System design interview question
"Design a distributed key-value store — something like DynamoDB or Cassandra. It must scale horizontally, survive node and datacenter failures, and stay available for writes. Tell me what consistency guarantees you offer and why."
the CAP trade-off made concrete, plus the storage-engine and replication machinery that follows from it. It is the most theory-heavy question in this list, and the signal is whether the candidate can turn abstract consistency talk into specific mechanisms — quorums, vector clocks, hinted handoff, LSM trees — and defend the choices.
On Practick another engineer interviews you live for 60 minutes on a question from this bank. They have the full interviewer guide beside the call: the answers to your clarifying questions, the numbers to hand out, a ladder of follow-ups and a scoring rubric. You get the model solution once the session settles. It is free: interview someone for an hour and you have earned your own.
Book a free mock interviewAll 132 system design interview questions
System design mock interviews · DSA interview questions · Free mock interview practice · Browse interviewers · Sign in