Redis Deep Dive for System Design Interviews
When an interviewer asks you to design a rate limiter, leaderboard, or session store, one technology comes up almost every time: Redis.
Redis delivers sub-millisecond latency by keeping all data in memory, and its rich set of data structures (lists, sets, sorted sets, streams) make it far more than a simple key-value store.
But knowing that Redis is fast is not enough. Interviewers want to see that you understand when to use it, which data structure fits your problem, and how to handle failures and scaling. These decisions reveal your depth of understanding.
This chapter covers the practical knowledge you need: data structure selection, persistence trade-offs, replication strategies, clustering architecture, and battle-tested patterns.
By the end, you will be able to confidently propose Redis in interviews and defend your design choices with clear reasoning.