Memcached (Mem-Cache-D) is a general-purpose distributed memory caching system. It is often used to speed up dynamic database-driven websites by caching data and objects in RAM to reduce the number of times an external data source (such as a database or API) must be read.Memcached is free and open-source software, licensed under the Revised BSD license. Memcached runs on Unix-like operating systems (at least Linux and OS X) and on Microsoft Windows.