Design a URL shortening service

Design a rate limiter

Design a Notification System

Design a Web Crawler

Design a Distributed Key-Value Store

Design a Unique ID Generator

Design a Payment System

Design a Tinder-like Dating App

Design a Booking.com like Hotel Booking System

Design a Netflix-like Video Streaming Service

Design a Uber-like Ride Sharing Service

Design a Facebook-like News Feed System

Design a Twitter-like Social Networking Service

Design a Instagram-like Photo Sharing Service

Design a WhatsApp-like Instant Messaging Service

Design a Amazon-like E-Commerce Website

Design a Notion-like Collaborative Editing Service

Design a Dropbox-like File Storage Service

Design a Google-like Search Autocomplete System

Design a Google-like Search Engine