Apache is one of the widely used web servers on the Internet, developed originally by the Apache group in 1995. This open source HTTP server is Unix-based and supports PERL and PHP languages.

Apache HTTP server is a project supported by Apace Software Foundation (ASF), a non-profit corporation. Their aim was to provide a secure, efficient and extensible HTTP server. Apache server is characterized by a collaborative, consensus based development process with and open and realistic software license from ASF.

Apache contains a number of features ranging from server side programming language support (Perl, Python, PHP) to authentication schemes (mod_access, mod_auth, mod_digest). Other features include SSL and TSL support, proxy module, custom log files, and filtering support. It also contains rewrite engine, a useful URL rewriter.

Apache is one of the components of the popular web server set of programs, the LAMP. Apache is also redistributed as a part of various proprietary packages like Oracle database, IBM WebSphere web application server etc.