The Apache HTTP Server Project is an effort to develop and maintain an open-source HTTP server for modern operating systems including UNIX and Windows NT. The goal of this project is to provide a secure, efficient and extensible server that provides HTTP services in sync with the current HTTP standards.
Apache has been the most popular web server on the Internet since April 1996. The October 2003 Netcraft Web Server Survey found that more than 64% of web sites on the Internet are using Apache, thus making it more widely used than all other web servers combined.