
| Detect Squares | Open ↗ |
| Determine if a Cell Is Reachable at a Given Time | Open ↗ |