Editing ReactOS (section)

{{Short description|Free incomplete Windows NT-like operating system}}
{{Use dmy dates|date=January 2016}}
{{distinguish|React (JavaScript library)|Redox OS}}
{{Infobox OS
| name = ReactOS
| logo = ReactOS logo.svg
| logo size = 180px
| screenshot = ReactOS 0.4.14 desktop screenshot.png
| caption = ReactOS 0.4.14 desktop<ref name="Github ver">{{GitHub|reactos|reactos}}</ref><ref name="DistroWatch ver">{{DistroWatch|reactos|NAME=ReactOS}}</ref>
| developer = Community contributors <br /> The ReactOS developers
| programmed in = [[C (programming language)|C]], [[C++]]<ref>{{cite web |title=ReactOS on Open Hub|url=https://www.openhub.net/p/reactos/analyses/latest/languages_summary |website=openhub.net |publisher=Black Duck Open Hub |access-date=2014-10-24}}</ref>
| family = [[Windows NT]]-like
| working state = [[Software release life cycle#Alpha|Alpha]]
| source model = [[Open-source software|Open-source]]<ref>{{cite web |title=ReactOS on GitHub|website=[[GitHub]]|url=https://github.com/reactos/reactos|access-date=2019-04-27}}</ref>
| released = (partial) {{Start date and age|1998}}
| latest release version = <!-- currently in alpha -->
| latest release date = <!-- currently in alpha -->
| latest preview version = 0.4.15<ref name="0.4.15" /><ref name="Github ver"/><ref name="DistroWatch ver" />
| latest preview date = {{Start date and age|2025|03|21|df=y}}<ref name="0.4.15" />
| marketing target = [[Personal computing]]
| updatemodel = [[CD-ROM]] [[ISO image]], [[QEMU]] image, [[VirtualBox]] image, [[VMware]] image, or [[source code]]<ref name=Download>{{cite web |url=https://www.reactos.org/download |title=Download {{!}} ReactOS Project |website=www.reactos.org |access-date=2017-07-28}}</ref>
| supported platforms = [[IA-32]], [[x86-64]]
| kernel type = [[Hybrid kernel|Hybrid]] (designed to be [[backward compatibility|compatible]] with [[Windows NT|Windows NT family]])
| influenced by = [[Microsoft Windows]]
| ui = [[Graphical user interface|Graphical]] (ReactOS Explorer)
| license = [[GNU General Public License|GPL-2.0-or-later]]{{efn|[[GNU General Public License|GPL-2.0-or-later]] with parts under [[GNU Lesser General Public License|LGPL]] and [[BSD licenses]]}}
| website = {{URL|https://www.reactos.org}}
}}
[[File:ReactOS 0.4.14 Firefox 48 screenshot.png|thumb|ReactOS 0.4.14 running the [[Firefox]] [[web browser]]]]
'''ReactOS''' is a [[Free and open-source software|free and open-source]] [[operating system]] for [[i586]]/[[amd64]] [[personal computer]]s, intended to be [[binary-code compatibility|binary-compatible]] with [[computer program]]s and [[device driver]]s developed for [[Windows Server 2003]] and later versions of Microsoft Windows.<ref>{{Cite news|url=https://www.osnews.com/story/21087/reactos-targets-windows-2003-vista/|title=ReactOS Targets Windows 2003, Vista|last=Holwerda|first=Thom|date=2009-03-05|work=OSNews|access-date=2020-10-14}}</ref><ref>{{cite web |title=ReactOS 0.4.8 released!! |author=vicmarcal |website=ReactOS.org Project News |type=Corporate blog |date=2018-04-14 |url=https://www.reactos.org/project-news/reactos-048-released |access-date=2020-10-14 |archive-url=https://archive.today/20180416011852/https://www.reactos.org/project-news/reactos-048-released |archive-date=16 April 2018 |url-status=live |quote=With software specifically leaving NT5 behind, ReactOS is expanding its target to support NT6+ (Vista, Windows 8, Windows 10) software.}}</ref> ReactOS has been noted as a potential open-source [[drop-in replacement]] for Windows<ref>{{Cite news|url=https://www.heise.de/newsticker/meldung/Russland-erklaert-ReactOS-zu-favorisierter-Windows-Alternative-2722495.html|title=Russland erklärt ReactOS zu favorisierter Windows-Alternative|last=Stahl|first=Louis-F.|date=2015-06-23|work=heise online|access-date=2020-10-14}}</ref><ref name="Spiegel" /><ref name="dvorak" /> and for its information on [[undocumented feature|undocumented]] [[Windows API]]s.<ref name="undocumented" />

ReactOS has been in development since 1996. {{As of|2025|4|df=US}}, it is still considered feature-incomplete [[Software release life cycle#Alpha|alpha software]], and is therefore recommended by the developers only for evaluation and testing purposes.<ref name="chemnitz">{{cite conference |last1=Kupfer |first1=Matthias |last2=Bragin |first2=Aleksey |date=2010-03-14 |title=ReactOS&nbsp;— Das zu Windows binärkompatible Open-Source-Betriebssystem |url=https://chemnitzer.linux-tage.de/2010/vortraege/detail.html?idx=424 |conference=Chemnitzer Linux-Tage |language=de |location=Chemnitz, Germany |access-date=2010-03-15 |conference-url=https://chemnitzer.linux-tage.de/2010/info/}}</ref><ref name="lowendmacreview" /> However, many Windows applications are working, such as [[Adobe Acrobat|Adobe Reader]] 9.3, [[GIMP]] 2.6, and [[LibreOffice]] 5.4.<ref>{{cite news |author=Thom Holwerda |date=2007-11-14 |title=ReactOS Gets OpenOffice.org 2 Support; New Release Plans |url=https://www.osnews.com/story/18921/ReactOS_Gets_OpenOffice_org_2_Support_New_Release_Plans |work=[[OSNews]]}}</ref><ref name="0.4.14-tests">[https://reactos.org/wiki/Tests_for_0.4.14 Tests for 0.4.14] on reactos.org (February 2022)</ref>

ReactOS is primarily written in [[C (programming language)|C]], with some elements, such as ReactOS [[File Explorer]], written in [[C++]]. The project partially implements [[Architecture of Windows NT|Windows API]] functionality and has been ported to the [[x86-64|AMD64]] [[Instruction set architecture|processor architecture]].<ref name=2008review /> ReactOS, as part of the [[free and open-source software|FOSS]] ecosystem, re-uses and collaborates with many other FOSS projects,<ref name=collaboration /><ref name=collaboration2 /> most notably the [[Wine (software)|Wine]] project, which presents a Windows compatibility layer for [[Unix-like]] operating systems.