Lesson 1 / 20
What is Redis?
Learn what Redis is, why in-memory storage is fast and where it fits alongside a traditional database.
In-memory key-value store
Redis (REmote DIctionary Server) keeps data in RAM instead of on disk, so reads and writes typically take microseconds to under a millisecond, far faster than a disk-based database.
Common use cases
Caching, session storage, real-time leaderboards, rate limiting, pub/sub messaging, and job queues — anywhere speed matters more than complex querying.
Whiteboard vs filing cabinet
A disk database is a filing cabinet — reliable, huge capacity, slower to reach. Redis is the whiteboard on your desk — instantly readable, but wiped if the power's out unless you save a copy.