system-design/
├── 📄 index.md
│
├── 📂 01-fundamentals/             (4 files)
│   ├── what-is-system-design.md
│   ├── functional-vs-non-functional-requirements.md
│   ├── how-to-approach-a-problem.md
│   └── back-of-the-envelope-estimation.md
│
├── 📂 02-building-blocks/          (5 files)
│   ├── client-server-model.md
│   ├── dns-and-cdn.md
│   ├── load-balancing.md
│   ├── proxies.md
│   └── scaling-vertical-vs-horizontal.md
│
├── 📂 03-databases/                (7 files)
│   ├── database-types.md
│   ├── sql-vs-nosql.md
│   ├── cap-and-pacelc.md
│   ├── acid-vs-base.md
│   ├── replication.md
│   ├── sharding-and-partitioning.md
│   └── indexing-basics.md
│
├── 📂 04-caching/                  (3 files)
│   ├── caching-basics.md
│   ├── cache-strategies.md
│   └── eviction-and-invalidation.md
│
├── 📂 05-communication/            (5 files)
│   ├── sync-vs-async.md
│   ├── rest-grpc-graphql.md
│   ├── websockets-and-realtime.md
│   ├── message-queues-and-streaming.md
│   └── event-driven-architecture.md
│
├── 📂 06-architecture-patterns/    (5 files)
│   ├── monolith-vs-microservices.md
│   ├── layered-and-hexagonal.md
│   ├── cqrs-and-event-sourcing.md
│   ├── saga-and-distributed-transactions.md
│   └── serverless.md
│
├── 📂 07-distributed-systems/      (5 files)
│   ├── consistency-models.md
│   ├── consensus-and-leader-election.md
│   ├── clocks-and-ordering.md
│   ├── fault-tolerance-and-redundancy.md
│   └── idempotency-and-retries.md
│
├── 📂 08-reliability-and-scale/    (4 files)
│   ├── availability-and-sla.md
│   ├── rate-limiting-and-throttling.md
│   ├── backpressure-and-circuit-breakers.md
│   └── observability.md
│
├── 📂 09-security/                 (3 files)
│   ├── auth-and-authorization.md
│   ├── encryption-and-tls.md
│   └── common-attacks-and-defenses.md
│
├── 📂 10-interview-guide/          (3 files)
│   ├── the-framework.md
│   ├── trade-off-cheat-sheet.md
│   └── common-mistakes.md
│
└── 📂 11-case-studies/             (30 files)
    ├── design-url-shortener.md
    ├── design-rate-limiter.md
    ├── design-chat-system.md
    ├── design-news-feed.md
    ├── design-video-streaming.md
    ├── design-file-storage.md
    ├── design-ride-sharing.md
    ├── design-payment-system.md
    ├── design-distributed-cache.md
    ├── design-search-autocomplete.md
    ├── design-notification-system.md
    ├── design-web-crawler.md
    ├── design-ticket-booking-system.md
    ├── design-ecommerce-order-system.md
    ├── design-distributed-key-value-store.md
    ├── design-proximity-service.md
    ├── design-collaborative-editor.md
    ├── design-distributed-job-scheduler.md
    ├── design-ad-click-aggregation.md
    ├── design-distributed-lock-service.md
    ├── design-twitter-timeline.md
    ├── design-photo-sharing-app.md
    ├── design-distributed-search-engine.md
    ├── design-api-gateway.md
    ├── design-upi-payment-system.md
    ├── design-short-video-platform.md
    ├── design-realtime-chat-voice.md
    ├── design-property-booking.md
    ├── design-metrics-monitoring.md
    └── design-distributed-message-queue.md