Yes, Redis is a database, specifically, it's an in-memory data structure store. It is often referred to as a "data structure server" because its operations revolve around manipulating various data structures such as strings, hashes, lists, sets, and sorted sets. However, unlike traditional databases that persist data on disk, Redis stores data primarily in memory for faster access.
Redis provides persistence options to store data on disk as well, but it still primarily functions as an in-memory database. Its speed and versatility make it popular for use cases such as caching, real-time messaging systems, leaderboards, analytics, and more.