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The same core ideas underpin every system on this site. Master them once, then spot them everywhere.
- The System Design Fundamentals HandbookThe load-bearing ideas behind every distributed system — the CAP theorem and consistency models, concurrency and locking, partitioning and replication, and consensus and coordination — each tied to a real worked design you can study interactively.Learn the fundamentals →
- CAP Theorem & Consistency ModelsWhat a distributed system can promise when the network splits — CP vs AP, why "CA" is a myth, PACELC, and the full spectrum from linearizable to eventual consistency. Part of System Design Fundamentals.Learn the fundamentals →
- Consensus, Transactions & CoordinationHow nodes that can crash still agree on one truth — majority quorums, Raft and Paxos, leader election, two-phase commit vs the saga pattern, and idempotency for exactly-once effects. Part of System Design Fundamentals.Learn the fundamentals →
More System Designs
- Design UberBuild a planet-scale ride-hailing system. Learn how to handle real-time location tracking, matching algorithms, scalability, and payments.Read →
- Design a URL ShortenerBuild a URL shortener (think Bitly or TinyURL). Learn how to mint unique short codes with base62, make the read-heavy redirect path sub-millisecond with caching, shard billions of mappings, and track clicks asynchronously.Read →
- Design TwitterBuild Twitter's news feed. Learn the social graph, why fan-out on write beats read-time merging, how a precomputed timeline cache makes feed reads O(1), how ranking surfaces the best tweets, and how a hybrid model solves the celebrity problem.Read →
- Design YouTubeBuild a planet-scale video platform. See how raw uploads become an adaptive-bitrate ladder through an async transcoding pipeline, how a CDN serves immutable segments from the edge, how tiered blob storage holds exabytes affordably, and how view counts stay async.Read →
- Design a Rate LimiterBuild a distributed rate limiter. Learn where to put the check, how to key and tier limits, the token-bucket and sliding-window algorithms, why shared atomic counters in Redis avoid race conditions, and the fail-open vs fail-closed trade-off.Read →
- Design DropboxBuild a file sync engine. See how splitting metadata from bytes, content-addressed block storage with deduplication, delta sync, a push-then-pull notification service, and conflict-safe versioning fit together to keep files consistent across every device.Read →