Originally based on theNCSA HTTPd server, development of Apache began in early 1995 after work on the NCSA code stalled.[9] Apache played a key role in the initial growth of theWorld Wide Web,[10] quickly overtaking NCSA HTTPd as the dominantHTTP server. In 2009, it became the first web server software to serve more than 100 millionwebsites.[11]
As of March 2025[update],Netcraft estimated that Apache served 17.83% of the million busiest websites, with the other top four beingCloudflare at 22.99%,Nginx at 20.11%, andMicrosoftInternet Information Services at 4.16%.[12] 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%.[13]
According toThe Apache Software Foundation, its name was chosen "from respect for the variousNative American nations collectively referred to asApache, well-known for their superior skills in warfare strategy and their inexhaustible endurance".[14] This was in a context in which it seemed that the open internet—based on free exchange of open source code—appeared to be soon subjected to a kind of conquer by proprietary software vendorMicrosoft; Apache co-creatorBrian Behlendorf—originator of the name—saw his effort somewhat parallel that ofGeronimo, Chief of the last of the free Apache peoples.[15][16] But it conceded that the name "also makes a cutepun on 'a patchyweb server'—a server made from a series ofpatches".
Other sources also claim that that the name originated as a pun on 'patchy', including the project's official documentation in 1995, which stated: "Apache is a cute name which stuck. It was based on some existing code and a series of software patches, a pun on 'A PAtCHy' server."[17][18] This documentation did not mention Native American tribes in the context of the name.
But in an April 2000 interview, Behlendorf asserted that the origins of Apache were not a pun, stating:[19]
The name literally came out of the blue. I wish I could say that it was something fantastic, but it was out of the blue. I put it on a page and then a few months later when this project started, I pointed people to this page and said: "Hey, what do you think of that idea?" ... Someone said they liked the name and that it was a really good pun. And I was like, "A pun? What do you mean?" He said, "Well, we're building aserver out of a bunch of software patches, right? So it's a patchy Web server." I went, "Oh, all right." ... When I thought of the name, no. It just sort of connoted: "Take no prisoners. Be kind of aggressive and kick some ass."
In January 2023, the US-based non-profit Natives in Tech accused the Apache Software Foundation ofcultural appropriation and urged them to change the foundation's name, and consequently also the names of the software projects it hosts.[20][21]
When Apache is running underUnix, its process name ishttpd, which is short for "HTTPdaemon".[22]
Apache supports a variety of features, many implemented ascompiledmodules which extend the core functionality. These can range fromauthentication schemes to supportingserver-side programming languages such asPerl,Python,Tcl andPHP. Popular authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A sample of other features includeSecure Sockets Layer andTransport Layer Security support (mod_ssl), aproxy module (mod_proxy), aURL rewriting module (mod_rewrite), custom log files (mod_log_config), and filtering support (mod_include and mod_ext_filter).
Popular compression methods on Apache include the external extension module, mod_gzip, implemented to help with reduction of the size (weight) of web pages served overHTTP.ModSecurity is an open source intrusion detection and prevention engine for Web applications. Apache logs can be analyzed through a Web browser using free scripts, such asAWStats/W3Perl or Visitors.
Virtual hosting allows one Apache installation to serve many differentwebsites. For example, one computer with one Apache installation could simultaneously serveexample.com,example.org,test47.test-server.example.edu, etc.
It supports password authentication anddigital certificate authentication. Because the source code is freely available, anyone can adapt the server for specific needs, and there is a large public library of Apache add-ons.[23]
A more detailed list of features is provided below:
Loadable Dynamic Modules
Multiple Request Processing modes (MPMs) includingEvent-based/Async, Threaded and Prefork.
Instead of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs), which allow it to run in either aprocess-based mode, a hybrid (process andthread) mode, or an event-hybrid mode, in order to better match the demands of each particular infrastructure. Choice of MPM and configuration is therefore important.
For delivering static pages, Apache 2.2 series was considered significantly slower thannginx andvarnish.[40] To address this issue, the Apache developers created the Event MPM, which mixes the use of several processes and several threads per process in anasynchronousevent-based loop.[41][clarification needed] This architecture as implemented in the Apache 2.4 series performs at least as well as event-based web servers, according toJim Jagielski and other independent sources.[42][43][44] However, some independent but significantly outdated benchmarks show that it is still half as fast as nginx, e.g.[45]
The Apache HTTP Servercodebase wasrelicensed to theApache 2.0 License (from the previous 1.1 license) in January 2004,[46] and Apache HTTP Server 1.3.31 and 2.0.49 were the firstreleases using the new license.[47]
TheOpenBSD project did not like the change and continued the use of pre-2.0 Apache versions, effectivelyforking Apache 1.3.x for its purposes.[48][49][50] They initially replaced it withNginx, and soon after made their own replacement, OpenBSD Httpd, based on the Relayd project.[51][52][53][54]
Version 1.1:The Apache License 1.1 was approved by the ASF in 2000: The primary change from the 1.0 license is in the 'advertising clause' (section 3 of the 1.0 license); derived products are no longer required to include attribution in their advertising materials, only in their documentation.
Version 2.0:The ASF adopted the Apache License 2.0 in January 2004. The stated goals of the license included making the license easier for non-ASF projects to use, improving compatibility with GPL-based software, allowing the license to be included by reference instead of listed in every file, clarifying the license on contributions, and requiring a patent license on contributions that necessarily infringe a contributor's own patents.
The Apache HTTP Server Project is a collaborative software development effort aimed at creating a robust, commercial-grade, feature-rich and freely available source code implementation of an HTTP (Web) server. The project is jointly managed by a group of volunteers located around the world, using the Internet and the Web to communicate, plan, and develop the server and its related documentation. This project is part of theApache Software Foundation. In addition, hundreds of users have contributed ideas, code, and documentation to the project.[63][64][65]
Older versions of Apache were vulnerable to adenial-of-service attack calledSlowloris, which creates many simultaneous partially completed requests, exhausting the server's pool of available connections.[66] Since Apache 2.2.15, Apache ships the module mod_reqtimeout as the official solution supported by the developers.[67]
^ab"Upgrading to 2.4 from 2.2".Archived from the original on 2021-05-10. Retrieved2021-05-12.Platform support has been removed for BeOS, TPF, and even older platforms such as A/UX, Next, and Tandem. These were believed to be broken anyway.
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