Sometimes the best things are the most humble and unassuming ones. Stacks like the Apache HTTP Server, Nginx, and Node.js may be powering more and more of the Web, but let's not overlook their invisible helpers. Varnish is an HTTP caching and acceleration proxy, designed to do one thing and do it well: make Web pages load faster. The creators boast speedups of anywhere from 300 to 1,000 times, "depending on your architecture." Varnish comes with its own configuration language to allow fine-tuning for your needs, add-on modules for dealing with everything from authentication to secure downloads, and extremely liberal licensing.