Case Studies System Designs
Worked Case Studies system design walkthroughs: the requirements, the trade-offs, real numbers and the component choices behind each design.
LRU Cache: Case Study
Design a production-grade Least Recently Used cache from scratch — covering data structures, eviction, concurrency, distributed sharding, and failure handling.
Case Studies · beginner · 12 min read
Metrics Monitoring and Alerting System
End-to-end design of a production-grade metrics pipeline handling millions of time-series data points per second, with multi-tier storage, anomaly detection, and sub-minute alerting.
Case Studies · advanced · 12 min read
Mint.com: Personal Finance Aggregation
End-to-end design of a personal finance aggregation platform covering bank connectivity, transaction ingestion, categorization, budgeting, and alerting at tens-of-millions-user scale.
Case Studies · intermediate · 12 min read
Nearby Friends: Real-Time Location Sharing at Scale
End-to-end design of a real-time location-sharing system supporting 100M+ users, covering WebSocket fanout, geospatial indexing, privacy controls, and sub-second latency.
Case Studies · advanced · 12 min read
News Feed System Design (Facebook / Twitter Timeline)
Design a scalable news feed that delivers ranked, personalized posts to hundreds of millions of users with sub-200 ms read latency and high write throughput.
Case Studies · intermediate · 12 min read
Notification Service: Push, SMS, and Email at Scale
End-to-end design of a multi-channel notification service handling millions of daily messages across push, SMS, and email with reliability, deduplication, and observability.
Case Studies · intermediate · 12 min read
Online Code Editor and Judge (LeetCode-Style)
End-to-end design of a scalable code execution platform supporting multi-language sandboxed judging, real-time feedback, and millions of daily submissions.
Case Studies · intermediate · 12 min read
Parking Lot System
Design a parking lot management system that handles vehicle entry/exit, spot assignment, fee calculation, and real-time availability tracking across one or more garages.
Case Studies · beginner · 12 min read
Pastebin System Design
Design a URL-shortening and text-sharing service that stores arbitrary blobs, returns short URLs, and serves millions of reads per day with low latency.
Case Studies · beginner · 12 min read
Payment System Design
End-to-end design of a scalable, fault-tolerant payment platform handling authorization, settlement, ledgering, and reconciliation at millions of transactions per day.
Case Studies · advanced · 12 min read
Proximity and Location-Based Service (Yelp Nearby Places)
Design a scalable system that lets users search for businesses within a given radius, handling 100M+ places and thousands of queries per second with low latency.
Case Studies · intermediate · 12 min read
Real-Time Collaborative Document Editing (Google Docs)
Deep-dive into building a Google Docs-style collaborative editor: OT vs CRDT, WebSocket fan-out, conflict resolution, and storage at scale.
Case Studies · advanced · 12 min read
Real-Time Gaming Leaderboard
Design a globally consistent, low-latency leaderboard that ranks millions of players in real time, handles burst score writes, and serves ranked reads in under 10 ms.
Case Studies · intermediate · 12 min read
Recommendation System (Amazon / Netflix Style)
End-to-end design of a real-time and batch recommendation engine serving personalized results at hundreds of thousands of requests per second.
Case Studies · advanced · 12 min read
Reddit: Communities, Voting and Ranking
End-to-end design of Reddit covering subreddit management, post/comment trees, vote aggregation, and the Wilson-score and Hot ranking algorithms at scale.
Case Studies · intermediate · 12 min read
S3-Like Object Storage System
Design a globally distributed, highly durable object storage system supporting billions of objects, multi-region replication, and S3-compatible APIs at petabyte scale.
Case Studies · advanced · 12 min read
Scaling from One User to Millions on AWS
A concrete walkthrough of evolving a web application from a single EC2 instance to a globally distributed, fault-tolerant AWS architecture that handles millions of concurrent users.
Case Studies · intermediate · 12 min read
Search Autocomplete and Typeahead System
Design a low-latency typeahead service that returns ranked prefix suggestions in under 100 ms at 10 000 queries per second, covering ingestion, trie storage, caching, and serving.
Case Studies · intermediate · 12 min read
Search Engine: Google-Like Indexing and Query Serving
End-to-end design of a web-scale search engine covering crawling, inverted-index construction, ranking, and low-latency query serving at billions-of-documents scale.
Case Studies · advanced · 12 min read
Shopify: Multi-Tenant E-Commerce Platform
Deep-dive into designing a multi-tenant e-commerce platform at Shopify scale: tenant isolation, storefront delivery, checkout, payments, and inventory across millions of shops.
Case Studies · advanced · 12 min read
Spotify System Design Case Study
End-to-end design of a music streaming platform serving 600M users, covering audio delivery, recommendations, search, and real-time playback at scale.
Case Studies · intermediate · 12 min read
Stock Exchange Matching Engine
Design a high-throughput, low-latency order matching engine capable of processing millions of orders per second with microsecond-level execution and strict price-time priority.
Case Studies · advanced · 12 min read
Ticket Booking System (Ticketmaster / BookMyShow)
End-to-end design of a high-concurrency ticket booking platform handling seat inventory, payment, and flash-sale traffic spikes for millions of concurrent users.
Case Studies · intermediate · 12 min read
TikTok: Short Video Platform
End-to-end design of a short-video platform handling 1B+ users, covering upload ingestion, transcoding pipelines, recommendation serving, and global CDN delivery.
Case Studies · advanced · 12 min read