Public Solutions
System Design Solutions
Full architecture walkthroughs for the most popular system design questions. Each solution breaks down components, tradeoffs, failure modes, and scoring — so you can benchmark your own designs.
Cake Shop 2 - Scaling Up
The bakery goes viral on social media. Handle 500 k daily visitors with caching and load balancing.
URL Shortener
Design a URL shortening service (like Bitly) that creates short links and tracks click analytics.
RideShare 1 - City Launch
Launch a ride-hailing app in a single city with real-time driver matching.
Cake Shop 1 - Going Online
A small bakery wants to launch a website for online orders. Design the backend for ~10 k daily visitors.
Payment Gateway 1 - Online Checkout
Build a payment processing service for a mid-size e-commerce store handling 50 k transactions/day.
Video Streaming - On-Demand Platform
Design a Netflix-like video streaming platform serving 100 M users worldwide.
Design Amazon
Design Amazon's e-commerce platform - product catalog, cart, checkout, recommendations, and warehouse fulfillment at 300 M+ users.
Email Newsletter Service
Design an email newsletter platform for creators to manage subscribers, write campaigns, and track opens.
Notification System - Multi-Channel Delivery
Build a platform-wide notification service delivering 100 M messages/day across push, email, SMS, and in-app.
Weather Dashboard API
Design a weather API that aggregates data from multiple providers, caches results, and serves forecasts.
Pastebin Service
Design a Pastebin-like service for sharing text snippets with syntax highlighting and expiration.
Poll & Survey Tool
Design a simple polling/survey tool where users create polls, share them, and see real-time results.
Design WhatsApp
Design WhatsApp's messaging platform - E2E encryption, group chats, media, and offline delivery for 2 B users.
Chat App 1 - Team Messaging
Build a Slack-like team messaging app with channels, DMs, and presence indicators.
Content Delivery Network
Design a CDN with edge caching, cache invalidation, origin shielding, and real-time purge support.
Flash Sale - Inventory Under Pressure
Design a flash sale system where 1 M users compete for 10,000 items in 60 seconds.
Social Feed 1 - MVP Launch
Build a simple social feed app with posts, follows, and a chronological timeline.
E-Commerce Product Search
Design a product search engine with faceted filters, autocomplete, spell correction, and relevance ranking for 5 M products.