Nginx (pronounced "engine x") is software to provide a web server. It can act as a reverse proxy server for TCP, UDP, HTTP, HTTPS, SMTP, POP3, and IMAP protocols, as well as a load balancer and an HTTP cache. Created by Igor Sysoev in 2002, Nginx runs on Unix, Linux, BSD variants, OS X, Solaris, AIX, HP-UX, and Windows. Released under the terms of a BSD-like license, Nginx is free and open source software. A company of the same name was founded in 2011 to provide support. For Ruby on Rails web sites, Nginx is often deployed with Unicorn, a Rack-based web server. This combines Nginxs good performance serving static content and dealing with many slow client connections with Unicorns ability to efficiently run dynamic page generation code.