A cache is a high-speed data storage layer that stores a subset of data in order to serve future requests for that data faster than accessing the data's primary storage location allows.
What is caching
In web development, caching is a way to speed up the response time of your application. When an user makes a request you store that data for the time another user makes the same request. Caching happens both at client level where it is managed by the browser and at server level.
Browser side Cache
Server side Cache
The data in a cache is usually stored in fast access hardware like RAM (Random-access memory), but it can also be used in conjunction with a software component. The primary goal of a cache is to improve data retrieval performance by reducing the need to access the slower storage layer beneath it.