system-design-cases

System Design Case Studies

End-to-end designs of real systems — URL shortener, chat, news feed, YouTube, payments — requirements, estimation, high-level design, and the hard deep-dives.

5 units·42 lessons·~37 h

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Foundational designs

The canonical first designs: a key-value store, a URL shortener, a web crawler, a distributed queue.

01 Design a distributed key-value store 32 min 02 Design a URL shortener 28 min 03 Design a web crawler 30 min 04 Design a distributed message queue 32 min 05 Foundational cases: multiple-choice review 13 min 06 Foundational cases: free-recall review 14 min 07 Foundational cases: numbers and config reading 14 min 08 Foundational cases: write a full design doc 240 min

Social & feed

Fan-out, ranking, real-time delivery: notifications, news feed, chat, autocomplete.

01 Design a notification system 30 min 02 Design a news feed 32 min 03 Design a chat system 34 min 04 Design search autocomplete 28 min 05 Social-feed cases: multiple-choice review 13 min 06 Social-feed cases: free-recall review 14 min 07 Social-feed cases: reading config and code 14 min 08 Social-feed cases: design and defend a feed-backed app 240 min

Media & storage

Huge files, huge fan-out reads: video, file sync, object storage, email at scale.

01 Design YouTube 34 min 02 Design Google Drive / Dropbox 36 min 03 Design an object store (S3-like) 35 min 04 Design Gmail-scale email 35 min 05 Media & storage: multiple-choice review 14 min 06 Media & storage: free-recall review 14 min 07 Media & storage: code and config reading 14 min 08 Media & storage: build a chunked, deduplicated upload-and-sync service 300 min

Location & realtime

Spatial indexing and low-latency updates: proximity, nearby friends, maps, leaderboards.

01 Design a proximity service 34 min 02 Design nearby friends 36 min 03 Design Google Maps 38 min 04 Design a realtime leaderboard 32 min 05 Location & realtime: multiple-choice review 13 min 06 Location & realtime: free-recall review 14 min 07 Location & realtime: reading the code and config 14 min 08 Location & realtime: build a live proximity + leaderboard service 240 min

Data & money

Correctness under load and money on the line: metrics, ad aggregation, payments, wallets, exchanges, reservations.

01 Design a metrics & alerting system 34 min 02 Design ad-click aggregation 36 min 03 Design a payment system 38 min 04 Design a digital wallet 36 min 05 Design a stock exchange 38 min 06 Design a hotel reservation system 36 min 07 Data & money: multiple-choice review 13 min 08 Data & money: free-recall review 14 min 09 Data & money: code and config reading 14 min 10 Data & money: build a correct money mover 240 min

Build with this track

Guided projects that exercise what you learn here.

◆ Projects

System Design Dossier

Pick one large system — a URL shortener that has to serve billions of redirects — and write the design document a staff engineer would defend in a review. No running code: the deliverable is rigorous prose, numbers, and diagrams. You move from a vague 'make short links' ask to scoped requirements, a back-of-envelope capacity model, a concrete data model and API, the one bottleneck that actually breaks under load, and an honest map of what you traded away to fix it.

Next track

AWS, hands-on

Deploy real systems on Amazon's cloud — the core model, compute, storage and networking — and come out ready for the AWS Cloud Practitioner and Solutions Architect Associate exams.