Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web and in 2009 became the first web server to surpass the 100 million web site milestone. Apache was the first viable alternative to the Netscape Communications Corporation web server, and has since evolved to rival other Unix-based web servers in terms of functionality and performance. The majority of all web servers using Apache are Linux web servers.

Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.