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🏗 Interview Prep

System Design

Scaling, caching, databases, queues and the classic "design X" questions, each with a diagram you can step through.

📘 Learn it from scratch

Visual, hands-on lessons for every pattern in this topic. Do the lesson, then come back and the questions click.

Scaling from 1 to 1 Million UsersCaching Strategies & Building an LRU CacheLoad BalancersDatabases at Scale: Replication & ShardingQueues & Background JobsAcing System Design Interviews (+ Rate Limiter)

100 questions, most asked first

Ranked by how often each question comes up in real interviews. #1 is the most common.

Any difficulty Easy Medium Hard

All patterns Design interview Scaling basics Caching Load balancing Databases at scale Consistent hashing CAP & consistency Queues & async Rate limiting CDNs & storage Real-time Reliability

Unlock 3 more System Design questions · all 1,200 questions for $39/year (about 11¢ a day)See full access #29Design a pastebinDesign interviewEasy🔒#61Forward proxy vs reverse proxyLoad balancingEasy🔒#82Non-functional requirementsDesign interviewEasy🔒