Redis cache is a caching system that works by temporarily storing information in a key-value data structure. Redis is an open-source, in-memory data structure store used as a database, cache, message broker, and streaming engine. Redis cache is popular because it is available in almost all major programming languages and is well-supported. Redis cache is primarily used as a caching system to speed up websites, but Redis itself is much more powerful than that. It can also be used as a database and a message broker. Redis cache is used as an object caching tool for WordPress websites, which have lots of data objects that need to be accessed regularly. Redis cache stores data in memory, which makes it faster than storing data on a disk or solid-state drive. Redis cache is built to improve performance by storing and manipulating data in-memory, physically closer to the application, which reduces latency and increases throughput. Redis cache is used to improve application performance by supporting common application architecture patterns such as data cache, session store, messaging, and queues.