🏗️21 questions
System Design
Scaling, caching, load balancing, CAP, messaging.
ScalingCachingLoad BalancingCAP TheoremMessage QueuesDatabases
Sample Questions (21 live)
ScalingHard
How would you design a URL shortener like bit.ly?
AmazonDeloitteRead →
ScalingEasy
Horizontal vs vertical scaling — which do you reach for and why?
AmazonInfosysTCSRead →
Load BalancingEasy
How does a load balancer distribute traffic, and what algorithms are common?
AmazonInfosysCognizantRead →
CachingEasy
Where do you add caching, and what are the common caching patterns?
AmazonMicrosoftDeloitteRead →
CAP TheoremEasy
Explain the CAP theorem and how it guides real design decisions.
AmazonGoogleMicrosoftRead →
DatabasesMedium
How does database sharding work, and what makes a good shard key?
AmazonGoogleMicrosoftRead →
ScalingMedium
What problem does consistent hashing solve, and how does it work?
AmazonGoogleMicrosoftRead →
DatabasesMedium
How do you scale a read-heavy vs a write-heavy database workload?
AmazonMicrosoftDeloitteRead →
Message QueuesMedium
When do you introduce a message queue, and what does it buy you?
AmazonMicrosoftDeloitteRead →
ScalingMedium
How would you design a distributed rate limiter?
AmazonGoogleMicrosoftRead →
Message QueuesMedium
How would you design a notification system (email / SMS / push) at scale?
AmazonMicrosoftDeloitteRead →
CachingMedium
How does a CDN speed up a global application, and what belongs on it?
AmazonGoogleMicrosoftRead →
DatabasesMedium
Strong vs eventual consistency, and how do quorums (R+W>N) tune it?
AmazonGoogleMicrosoftRead →
ScalingMedium
How would you design a social news feed (timeline)?
AmazonGoogleMicrosoftRead →
DatabasesMedium
How would you design a search system (e.g. product or document search)?
AmazonGoogleMicrosoftRead →
CachingHard
How would you design a distributed cache like Redis Cluster?
AmazonGoogleMicrosoftRead →
Message QueuesHard
How would you design a real-time chat/messaging system?
AmazonGoogleMicrosoftRead →
ScalingHard
How do you do back-of-the-envelope capacity estimation in a design interview?
AmazonGoogleMicrosoftRead →
ScalingHard
What is the hot-key (celebrity) problem, and how do you solve it?
AmazonGoogleMicrosoftRead →
DatabasesHard
What is a Bloom filter, and where does it save huge amounts of work?
AmazonGoogleMicrosoftRead →
DatabasesHard
How would you design a payment/ledger system for correctness under failure?
AmazonMicrosoftbankingRead →
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