Interview Practice
System Design Interview Practice
System design interviews test whether you can architect a scalable, reliable system and reason about tradeoffs out loud. Critical for mid-to-senior roles.
Start a free mockWhat the system design interview tests
- Requirements gathering and scoping
- API and data modeling
- Scaling, caching, and bottlenecks
- Tradeoff reasoning (consistency, availability, cost)
How to prepare
- Learn the building blocks: load balancers, caches, queues, databases, sharding, replication.
- Practice a repeatable framework: clarify → estimate → API → data → scale → deep dive.
- Study real systems (feeds, chat, URL shorteners, rate limiters).
- Do timed mock designs and narrate your tradeoffs.
Sample system design interview questions
- Design a URL shortener that serves 10k redirects per second.
- Design a news feed like Facebook or Twitter.
- Design a chat / messaging system.
- Design a rate limiter for a public API.
System Design Interview FAQ
When do system design interviews start mattering?
Usually from mid-level (L4) and up, becoming dominant at senior and staff levels. For new grads it is often light or absent.
Do I need to know exact numbers?
Not exact, but you should be comfortable with back-of-envelope estimation (QPS, storage, bandwidth) to justify design choices. Order-of-magnitude is what matters.
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