Varnish is a web app accelerator platform, which caches content for the sake of quicker response times. It is occasionally called a caching HTTP reverse proxy as well and it interacts between a web server and an Internet browser. When a visitor opens a particular page, its content is requested by the Internet browser, and then the server handles this browser request and sends back the requested info. If Varnish is activated for a certain site, it will cache its pages at the very first visit and in case the visitor visits a cached page once again, the data will be delivered by the caching platform instead of the web server. The improved loading speed is an end result of the substantially faster response time that Varnish offers as compared to any web server software. Of course, this does not mean that the website visitors will continue being served the very same content again and again, since any modification on any of the web pages is reflected in the content that Varnish stores in its system memory.