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📖 System Design Concepts

Foundations, Networking, Security, APIs, Infrastructure, Storage, Caching, Messaging, Consistency, Scalability, Data Pipelines, Distributed Systems, Observability, AI Systems — all in one place.

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🧩 Real-Time Design Problems

Chat, Video, Payments, Geo/Rides, Queues, Social Feeds, Search, AI/LLM, and more. Each problem with full architecture + interview cheat sheet.

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Visual SVG Diagrams

Every concept with clear, interactive architecture diagrams

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Interview Cheat Sheets

"5 things to say" panels — nail the key points interviewers want

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Scale Estimation

Back-of-envelope math — derive architecture from numbers

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Cross-Referenced

Problems link to concepts. Concepts link to problems. Connected.

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Real Company Scale

Slack 10B msg/day, WhatsApp 2B users — real architectures

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Staff/Sr SWE Level

Deep dives into tradeoffs, failure modes, production decisions