Apache HTTP Server

The Apache HTTP Server (/əˈpætʃi/ ə-PATCH-ee) is a free and open-source cross-platform web server, released under the terms of Apache License 2.0. It is developed and maintained by a community of developers under the auspices of the Apache Software Foundation.

The vast majority of Apache HTTP Server instances run on a Linux distribution, but current versions also run on Microsoft Windows, OpenVMS, and a wide variety of Unix-like systems. Past versions also ran on NetWare, OS/2 and other operating systems, including ports to mainframes.

Originally based on the NCSA HTTPd server, development of Apache began in early 1995 after work on the NCSA code stalled. Apache played a key role in the initial growth of the World Wide Web, quickly overtaking NCSA HTTPd as the dominant HTTP server. In 2009, it became the first web server software to serve more than 100 million websites.

As of March 2025, Netcraft estimated that Apache served 17.83% of the million busiest websites, with the other top four being Cloudflare at 22.99%, Nginx at 20.11%, and Microsoft Internet Information Services at 4.16%. According to W3Techs' review of all web sites, in April 2025 Apache was ranked second at 26.4% and Nginx first at 33.8%, with Cloudflare Server third at 23.5%.