Editing Apache HTTP Server

{{Short description|Open-source web server software}}
{{Technical|date=September 2010}}
{{Infobox software
| name = Apache HTTP Server
| logo = Apache HTTP server logo (2019-present).svg
| screenshot = 
| caption = 
| author = [[Robert McCool]]
| developer = [[Apache Software Foundation]]
| released = {{Start date and age|1995}}<ref>{{Cite web|url=https://httpd.apache.org/ABOUT_APACHE.html|title=About the Apache HTTP Server Project|publisher=[[Apache Software Foundation]]|access-date=2008-06-25|archive-url= https://web.archive.org/web/20080607122013/http://httpd.apache.org/ABOUT_APACHE.html|archive-date= 7 June 2008 |url-status= live}}</ref>
| latest release version = {{wikidata|property|preferred|references|edit|Q11354|P348|P548=Q2804309}}
| latest release date = {{Start date and age|{{#time:Y|{{#invoke:wd|qualifier|raw|P348|P577}}}}|{{#time:m|{{#invoke:wd|qualifier|raw|P348|P577}}}}|{{#time:d|{{#invoke:wd|qualifier|raw|P348|P577}}}}}}
| latest preview version = {{wikidata|property|preferred|references|edit|Q11354|P348|P548=Q51930650}}
| latest preview date = {{wikidata|qualifier|preferred|single|Q11354|P348|P548=Q51930650|P577}}
| operating system = [[Unix-like]], [[Microsoft Windows]],<ref>{{cite web|title=Compiling and Installing|url=https://httpd.apache.org/docs/2.4/install.html|website=httpd.apache.org|publisher=The Apache Software Foundation|access-date=9 May 2016|archive-date=7 May 2016|archive-url=https://web.archive.org/web/20160507054137/http://httpd.apache.org/docs/2.4/install.html|url-status=live}}</ref> [[OpenVMS]]
| programming language = [[C (programming language)|C]]<ref>{{cite web |url=https://projects-old.apache.org/indexes/language.html |title=Apache Software Foundation Index: Projects by Programming Language Index |access-date=2016-02-27 |url-status=dead |archive-url=https://web.archive.org/web/20160302011644/http://projects-old.apache.org/indexes/language.html |archive-date=2016-03-02 }}</ref> 
| genre = [[Web server]]
| license = [[Apache License|Apache-2.0]]
| website = {{Official URL}}
}}

The '''Apache HTTP Server''' ({{IPAc-en|ə|ˈ|p|æ|tʃ|i}} {{Respell|ə|PATCH|ee}}) is a [[free and open-source software|free and open-source]] cross-platform [[web server]], released under the terms of [[Apache License|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]],<ref>{{Cite web|url=https://secure1.securityspace.com/s_survey/data/man.201808/apacheos.html|title=OS/Linux Distributions using Apache|website=secure1.securityspace.com|access-date=2018-09-17|archive-date=2018-09-18|archive-url=https://web.archive.org/web/20180918054337/https://secure1.securityspace.com/s_survey/data/man.201808/apacheos.html|url-status=live}}</ref> but current versions also run on [[Microsoft Windows]],<ref>{{Cite web|url=https://httpd.apache.org/docs/2.4/platform/index.html.en|title=Platform Specific Notes - Apache HTTP Server Version 2.4|website=httpd.apache.org|access-date=2019-01-21|archive-date=2019-01-22|archive-url=https://web.archive.org/web/20190122044008/https://httpd.apache.org/docs/2.4/platform/index.html.en|url-status=live}}</ref> [[OpenVMS]],<ref>{{cite web|url=https://vmssoftware.com/products/secure-web-server/|title=Secure Web Server|access-date=2020-10-20|website=vmssoftware.com|archive-date=2020-10-22|archive-url=https://web.archive.org/web/20201022051216/https://vmssoftware.com/products/secure-web-server/|url-status=live}}</ref> and a wide variety of [[Unix-like]] systems. Past versions also ran on [[NetWare]], [[OS/2]] and other operating systems,<ref name=older/> including ports to mainframes.<ref>{{Cite web|url=https://httpd.apache.org/docs/2.4/platform/ebcdic.html.en|title=The Apache EBCDIC Port - Apache HTTP Server Version 2.4|website=httpd.apache.org|access-date=2019-08-16|archive-date=2019-02-27|archive-url=https://web.archive.org/web/20190227063613/http://httpd.apache.org/docs/2.4/platform/ebcdic.html.en|url-status=live}}</ref>

Originally based on the [[NCSA HTTPd]] server, development of Apache began in early 1995 after work on the NCSA code stalled.<ref>{{Cite web |title=About the Apache HTTP Server Project - The Apache HTTP Server Project |url=https://httpd.apache.org/ABOUT_APACHE.html |access-date=2024-02-08 |website=httpd.apache.org}}</ref> Apache played a key role in the initial growth of the [[World Wide Web]],<ref>[http://news.netcraft.com/archives/web_server_survey.html Netcraft Market Share] {{Webarchive|url=https://web.archive.org/web/20100520142533/http://news.netcraft.com/archives/web_server_survey.html |date=2010-05-20 }} for Top Servers Across All Domains August 1995 - today (monthly updated)</ref> quickly overtaking NCSA HTTPd as the dominant [[HTTP]] server. In 2009, it became the first web server software to serve more than 100 million [[website]]s.<ref name="100millionsites">{{Cite web|url=https://news.netcraft.com/archives/2009/02/18/february_2009_web_server_survey.html|title=February 2009 Web Server Survey|date=18 February 2009 |publisher=[[Netcraft]]|access-date=2009-03-29|archive-url= https://web.archive.org/web/20090226092501/http://news.netcraft.com//archives//2009//02//18//february_2009_web_server_survey.html|archive-date= 26 February 2009 |url-status= live}}</ref>

{{As of|2025|03}}, [[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%.<ref>{{Cite web |title=March 2025 Web Server Survey |url=https://www.netcraft.com/blog/march-2025-web-server-survey/ |access-date=2025-04-14 |website=Netcraft News |date=25 March 2025 |language=en-gb |archive-date=2025-04-01 |archive-url=https://web.archive.org/web/20250401132934/https://www.netcraft.com/blog/march-2025-web-server-survey/ |url-status=live }}</ref> 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%.<ref>{{Cite web |url=https://w3techs.com/technologies/overview/web_server |title=Usage Statistics of Web Servers |website=w3techs.com |access-date=2025-04-14}}</ref>

==Name==
According to [[The Apache Software Foundation]], its name was chosen "from respect for the various [[Native Americans in the United States|Native American]] nations collectively referred to as [[Apache]], well-known for their superior skills in warfare strategy and their inexhaustible endurance".<ref name="Apache Foundation">{{cite web |title=Apache Foundation |url=https://www.apache.org/foundation/faq.html#name |website=www.apache.org |access-date=22 August 2018 |archive-date=13 December 2021 |archive-url=https://web.archive.org/web/20211213004914/https://www.apache.org/foundation/faq.html#name |url-status=live }}</ref> 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 vendor [[Microsoft]]; Apache co-creator [[Brian Behlendorf]]—originator of the name—saw his effort somewhat parallel that of [[Geronimo]], Chief of the last of the free Apache peoples.<ref>{{cite web |url=https://www.youtube.com/watch?v=JUt2nb0mgwg&t=234 | archive-url=https://ghostarchive.org/varchive/youtube/20211122/JUt2nb0mgwg| archive-date=2021-11-22 | url-status=live|title="Trillions and Trillions Served" documentary feature on The Apache Software Foundation |publisher=TheApacheFoundation / Youtube |date=2020 }}{{cbignore}}</ref><ref>{{cite web |url=https://www.youtube.com/watch?v=u_dhmGNeNEc&t=2700 | archive-url=https://ghostarchive.org/varchive/youtube/20211122/u_dhmGNeNEc| archive-date=2021-11-22 | url-status=live|title=A Foundation of Trust: Building a Blockchain Future : Brian Behlendorf |date=2020-02-10 |publisher=Long Now Foundation / YouTube }}{{cbignore}}</ref> But it conceded that the name "also makes a cute [[pun]] on 'a patchy [[web server]]'—a server made from a series of [[Patch (computing)|patches]]".

There are other sources for the "patchy" software pun theory, 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."<ref>{{Cite web|url=http://www.apache.org/info.html |title=Information on the Apache HTTP Server Project |date=1997-04-15 |url-status=dead |archive-url=https://web.archive.org/web/19970415054031/http://www.apache.org/info.html |archive-date=April 15, 1997 }}</ref><ref>{{cite web|title=Apache Server Frequently Asked Questions|url=http://www.apache.org/docs/misc/FAQ.html#relate|access-date=15 January 2017|archive-url=https://web.archive.org/web/19970106233141/http://www.apache.org/docs/misc/FAQ.html#relate |archive-date=1997-01-06}}</ref>

But in an April 2000 interview, Behlendorf asserted that the origins of Apache were not a pun, stating:<ref>{{cite web|url=http://www.linux-mag.com/id/472/|title=Apache Power|work=Linux Magazine |first = Robert|last = McMillan|date = 15 April 2000|url-status=usurped|archive-url = https://web.archive.org/web/20190128065900/http://www.linux-mag.com/id/472/ |archive-date = 28 January 2019}}</ref>

{{Blockquote
|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 a [[Server (computing)|server]] 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 of [[cultural appropriation]] and urged them to change the foundation's name, and consequently also the names of the software projects it hosts.<ref>{{Cite web |last=Claburn |first=Thomas |date=2023-01-11 |title=Native Americans ask Apache foundation to change name |url=https://www.theregister.com/2023/01/11/native_american_apache_software_foundation/ |url-status=live |archive-url=https://web.archive.org/web/20230112000842/https://www.theregister.com/2023/01/11/native_american_apache_software_foundation/ |archive-date=2023-01-12 |access-date=2023-01-12 |website=[[The Register]] |language=en}}</ref><ref>{{Cite web |last=Purdy |first=Kevin |date=2023-01-12 |title=Indigenous tech group asks Apache Foundation to change its name |url=https://arstechnica.com/gadgets/2023/01/indigenous-tech-group-asks-apache-foundation-to-change-its-name/ |access-date=2023-01-12 |website=Ars Technica |language=en-us |archive-date=2023-01-12 |archive-url=https://web.archive.org/web/20230112181127/https://arstechnica.com/gadgets/2023/01/indigenous-tech-group-asks-apache-foundation-to-change-its-name/ |url-status=live }}</ref>

When Apache is running under [[Unix]], its process name is {{code|httpd}}, which is short for "HTTP [[Daemon (computing)|daemon]]".<ref>{{cite web |title=Apache Docs |url=https://httpd.apache.org/docs/current/invoking.html |website=httpd.apache.org |access-date=22 August 2018 |archive-date=5 September 2018 |archive-url=https://web.archive.org/web/20180905182937/http://httpd.apache.org/docs/current/invoking.html |url-status=live }}</ref>

==Feature overview==
Apache supports a variety of features, many implemented as [[Compiler|compiled]] [[Modular programming|modules]] which extend the core functionality. These can range from [[authentication]] schemes to supporting [[server-side]] programming languages such as <!-- ATTENTION AUTO-EDITORS, THESE UNDERSCORES ARE INTENTIONAL -->[[mod perl|Perl]], [[mod python|Python]], [[Tcl]] and [[PHP]]. Popular authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest, the successor to mod_digest. A sample of other features include [[Transport Layer Security#SSL 1.0, 2.0, and 3.0|Secure Sockets Layer]] and [[Transport Layer Security]] support ([[mod_ssl]]), a [[proxy server|proxy]] module ([[mod_proxy]]), a [[URL 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<!-- redirects to here -->, implemented to help with reduction of the size (weight) of web pages served over [[HTTP]]. [[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 as [[AWStats]]/[[W3Perl]] or Visitors.

[[Virtual hosting]] allows one Apache installation to serve many different [[websites]]. For example, one computer with one Apache installation could simultaneously serve <code>example.com</code>, <code>example.org</code>, <code>test47.test-server.example.edu</code>, etc.

Apache features configurable error messages, [[Database management system|DBMS]]-based authentication databases, [[content negotiation]] and supports several [[graphical user interface]]s (GUIs).

It supports password authentication and [[digital 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.<ref>{{cite web|url=https://www.webopedia.com/definitions/apache-web-server/|title=Apache Web Server|work=webopedia.com|date=23 March 1998|access-date=12 May 2021|archive-date=12 May 2021|archive-url=https://web.archive.org/web/20210512193103/https://www.webopedia.com/definitions/apache-web-server/|url-status=live}}</ref>

A more detailed list of features is provided below:
* Loadable Dynamic Modules
* Multiple Request Processing modes (MPMs) including [[Event driven programming|Event-based/Async]], Threaded and Prefork.
* Highly scalable (easily handles [[c10k problem|more than 10,000 simultaneous connections]])
* Handling of static files, index files, auto-indexing and content negotiation
* <kbd>.htaccess</kbd> per-directory configuration support<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/howto/htaccess.html | title = Apache HTTP Server Tutorial: .htaccess files | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-02-25 | archive-url = https://web.archive.org/web/20160225155611/http://httpd.apache.org/docs/2.4/howto/htaccess.html | url-status = live }}</ref>
* [[Reverse proxy]] with caching<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_proxy.html | title = mod_proxy | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2018-07-29 | archive-url = https://web.archive.org/web/20180729204047/http://httpd.apache.org/docs/2.4/mod/mod_proxy.html | url-status = live }}</ref>
** [[Load balancing (computing)|Load balancing]]<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_proxy_balancer.html | title = mod_proxy_balancer | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-02-13 | archive-url = https://web.archive.org/web/20160213163641/http://httpd.apache.org/docs/2.4/mod/mod_proxy_balancer.html | url-status = live }}</ref> with in-band health checks
** Multiple load balancing mechanisms
** [[Fault-tolerant design|Fault tolerance]] and Failover with automatic recovery
** [[WebSocket]], [[FastCGI]], [[Simple Common Gateway Interface|SCGI]], [[Apache JServ Protocol|AJP]] and [[uWSGI]] support with caching
** Dynamic configuration<ref>{{cite web|url=https://httpd.apache.org/docs/trunk/howto/reverse_proxy.html#manager|title=Balancer Manager|publisher=Apache.org|access-date=2016-02-19|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304103556/https://httpd.apache.org/docs/trunk/howto/reverse_proxy.html#manager|url-status=live}}</ref>
* [[Transport Layer Security|TLS/SSL]] with [[Server Name Indication|SNI]] and [[OCSP stapling]] support, via [[OpenSSL]] or [[wolfSSL]].
* Name- and IP address-based virtual servers
* [[IPv6]]-compatible
* [[HTTP/2]] support
* Fine-grained authentication and authorization access control<ref>{{cite web|url=https://httpd.apache.org/docs/2.4/howto/auth.html|title=Authentication and Authorization|publisher=Apache.org|access-date=2016-02-19|archive-date=2018-01-31|archive-url=https://web.archive.org/web/20180131130634/http://httpd.apache.org/docs/2.4/howto/auth.html|url-status=live}}</ref>
* [[gzip]] compression and decompression
* URL rewriting<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_rewrite.html | title = mod_rewrite | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-02-13 | archive-url = https://web.archive.org/web/20160213152803/http://httpd.apache.org/docs/2.4/mod/mod_rewrite.html | url-status = live }}</ref>
* Headers<ref>{{cite web | url =  https://httpd.apache.org/docs/2.4/mod/mod_headers.html | title =  mod_headers | publisher =  Apache.org | access-date =  2016-02-19 | archive-date =  2016-02-21 | archive-url =  https://web.archive.org/web/20160221033800/http://httpd.apache.org/docs/2.4/mod/mod_headers.html | url-status =  live }}</ref> and content<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_sed.html | title = mod_sed | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-03-04 | archive-url = https://web.archive.org/web/20160304013210/https://httpd.apache.org/docs/2.4/mod/mod_sed.html | url-status = live }}</ref><ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_substitute.html | title = mod_substitute | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-03-04 | archive-url = https://web.archive.org/web/20160304073406/http://httpd.apache.org/docs/2.4/mod/mod_substitute.html | url-status = live }}</ref> rewriting
* Custom logging with rotation
* Concurrent connection limiting
* Request processing rate limiting
* [[Bandwidth throttling]]
* [[Server Side Includes]]<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/howto/ssi.html | title = Apache httpd Tutorial: Introduction to Server Side Includes | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-02-18 | archive-url = https://web.archive.org/web/20160218133535/http://httpd.apache.org/docs/2.4/howto/ssi.html | url-status = live }}</ref>
* [[IP address]]-based [[geolocation]]
* User and Session tracking<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_usertrack.html | title = mod_usertrack | publisher = Apache.org | access-date = 2021-05-12 | archive-date = 2021-05-12 | archive-url = https://web.archive.org/web/20210512192558/http://httpd.apache.org/docs/2.4/mod/mod_usertrack.html | url-status = live }}</ref>
* [[WebDAV]]
* Embedded [[Perl]], [[PHP]] and [[Lua (programming language)|Lua]] scripting
* [[Common Gateway Interface|CGI]] support<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/howto/cgi.html | title = Apache Tutorial: Dynamic Content with CGI | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2021-11-15 | archive-url = https://web.archive.org/web/20211115181448/https://httpd.apache.org/docs/2.4/howto/cgi.html | url-status = live }}</ref>
* <code>public_html</code> per-user web-pages<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/howto/public_html.html | title = Per-user web directories | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-02-16 | archive-url = https://web.archive.org/web/20160216122731/http://httpd.apache.org/docs/2.4/howto/public_html.html | url-status = live }}</ref>
* Generic expression parser<ref>{{cite web| url = https://httpd.apache.org/docs/2.4/expr.html| title = Expressions in Apache HTTP Server| publisher = Apache.org| access-date = 2016-02-19| archive-date = 2016-02-29| archive-url = https://web.archive.org/web/20160229120307/http://httpd.apache.org/docs/2.4/expr.html| url-status = live}}</ref>
* Real-time status views<ref>{{cite web | url = https://httpd.apache.org/docs/2.4/mod/mod_status.html | title = mod_status | publisher = Apache.org | access-date = 2016-02-19 | archive-date = 2016-02-13 | archive-url = https://web.archive.org/web/20160213154107/http://httpd.apache.org/docs/2.4/mod/mod_status.html | url-status = live }}</ref>
* [[FTP]] support (by a separate module)<ref>{{cite web | url= https://httpd.apache.org/mod_ftp/mod/mod_ftp.html | title= Apache Module: mod_ftp | publisher= Apache.org | access-date= 2017-07-08 | archive-date= 2017-07-10 | archive-url= https://web.archive.org/web/20170710072314/http://httpd.apache.org/mod_ftp/mod/mod_ftp.html | url-status= live }}</ref>

==Performance==
Instead of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs), which allow it to run in either a [[Process (computing)|process]]-based mode, a hybrid (process and [[Thread (computing)|thread]]) 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. Where compromises in performance must be made, Apache is designed to reduce [[Latency (engineering)#Computer hardware and operating systems|latency]] and increase [[throughput]] relative to simply handling more requests, thus ensuring consistent and reliable processing of requests within reasonable time-frames.{{clarify |date=August 2018}}<!--It isn't clear to a non-specialist like me why increasing throughput is different from handling more requests or why reducing latency (which sounds like increasing speed) wouldn't enable you to handle more requests. It also isn't clear how either of these represent a compromise in performance. Also, is Apache doing something that decreases latency and increases throughput _relative_ to what you would get by handling more requests, or is it decreasing latency and increasing throughput _rather_ than handling more requests? If the latter, "rather than" should replace "relative to" in that sentence.-->

For delivering static pages, Apache 2.2 series was considered significantly slower than [[nginx]] and [[Varnish (software)|varnish]].<ref>{{cite web|url=http://nbonvin.wordpress.com/2011/03/14/apache-vs-nginx-vs-varnish-vs-gwan/|title=Serving static files: a comparison between Apache, Nginx, Varnish and G-WAN|work=Spoot!|date=14 March 2011|access-date=23 April 2014|archive-date=24 April 2014|archive-url=https://web.archive.org/web/20140424234153/http://nbonvin.wordpress.com/2011/03/14/apache-vs-nginx-vs-varnish-vs-gwan/|url-status=live}}</ref> To address this issue, the Apache developers created the Event MPM, which mixes the use of several processes and several threads per process in an [[Asynchrony (computer programming)|asynchronous]] [[Event loop|event-based loop]].<ref>{{cite web|url=https://httpd.apache.org/docs/2.2/mod/worker.html|title=worker - Apache HTTP Server Version 2.2|work=apache.org|access-date=2021-05-12|archive-date=2021-05-10|archive-url=https://web.archive.org/web/20210510050745/https://httpd.apache.org/docs/2.2/mod/worker.html|url-status=live}}</ref>{{clarify |date=August 2018 |reason=Mixes the use of xyz with what? Or, if (a) several processes and (b) several processes per thread are the things being mixed, the sentence should read "...Event MPM, which uses several processes and several threads per process...". Also, can someone with more technical knowledge please explain why this approach is advantageous?}} This architecture as implemented in the Apache 2.4 series performs at least as well as event-based web servers, according to [[Jim Jagielski]] and other independent sources.<ref>{{cite web| url = http://people.apache.org/~jim/presos/ACNA11/Apache_httpd_cloud.pdf| title = Apache httpd 2.4| access-date = 2012-02-08| archive-date = 2012-01-27| archive-url = https://web.archive.org/web/20120127033804/http://people.apache.org/~jim/presos/ACNA11/Apache_httpd_cloud.pdf| url-status = live}}</ref><ref>{{cite web|url=http://www.slideshare.net/bryan_call/choosing-a-proxy-server-apachecon-2014|title=Picking a Proxy Server|date=14 April 2014|access-date=19 February 2016|archive-date=3 March 2016|archive-url=https://web.archive.org/web/20160303105755/http://www.slideshare.net/bryan_call/choosing-a-proxy-server-apachecon-2014|url-status=live}}</ref><ref>{{cite web|url=http://blog.matsumoto-r.jp/?p=1812|title=Throughput evaluation of Apache 2.4.1|date=22 February 2012 |access-date=2016-02-19|archive-date=2016-03-02|archive-url=https://web.archive.org/web/20160302133533/http://blog.matsumoto-r.jp/?p=1812|url-status=live}}</ref> However, some independent but significantly outdated benchmarks show that it is still half as fast as nginx, e.g.<ref>{{cite web|url=http://www.eschrade.com/page/performance-of-apache-2-4-with-the-event-mpm-compared-to-nginx/|title=Performance of Apache 2.4 with the event MPM compared to Nginx|work=eschrade.com|date=3 January 2014|access-date=13 March 2014|archive-date=13 March 2014|archive-url=https://web.archive.org/web/20140313213901/http://www.eschrade.com/page/performance-of-apache-2-4-with-the-event-mpm-compared-to-nginx/|url-status=live}}</ref>

==Licensing==
The Apache HTTP Server [[codebase]] was [[Software relicensing|relicensed]] to the [[Apache License|Apache 2.0 License]] (from the previous 1.1 license) in January 2004,<ref>{{Cite web|url=https://www.apache.org/licenses/LICENSE-2.0.html|title=Apache License, Version 2.0|publisher=The Apache Software Foundation|date=January 2004|access-date=2013-05-21|archive-date=2013-05-18|archive-url=https://web.archive.org/web/20130518072534/http://www.apache.org/licenses/LICENSE-2.0.html|url-status=live}}</ref> and Apache HTTP Server 1.3.31 and 2.0.49 were the first [[Software release life cycle|releases]] using the new license.<ref>{{Cite newsgroup|title=FYI: Apache HTTP Server 2.0.49 Released|last=Burton|first=Richard Antony|newsgroup=alt.apache.configuration|url=https://groups.google.com/d/msg/alt.apache.configuration/042hhGcLWUs/rDJdt5b927cJ|access-date=2018-02-16}}</ref>

The [[OpenBSD]] project did not like the change and continued the use of pre-2.0 Apache versions, effectively [[Fork (software development)|forking]] Apache 1.3.x for its purposes.<ref>{{Cite mailing list|url=http://marc.info/?l=openbsd-misc&m=107714762916291|title=The new apache license|last=de Raadt|first=Theo|author-link=Theo de Raadt|mailing-list=openbsd-misc|date=18 February 2004|access-date=2013-05-21}}</ref><ref>{{Cite web|url=http://www.openbsd.org/policy.html|title=Copyright Policy|publisher=OpenBSD|access-date=2013-05-12|archive-date=2017-11-13|archive-url=https://web.archive.org/web/20171113040622/http://www.openbsd.org/policy.html|url-status=live}}</ref><ref>{{cite web |url=http://ports.su/www/apache-httpd-openbsd |title=apache-httpd-openbsd-1.3.20140502p2 – OpenBSD improved and secured version of Apache 1.3 |website=OpenBSD ports |access-date=2014-12-28 |archive-date=2015-03-02 |archive-url=https://web.archive.org/web/20150302031504/http://ports.su/www/apache-httpd-openbsd |url-status=live }}</ref> They initially replaced it with [[Nginx]], and soon after made their own replacement, OpenBSD Httpd, based on the Relayd project.<ref>{{cite news |last1=Marvin |first1=Rob |title=Inside OpenBSD's new httpd Web server |url=https://sdtimes.com/httpd/inside-openbsds-new-httpd-web-server/ |access-date=12 October 2019 |work=SD Times |date=25 March 2015 |archive-date=12 October 2019 |archive-url=https://web.archive.org/web/20191012215958/https://sdtimes.com/httpd/inside-openbsds-new-httpd-web-server/ |url-status=live }}</ref><ref>{{cite web|url=http://www.openbsd.org/faq/upgrade52.html#nginx|title=OpenBSD Upgrade Guide: 5.1 to 5.2|work=openbsd.org|access-date=2014-03-13|archive-date=2017-12-22|archive-url=https://web.archive.org/web/20171222055544/http://www.openbsd.org/faq/upgrade52.html#nginx|url-status=live}}</ref><ref>{{cite web|url=http://undeadly.org/cgi?action=article&sid=20140314080734|date=2014-03-14|title=Heads Up: Apache Removed from Base|website=[[OpenBSD Journal]]|editor=jj|access-date=2014-12-29|archive-date=2014-10-18|archive-url=https://web.archive.org/web/20141018182803/http://www.undeadly.org/cgi?action=article&sid=20140314080734|url-status=live}}</ref><ref>{{cite web|url=http://www.openbsd.org/faq/upgrade56.html#ToPorts|title=OpenBSD Upgrade Guide: 5.5 to 5.6|work=openbsd.org|access-date=2014-12-29|archive-date=2014-12-22|archive-url=https://web.archive.org/web/20141222025858/http://www.openbsd.org/faq/upgrade56.html#ToPorts|url-status=live}}</ref>

===Versions===

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.

==Development==
{|class="wikitable" style="float: right; margin-left: 1em;"
|+Versions of Apache HTTP Server
|-
!scope="col"|Version
!scope="col"|Initial release
!scope="col"|Latest release
|-
!scope="row" {{Version|o|1.3}}
|1998-06-06<ref>{{Cite web|url=http://marc.info/?l=apache-httpd-announce&m=90221040625561&w=2|title=Announcement: Apache 1.3.0 Released !|date=1998-06-06|access-date=2015-01-06|archive-date=2018-12-11|archive-url=https://web.archive.org/web/20181211203756/https://marc.info/?l=apache-httpd-announce&m=90221040625561&w=2|url-status=live}}</ref>
|2010-02-03 (1.3.42)<ref>{{cite web|url=http://mail-archives.apache.org/mod_mbox/httpd-announce/201002.mbox/%3C20100203000334.GA19021%40infiltrator.stdlib.net%3E|title=Apache HTTP Server 1.3.42 released (final release of 1.3.x)|work=apache.org|access-date=2015-01-06|archive-date=2015-03-11|archive-url=https://web.archive.org/web/20150311184801/http://mail-archives.apache.org/mod_mbox/httpd-announce/201002.mbox/%3C20100203000334.GA19021@infiltrator.stdlib.net%3E|url-status=live}}</ref>
|-
!scope="row" {{Version|o|2.0}}
|2002-04-06<ref>{{Cite web|url=http://marc.info/?l=apache-httpd-announce&m=101810732100356&w=2|title=Official Release: Apache 2.0.35 is now GA|date=2002-04-06|access-date=2015-01-06|archive-date=2018-12-12|archive-url=https://web.archive.org/web/20181212084822/https://marc.info/?l=apache-httpd-announce&m=101810732100356&w=2|url-status=live}}</ref>
|2013-07-10 (2.0.65)<ref>{{cite web|url=http://mail-archives.apache.org/mod_mbox/httpd-announce/201307.mbox/%3C20130710124920.2b8793ed.wrowe%40rowe-clan.net%3E|title=[Announcement] Apache HTTP Server 2.0.65 Released|work=apache.org|access-date=2015-01-06|archive-date=2015-07-28|archive-url=https://web.archive.org/web/20150728000646/http://mail-archives.apache.org/mod_mbox/httpd-announce/201307.mbox/%3C20130710124920.2b8793ed.wrowe@rowe-clan.net%3E|url-status=live}}</ref>
|-
!scope="row" {{Version|o|2.2}}
|2005-12-01<ref>{{Cite web|url=http://marc.info/?l=apache-httpd-announce&m=113347470201565&w=2|title=Apache HTTP Server 2.2.0 Released|date=2005-12-01|access-date=2015-01-06|archive-date=2018-12-12|archive-url=https://web.archive.org/web/20181212145848/https://marc.info/?l=apache-httpd-announce&m=113347470201565&w=2|url-status=live}}</ref>
|2017-07-11 (2.2.34)<ref>{{cite web|url=https://mail-archives.apache.org/mod_mbox/www-announce/201707.mbox/%3CCACsi2512a0dKZm5SEb9GyNH6nMfs1+swpxyui3c+UZUwvi3vvg@mail.gmail.com%3E|title=[Announce] Apache HTTP Server 2.2.34 Released|work=apache.org|access-date=2019-04-03|archive-date=2020-08-21|archive-url=https://web.archive.org/web/20200821113300/https://mail-archives.apache.org/mod_mbox/www-announce/201707.mbox/%3CCACsi2512a0dKZm5SEb9GyNH6nMfs1+swpxyui3c+UZUwvi3vvg@mail.gmail.com%3E|url-status=live}}</ref>
|-
!scope="row" {{Version|c|2.4}}
|2012-02-21<ref>{{Cite web|url=http://marc.info/?l=apache-httpd-announce&m=132983471818384&w=2|title=[ANNOUNCEMENT] Apache HTTP Server 2.4.1 Released|date=2012-02-21|access-date=2015-07-17|archive-date=2021-02-12|archive-url=https://web.archive.org/web/20210212205004/https://marc.info/?l=apache-httpd-announce&m=132983471818384&w=2|url-status=live}}</ref>
|2025-01-23 (2.4.63)<ref>{{cite web |title=Apache HTTP Server 2.4.63 Released |url=https://downloads.apache.org/httpd/Announcement2.4.html |archive-url= |archive-date= |access-date=2025-02-20 |work=apache.org}}</ref>
|-
|colspan="3"|{{Version|l|show=010100}}
|}
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 the [[The Apache Software Foundation|Apache Software Foundation]]. In addition, hundreds of users have contributed ideas, code, and documentation to the project.<ref>{{cite web|url=https://httpd.apache.org/ABOUT_APACHE.html|title=About the Apache HTTP Server Project - The Apache HTTP Server Project|author=Documentation Group|work=apache.org|access-date=2021-05-12|archive-date=2008-06-07|archive-url=https://web.archive.org/web/20080607122013/http://httpd.apache.org/ABOUT_APACHE.html|url-status=live}}</ref><ref>{{cite web| url = http://www.ohloh.net/p/apache| title = The Apache HTTP Server Open Source Project on Ohloh. (n.d.). Ohloh, the open source network. Retrieved November 12, 2012| access-date = February 8, 2012| archive-date = March 9, 2012| archive-url = https://web.archive.org/web/20120309003935/https://www.ohloh.net/p/apache| url-status = live}}</ref><ref>{{cite web|url=http://docs.fedoraproject.org/en-US/Fedora/13/html/Managing_Confined_Services/chap-Managing_Confined_Services-The_Apache_HTTP_Server.html|title=Chapter 4. The Apache HTTP Server|work=fedoraproject.org|access-date=2012-12-03|archive-date=2012-11-25|archive-url=https://web.archive.org/web/20121125111059/http://docs.fedoraproject.org/en-US/Fedora/13/html/Managing_Confined_Services/chap-Managing_Confined_Services-The_Apache_HTTP_Server.html|url-status=dead}}</ref>

Apache 2.4 dropped support for [[BeOS]], [[Transaction Processing Facility|TPF]], [[A/UX]], [[NeXT]], and [[Tandem_Computers|Tandem]] platforms.<ref name=older>{{cite web |url=https://httpd.apache.org/docs/2.4/upgrading.html |title=Upgrading to 2.4 from 2.2 |quote=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. |access-date=2021-05-12 |archive-date=2021-05-10 |archive-url=https://web.archive.org/web/20210510141206/https://httpd.apache.org/docs/2.4/upgrading.html |url-status=live }}</ref>

==Security==
Older versions of Apache were vulnerable to a [[denial-of-service attack]] called [[Slowloris (computer security)|Slowloris]], which creates many simultaneous partially completed requests, exhausting the server's pool of available connections.<ref>{{cite web|url=https://isc.sans.edu/diary/Apache+HTTP+DoS+tool+mitigation/6613|title=Apache HTTP DoS tool mitigation|last=Zdrnja|first=Bojan|publisher=[[SANS Institute]]|date=21 June 2009|access-date=12 November 2021|archive-date=12 November 2021|archive-url=https://web.archive.org/web/20211112130802/https://isc.sans.edu/diary/Apache+HTTP+DoS+tool+mitigation/6613|url-status=live}}</ref> Since Apache 2.2.15, Apache ships the module mod_reqtimeout as the official solution supported by the developers.<ref>{{cite web |url=https://httpd.apache.org/docs/2.4/mod/mod_reqtimeout.html |title=mod_reqtimeout |publisher=Apache.org |access-date=2013-07-03 |archive-date=2013-07-03 |archive-url=https://web.archive.org/web/20130703041319/http://httpd.apache.org/docs/2.4/mod/mod_reqtimeout.html |url-status=live }}</ref>

==See also==
{{Portal|Free and open-source software}}
* [[.htaccess]]
* [[.htpasswd]]
* [[ApacheBench]]
* [[Comparison of web server software]]
* [[IBM HTTP Server]]
* [[LAMP (software bundle)]]
* [[XAMPP]]
* [[List of Apache modules]]
*[[List of free and open-source software packages]]
* [[POSSE project]]
* [[suEXEC]]
* [[Apache Tomcat]] - another web server developed by the Apache Software Foundation

==References==
{{Reflist|30em}}

==External links==
{{Wikibooks|Apache}}
* {{Official website}}

{{Apache Software Foundation}}
{{Web server software}}
{{Web interfaces}}

{{Authority control}}

[[Category:1995 software]]
[[Category:Apache Software Foundation projects| ]]
[[Category:Cross-platform free software]]
[[Category:Free software programmed in C]]
[[Category:Free web server software]]
[[Category:Reverse proxy]]
[[Category:Software using the Apache license]]
[[Category:Unix network-related software]]
[[Category:Web server software for Linux]]