Caching Strategies
Cache-aside, read-through, write-through, write-around, write-back — five answers to the same trade-off between latency, freshness, complexity, and the risk of stale or lost data.
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Building Blocks
Caching Strategies
Cache-aside, read-through, write-through, write-around, write-back — five answers to the same trade-off between latency, freshness, complexity, and the risk of stale or lost data.
Load Balancers
A traffic cop that spreads requests across many servers so none gets overwhelmed — the component that turns one box into a scalable, fault-tolerant pool.
Distributed Systems
Design Problems
Designing a Rate Limiter
Control how many requests a client can make in a window — rejecting the excess with HTTP 429. A study in algorithms, atomic counters, and scaling writes across Redis shards.
Designing a URL Shortener
Turn a long URL into a short, shareable code — and serve billions of redirects per day. A read-heavy system that teaches ID generation, caching, and graceful scaling.
Designing Instagram
A photo-sharing platform for billions: media uploads, a personalized feed, and search. The defining decision is how you fan out a post to followers' timelines.