Nginx, pronounced "engine-x," is lightweight software designed for use as a Web and reverse proxy server. The nginx software is licensed under a system similar to Berkeley Software Distribution.
Nginx features support for the Web protocols HTTP, HTTPS, SMTP, POP3 and IMAP. In addition to its proxy and Web server components, nginx incorporates a load balancer and HTTP cache. Nginx can be run on a multitude of operating system platforms, including Linux, BSD, Mac OS X, Solaris, AIX and HP-UX.
Initial development on nginx began in 2002 for use with services provided by Russian search engine and Web portal Rambler. In July 2011, the company NGINX, Inc. was formed with locations in San Francisco, California and Moscow, with the Russian headquarters offering commercial support. Additionally, NGINX Inc. offers consulting to customers looking for custom configurations and special features.
The Apache HTTP Server, another popular Web server, uses a threaded or process-oriented approach to handling Web requests, while nginx utilizes an asynchronous event-driven approach. The modular event-driven architecture used by nginx allows for more predictability in regards to performance when the server is under heavy loads.
A September 2008 survey by Netcraft found that nginx was in use by 2,562,554 domains, including some of the largest websites on the Internet like Hulu and WordPress.com.