Back to System Design
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Phase 9

Expert & Real-World Systems

Study how the world's largest systems are actually built. Apply everything you've learned to design complete systems from scratch, the way you would in an interview or on the job.

1

Designing Instagram: A Deep Dive into Photo Sharing at Scale

Analyze how to design a photo-sharing platform like Instagram. Cover storage, CDN, feed ranking, and how to scale to billions of photos.

case studyinstagramphoto sharing
2

Designing Netflix: Video Streaming, CDN, and Recommendations at Scale

Analyze how to design a video streaming service like Netflix. Cover video encoding, CDN architecture, recommendation systems, and handling millions of concurrent viewers.

case studynetflixstreaming
3

Designing a URL Shortener: Base62 Encoding, Redirects, and Analytics at Scale

Design a URL shortener like Bitly or TinyURL. Cover base62 encoding, distributed ID generation, redirect latency, custom aliases, and async click analytics.

case studyurl shortenerbitly
4

Designing Twitter: Fan-Out Strategies, the Celebrity Problem, and the Home Timeline

Design a Twitter-like social feed. Cover fan-out-on-write vs fan-out-on-read, the celebrity/hot-user problem, follower graph storage, and notification delivery at scale.

case studytwittersocial feed
5

Designing YouTube: Video Upload, Transcoding, and Streaming at Scale

Analyze how to design a video-sharing platform like YouTube. Cover resumable uploads, async transcoding pipelines, adaptive bitrate streaming, CDN delivery, and approximate view counters.

case studyyoutubevideo streaming
6

Designing Uber: Real-Time Location, Dispatch, and Ride Matching

Analyze how to design a ride-hailing platform like Uber. Cover geospatial indexing, real-time location tracking, the dispatch/matching service, surge pricing, and the trip state machine.

case studyuberride hailing
7

Designing WhatsApp: Real-Time Messaging, Presence, and End-to-End Encryption

Analyze how to design a chat system like WhatsApp. Cover persistent WebSocket connections, offline message delivery, last-seen status, group fan-out, and the Signal Protocol.

case studywhatsappmessaging
8

Designing a Distributed Search Engine: Crawling, Indexing, and Ranking Billions of Pages

Analyze how to design a web-scale search engine like Google. Cover distributed crawling, inverted indexes, index sharding, query processing pipelines, and multi-layer caching.

case studysearch engineweb crawler
9

Trade-off Analysis and Decision Frameworks in System Design

Learn to evaluate architectural trade-offs like consistency vs availability, latency vs throughput, and complexity vs flexibility. Use decision matrices and ADRs to make and communicate design decisions.

trade-offsdecision makingADR