Varnish is a website accelerator tool, which has been gaining a lot in popularity in recent years, as it can increase the loading speed of any Internet site, at times even by 100 percent, based on the content itself. This tool is occasionally referred to as an HTTP reverse proxy as well and is used to reduce the overall server load and to enhance the access speed for the site visitors. Each time a visitor loads a page on a given Internet site, the browser request is taken care of by the web server and the requested content is delivered as a response. If the Varnish accelerator is enabled, it caches the pages that the visitor opens and in case any of them is loaded once more, it’s served by Varnish and not by the server directly. The increase in the overall performance comes from the fact that the accelerator handles the web requests considerably quicker than any web server, which leads to much faster browsing speeds for the site visitors. In case any data is modified meanwhile, the cached pages will also be ‘refreshed’ the next time someone attempts to open them.