Editing Web server (section)

{{Short description|Computer software that distributes web pages}}
{{More citations needed|date=March 2009}}
{{Use dmy dates|date=November 2021}}

[[File: Web server serving static content.png|thumb|221x144px|right|PC clients communicating via the network with a web server serving static content only]]
[[File:Inside and Rear of Webserver.jpg|thumb|300x200px|right|The inside and front of a [[Dell PowerEdge]] server, a computer designed to be mounted in a [[rack mount]] environment. Servers similar to this one are often used as web servers.]]
[[File: Wikimedia Foundation Servers-8055 35.jpg|thumb|300x200px|right|Multiple web servers may be used for a high-traffic website.]]
[[File:Wikimedia_Servers-0051_10.jpg|thumb|320x213px|right| [[Server farm]] with thousands of web servers used for super-high traffic websites]]
[[File:Acorplan120m.jpg|thumb|160x120px|right|[[Asymmetric digital subscriber line|ADSL]] modem running an [[Embedded HTTP server|embedded web server]] serving [[dynamic web page]]s used for modem configuration]]

A '''web server''' is [[computer]] [[software]] and underlying [[Computer hardware|hardware]] that accepts requests via [[Hypertext Transfer Protocol|HTTP]] (the [[network protocol]] created to distribute [[web content]]) or its secure variant [[HTTPS]]. A user agent, commonly a [[web browser]] or [[web crawler]], initiates communication by making a request for a [[web page]] or other [[Web Resource|resource]] using HTTP, and the [[server (computing)|server]] responds with the content of that resource or an [[List of HTTP status codes|error message]]. A web server can also accept and store resources sent from the user agent if configured to do so.<ref name="web-server-technology">{{Cite book|url=https://books.google.com/books?id=0jExRH3_-hQC&q=%22Web+server%22+-wikipedia&pg=PA14|title=Web Server Technology|author1=Nancy J. Yeager|author2=Robert E. McGrath|year=1996|publisher=Morgan Kaufmann |access-date=2021-01-22|language=en|isbn=1-55860-376-X|archive-date=20 January 2023|archive-url=https://web.archive.org/web/20230120185216/https://books.google.com/books?id=0jExRH3_-hQC&q=%22Web+server%22+-wikipedia&pg=PA14|url-status=live}}</ref><ref name="web-server-sun">{{Cite book|url=https://books.google.com/books?id=EgNKKPxK9fgC&dq=%22Web+server%22+-wikipedia&pg=PT549|title=Sun Web Server: The Essential Guide|author1=William Nelson|author2=Arvind Srinivasan|author3=Murthy Chintalapati|year=2009|publisher=Pearson Education |access-date=2021-10-14|language=en|isbn=978-0-13-712892-1|archive-date=20 January 2023|archive-url=https://web.archive.org/web/20230120185217/https://www.google.it/books/edition/Sun_Web_Server/EgNKKPxK9fgC?hl=en&gbpv=1&dq=%22Web+server%22+-wikipedia&pg=PT549&printsec=frontcover|url-status=live}}</ref><ref>{{Cite web |title=What is a web server? - MDN Web Docs |url=https://developer.mozilla.org/en-US/docs/Learn_web_development/Howto/Web_mechanics/What_is_a_web_server |website=MDN Web Docs |date=13 March 2025 |access-date=2025-03-20}}</ref><ref>{{Cite web |title=What Is a Web Server and How Does It Work? - IT Glossary {{!}} SolarWinds |url=https://www.solarwinds.com/resources/it-glossary/web-server |access-date=2025-04-26 |website=www.solarwinds.com |language=en-us}}</ref><ref>{{Cite web |date=2025-04-26 |title=What are webservers? |url=https://www.akamai.com/glossary/what-are-web-servers |url-status=live |website=Akamai.com}}</ref>

The hardware used to run a web server can vary according to the volume of requests that it needs to handle. At the low end of the range are [[embedded system]]s, such as a [[router (computing)|router]] that runs a small web server as its configuration interface. A high-traffic [[Internet]] [[website]] might handle requests with hundreds of servers that run on racks of high-speed computers.<ref>{{Cite web |title=Study Material on Web Servers - eGyanKosh |url=https://egyankosh.ac.in/bitstream/123456789/72095/1/Unit-9.pdf |website=eGyanKosh |access-date=2025-03-20}}</ref>

A resource sent from a web server can be a pre-existing [[computer file|file]] ([[Static web page|static content]]) available to the web server, or it can be generated at the time of the request ([[Dynamic web page|dynamic content]]) by another [[Computer program|program]] that communicates with the server software. The former usually can be served faster and can be more easily [[web cache|cached]] for repeated requests, while the latter supports a broader range of applications.

Technologies such as [[Representational state transfer|REST]] and [[SOAP]], which use HTTP as a basis for general computer-to-computer communication, as well as support for [[WebDAV]] extensions, have extended the application of web servers well beyond their original purpose of serving human-readable pages.