What is Varnish Cache?

Varnish Cache is a powerful web application accelerator that can speed up a website by up to 1000 percent. Varnish is typically used for content heavy dynamic websites. It is used by high-profile, high-traffic websites including Wikipedia, online newspaper sites such as The New York Times, The Guardian, The Hindu, Corriere della Sera, social media and content sites such as Facebook, Twitter, Vimeo, and Tumblr. Of the Top 10K sites in the web, around a tenth use this software.