Microsoft and open source

{{See also|Open Letter to Hobbyists}}

File:Altair BASIC Paper Tape.jpg on paper tape. In 1976, Microsoft co-founder Bill Gates expressed frustration with most computer hobbyists who were using his company's software without having paid for it.]]

The paradigm of freely sharing computer source code—a practice known as open source—traces back to the earliest commercial computers, whose user groups shared code to reduce duplicate work and costs.{{sfn|Radits|2019|pp=13–14}} Following an antitrust suit that forced the unbundling of IBM's hardware and software, a proprietary software industry grew throughout the 1970s, in which companies sought to protect their software products. The technology company Microsoft was founded in this period and has long been an embodiment of the proprietary paradigm and its tension with open source practices, well before the terms "free software" or "open source" were coined. Within a year of founding Microsoft, Bill Gates wrote an open letter that positioned the hobbyist act of copying software as a form of theft.{{sfn|Radits|2019|pp=17–18}}

Microsoft successfully expanded in personal computer and enterprise server markets through the 1990s, partially on the strength of the company's marketing strategies.{{sfn|Radits|2019|pp=27–28}} By the late 1990s, Microsoft came to view the growing open source movement as a threat to their revenue and platform. Internal strategy memos from this period, known as the Halloween documents, describe the company's potential approaches to stopping open source momentum. One strategy was "embrace-extend-extinguish", in which Microsoft would adopt standard technology, add proprietary extensions, and upon establishing a customer base, would lock consumers into the proprietary extension to assert a monopoly of the space. The memos also acknowledged open source as a methodology capable of meeting or exceeding proprietary development methodology. Microsoft downplayed these memos as the opinions of an individual employee and not Microsoft's official position.{{sfn|Radits|2019|p=27}}

While many major companies worked with open source software in the 2000s,{{sfn|Radits|2019|p=30}} the decade was also marked by a "perennial war" between Microsoft and open source in which Microsoft continued to view open source as a scourge on its business{{sfn|Radits|2019|p=31}} and developed a reputation as the archenemy of the free and open source movement.{{sfn|Radits|2019|p=32}} Bill Gates and Microsoft CEO Steve Ballmer suggested free software developers and the Linux kernel were communist.{{Cite news|last=Lea|first=Graham|date=July 31, 2000|title=MS' Ballmer: Linux is communism|work=The Register|url=https://www.theregister.com/2000/07/31/ms_ballmer_linux_is_communism/|access-date=August 24, 2021}}{{Cite news|last=Penenberg|first=Adam L.|date=November 21, 2005|title=Red Herring|work=Slate|url=https://slate.com/technology/2005/11/the-open-source-movement-isn-t-communism.html|access-date=August 24, 2021}}{{Cite magazine|last=Hernandez|first=Daniela|date=July 4, 2014|title=Watch Steve Ballmer Mock Linux While Dressed as The Matrix's Neo|magazine=Wired|url=https://www.wired.com/2014/07/tech-time-warp-ms-matrix/|access-date=August 24, 2021}} Ballmer also likened Linux to a kind of cancer on intellectual property. Microsoft sued Lindows, a Linux operating system that could run Microsoft Windows applications, as a trademark violation. The court rejected the claim and after Microsoft purchased its trademark, the software changed its name to Linspire.{{sfn|Radits|2019|p=31}}

In 2002, Microsoft began experimenting with 'shared source', including the Shared Source Common Language Infrastructure, the core of .NET Framework.{{Cite web |url=https://boxofcables.dev/microsoft-and-open-source-an-unofficial-timeline/ |title=Microsoft and Open Source: An unofficial timeline |access-date=2020-10-18 |last=Barnes |first=Hayden |date=May 23, 2020 |website=boxofcables.dev}}

In 1998, Microsoft published at least one public beta release of their Services for UNIX (SFU){{cite web|url=http://www.microsoft.com/windows/sfu/unixproresources |title=Microsoft Resources for UNIX professionals |website=Microsoft |accessdate=2023-09-08 |url-status=dead |archiveurl=https://web.archive.org/web/20031022182301/http://www.microsoft.com/windows/sfu/unixproresources/ |archivedate=2003-10-22 }} based on the MKS toolkit, which in turn included some GNU utilities licensed under the GPL. Microsoft fulfilled the obligations imposed by the GPL and other Open Source Software (FLOSS) licenses by offering the source code of these software components and their licenses for download.

Services for UNIX (SFU) v1.0 was released in February 1999.

In April 2004, Windows Installer XML (WiX) was the first Microsoft project to be released under an open-source license, the Common Public License. Initially hosted on SourceForge, it was also the first Microsoft project to be hosted externally.

In June 2004, for the first time Microsoft was represented with a booth at LinuxTag, a free software exposition, held annually in Germany.[http://www.linuxtag.org/2004/exhibitorlist.html LinuxTag 2004 Ausstellerliste] LinuxTag claims to be Europe's largest exhibition for open source software.

In August 2004, Microsoft made the complete source code of the Windows Template Library (WTL) available under the Common Public License and released it through SourceForge. Since version 9.1, the library is licensed under the Microsoft Public License.[https://sourceforge.net/projects/wtl/files/ Download pages for WTL version 7.5, 8.0, 9.0, 9.1 and 10]

In September 2004, Microsoft released its FlexWiki, making its source code available on SourceForge.{{citation |url=http://www.eweek.com/c/a/Windows/FlexWiki-Microsofts-Third-Open-Software-Project/ |title=FlexWiki: Microsofts Third Open Software Project |work=eWeek |date=September 28, 2004 |access-date=April 5, 2012 }} The engine is open source, also licensed under the Common Public License. FlexWiki was the third Microsoft project to be distributed via SourceForge, after WiX and Windows Template Library.

In 2005, Microsoft released the F# programming language under the Apache License 2.0.

In 2006, Microsoft launched its CodePlex open source code hosting site, to provide hosting for open-source developers targeting Microsoft platforms. In the same year, Microsoft ported PHP to Windows under PHP License and also partnered with and commissioned Vertigo Software to create Family.Show, a free and open-source genealogy program, as a reference application for Microsoft's latest UI technology and software deployment mechanism at the time, Windows Presentation Foundation and ClickOnce.[http://blogs.msdn.com/tims/archive/2007/07/17/announcing-family-show-2-0.aspx Tim Sneath : Announcing Family.Show 2.0] - July 17, 2007 MSDN Blogs[http://blogs.msdn.com/tims/archive/2009/02/23/announcing-family-show-v3-our-wpf-reference-application.aspx Tim Sneath : Announcing Family.Show v3 – Our WPF Reference Application] - February 23, 2009, MSDN Blogs{{Cite web|url=https://channel9.msdn.com/Shows/Inside+Out/Vertigo-Software-I-See-Dead-People-with-WPF|title=Vertigo Software: I See Dead People with WPF|via=channel9.msdn.com}} The source code has been published on CodePlex and is licensed under the Microsoft Public License.

File:Steve Ballmer - MIX 2008.jpg]]

In November 2006, Microsoft and Novell announced a broad partnership to make sure Windows interoperates with SUSE Linux. The initial agreement endured until 2012 and included promises not to sue over patents as well as joint development, marketing and support of Windows – Linux interoperability solutions. In addition, Microsoft and Novell agreed to work to ensure documents created in the free OpenOffice.org productivity suite can seamlessly work in Office 2007, and vice versa. Both companies also agreed to develop on translators to improve interoperability between Office Open XML and OpenDocument formats. The company also purchased 70,000 one-year SUSE Linux Enterprise Server maintenance and update subscription coupons from Novell. Microsoft could distribute the coupons to customers as a way to convince them to choose Novell's Linux rather than a competitor's Linux distribution.{{Cite web|last=Mook|first=Nate|date=2006-11-02|title=Novell, Microsoft Ink Linux Partnership|url=https://betanews.com/2006/11/02/novell-microsoft-ink-linux-partnership/|access-date=2021-04-14|website=betanews}}

Microsoft CEO Steve Ballmer acknowledged that more customers are running mixed systems and said about the partnership with Novell:

{{blockquote|While we're going to compete, we're going to collaborate in the right way.|Steve Ballmer, CEO of Microsoft{{Cite web|url=https://money.cnn.com/2006/11/02/technology/microsoft/|title=Linux to work with Windows|date=2006-11-02|first=Grace|last=Wong|website=CNN Money|access-date=2021-04-14}}}}

In June 2007, Tom Hanrahan, former Director of Engineering at the Linux Foundation, became Microsoft's Director of Linux Interoperability.{{Cite web|url=https://www.zdnet.com/article/microsoft-appoints-linux-interoperability-chief/|title=Microsoft appoints Linux interoperability chief|first=Richard|last=Thurston|date=June 11, 2007|website=ZDNet}}{{Cite web|url=https://www.infoworld.com/article/2644663/microsoft-names-linux-interop-director.html|title=Microsoft names Linux interop director|first=Paul|last=Krill|date=June 8, 2007|website=InfoWorld}}

The Open Source Initiative approved the Microsoft Public License (MS-PL) and Microsoft Reciprocal License (MS-RL) in 2007. Microsoft open sourced IronRuby, IronPython, and xUnit.net under MS-PL in 2007.

In 2008, Microsoft joined the Apache Software Foundation{{Cite web|url=https://redmondmag.com/articles/2008/07/28/microsoft-joins-apache-software-foundation.aspx|title=Microsoft Joins Apache Software Foundation -- Redmondmag.com|website=Redmondmag}} and co-founded the Open Web Foundation with Google, Facebook, Sun, IBM, Apache, and others. Also in 2008, Microsoft began distributing the open source jQuery JavaScript library together with the Visual Studio development environment for use within the ASP.NET AJAX and ASP.NET MVC frameworks.{{Cite web |url=http://jquery.com/blog/2008/09/28/jquery-microsoft-nokia/ |title=jQuery, Microsoft, and Nokia |date=2008-09-28 |last=Resig |first=John |publisher=jQuery |work=jQuery Blog |access-date=2009-01-29 }}{{cite web |url=https://weblogs.asp.net/scottgu/jquery-and-microsoft |title=jQuery and Microsoft |last=Guthrie |first=Scott |work=ScottGu's Blog |date=2008-09-28 |access-date=2019-04-15 }}

When Microsoft released Hyper-V in 2008, SUSE Linux Enterprise Server became the first non-Windows operating system officially supported on Hyper-V. Microsoft and Novell signed an agreement to work on interoperability two years earlier.{{Cite web |last=Branscombe |first=Mary |date=2 December 2020 |title=What is Microsoft doing with Linux? Everything you need to know about its plans for open source |url=https://www.techrepublic.com/article/what-is-microsoft-doing-with-linux-everything-you-need-to-know-about-its-plans-for-open-source/ |website=TechRepublic |access-date=6 December 2020}}

Microsoft first began contributing to the Linux kernel in 2009. The CodePlex Foundation, an independent 501(c)(6) non-profit corporation founded by Microsoft and led mostly by Microsoft employees and affiliates, was founded in September 2009. Its goal was to "enable the exchange of code and understanding among software companies and open source communities."{{cite web | url=http://www.hanselman.com/blog/MicrosoftCreatesTheCodePlexFoundation.aspx | title=Microsoft creates the CodePlex foundation | work=Scott Hanselman's Computer Zen | access-date=June 24, 2012}}{{cite web | url=http://www.outercurve.org/About/FAQ/Mission | title=Mission | publisher=Outercurve | access-date=June 24, 2012 | archive-url=https://web.archive.org/web/20140222042551/http://www.outercurve.org/About/FAQ/Mission | archive-date=February 22, 2014 | url-status=dead }} Later in September 2010, the name Outercurve Foundation was adopted.{{cite web | url=http://www.outercurve.org/News/articleType/ArticleView/articleId/19/The-CodePlex-Foundation-Rebrands-Renamed-Outercurve-Foundation | title=The CodePlex Foundation Rebrands, Renamed Outercurve Foundation | publisher=Outercurve | access-date=March 27, 2013 | archive-url=https://web.archive.org/web/20101002150156/http://www.outercurve.org/News/articleType/ArticleView/articleId/19/The-CodePlex-Foundation-Rebrands-Renamed-Outercurve-Foundation | archive-date=October 2, 2010 | url-status=dead }}

In November 2009, Microsoft released the source code of the .NET Micro Framework to the development community as free and open-source software under the Apache License 2.0.{{cite web|url=https://blogs.technet.microsoft.com/port25/2009/11/16/microsoft-to-open-source-the-net-micro-framework/|title=Microsoft to Open Source the .NET Micro Framework|publisher=Microsoft|access-date=2017-02-06|archive-url=https://web.archive.org/web/20181114014924/https://blogs.technet.microsoft.com/port25/2009/11/16/microsoft-to-open-source-the-net-micro-framework/|archive-date=2018-11-14|url-status=dead}}

File:2010 linux-solutions Microsoft speaker Tom Hanrahan at Paris France.JPG in Paris]]

StyleCop, an originally proprietary static code analysis tool by Microsoft, was re-released as an open-source in April 2010 on CodePlex. Based on customer feedback, Microsoft relicensed IronRuby, IronPython, and the Dynamic Language Runtime (DLR) under Apache License 2.0 in July 2010.{{Cite web|url=https://www.zdnet.com/article/microsoft-puts-ironpython-ironruby-under-an-apache-license/|title=Microsoft puts IronPython, IronRuby under an Apache license|first=Mary Jo|last=Foley|date=July 19, 2010|website=ZDNet}}

Microsoft signed the Joomla contributor agreement and started upstreaming improvements in 2010.

In 2011, Microsoft started contributing code to the Samba project. The same year, Microsoft also ported Node.js to Windows, upstreaming the code under Apache License 2.0. The first version of Python Tools for Visual Studio (PTVS) was released in March 2011. After acquiring Skype in 2011, Microsoft continued maintaining the Skype Linux client.

In July 2011, Microsoft was the fifth largest contributor to the Linux 3.0 kernel at 4% of the total changes.{{Cite web|url=https://www.zdnet.com/article/top-five-linux-contributor-microsoft/|title=Top Five Linux Contributor: Microsoft|first=Steven J.|last=Vaughan-Nichols|date=July 17, 2011|website=ZDNet|access-date=July 17, 2021}}{{Cite web|url=https://lwn.net/Articles/451243/|title=Who wrote 3.0 - from two points of view|first=Jonathan|last=Corbet|date=July 13, 2011|website=LWN.net|access-date=July 17, 2021}} The company became a partner with LinuxTag for their 2011 event and also sponsored LinuxTag 2012.{{Cite web|url=https://www.phoronix.com/scan.php?page=news_item&px=MTEwNzE|title=Microsoft: The Unlikely Sponsor Of Linux - Phoronix|website=www.phoronix.com}}{{Cite web|url=https://www.phoronix.com/scan.php?page=news_item&px=MTEwNDk|title=LinuxTag 2012 Gathers Linux Stakeholders In Berlin - Phoronix|website=www.phoronix.com}}

In 2012, Microsoft began hosting Linux virtual machines in the Azure cloud computing service and CodePlex introduced git support. The company also ported Apache Hadoop to Windows, upstreaming the code under MIT License. In March 2012, a completely rewritten version of ChronoZoom was made available as open source[http://newscenter.berkeley.edu/2012/03/14/chronozoom-a-deep-dive-into-the-history-of-everything/ UC Berkeley ChronoZoom 2.0 Beta Press Release] via the Outercurve Foundation. Also, ASP.NET, ASP.NET MVC, ASP.NET Razor, ASP.NET Web API, Reactive extensions, and IL2JS (an IL to JavaScript compiler) were released under Apache License 2.0. The TypeScript programming language was released under Apache License 2.0 in 2012. It was the first Microsoft project hosted on GitHub. In June 2012, Microsoft contributed Open Management Infrastructure to The Open Group with the goal "to remove all obstacles that stand in the way of implementing standards-based management so that every device in the world can be managed in a clear, consistent, coherent way and to nurture [and] spur a rich ecosystem of standards-based management products."{{citation|url=http://blogs.technet.com/b/windowsserver/archive/2012/06/28/open-management-infrastructure.aspx|title=Open Management Infrastructure|publisher=Microsoft Windows Server Blog |date=June 28, 2012|url-status=dead|archive-url=https://web.archive.org/web/20160126224246/http://blogs.technet.com/b/windowsserver/archive/2012/06/28/open-management-infrastructure.aspx|archive-date=2016-01-26}}

In 2013, Microsoft relicensed the xUnit.net unit testing tool for the .NET Framework under Apache License 2.0 and transferred it to the Outercurve Foundation. Also in 2013, Microsoft added Git support to Visual Studio and Team Foundation Server using libgit2, the most widely deployed version of Git. The company is dedicating engineering hours to help further develop libgit2 and working with GitHub and other community programmers who devote time to the software.{{Cite web|url=https://www.cio.com/article/2388760/microsoft-embraces-open-source-git-for-development-tools.html|title=Microsoft embraces open-source Git for development tools|first=Joab|last=Jackson|date=January 30, 2013|website=CIO}}

File:Microsoft_Linux.jpg in 2014]]

In 2014, Satya Nadella was named the new CEO of Microsoft. Microsoft began to adopt open source into its core business. In contrast to Ballmer's stance, Nadella presented a slide that read, "Microsoft loves Linux".{{sfn|Radits|2019|p=32}} At the time of the acquisition of GitHub, Nadella said of Microsoft, "We are all in on open source." As the industry trended towards cloud, embedded, and mobile computing, Microsoft turned to open source to stay apace in these open source dominated fields. Microsoft's adoption of open source included several surprising turns.

File:Miguel de Icaza at PDC (2986319846).jpg, founding member of the Mono, and Xamarin projects and member of the board of directors of the .NET Foundation]]

In 2014, the company opened the source of its .NET Framework to promote its software ecosystem and stimulate cross-platform development. Microsoft also started contributing to the OpenJDK the same year. The Wireless Display Adapter, released in 2014, was Microsoft's first hardware device to use embedded Linux.

In the beginning of 2015, Microsoft open sourced the Z3 Theorem Prover, a cross-platform satisfiability modulo theories (SMT) solver.{{Cite web|url=https://sdtimes.com/android/microsofts-visual-studio-timeline-and-z3-theorem-prover-google-cloud-launcher-facebooks-fresco-sd-times-news-digest-march-27-2015/|title=Microsoft's Visual Studio timeline and Z3 Theorem Prover, Google Cloud Launcher, Facebook's Fresco—SD Times news digest: March 27, 2015|date=March 27, 2015}}

Also in 2015, Microsoft co-founded the Node.js Foundation[https://www.onmsft.com/news/microsoft-moves-others-help-create-nodejs-foundation Microsoft moves, with others, to help create the Node.js Foundation] and joined the R Foundation. After completing the acquisition of Revolution Analytics in 2015,{{cite web|last1= Sirosh|first1= Joseph|title= Microsoft Closes Acquisition of Revolution Analytics|url= http://blogs.technet.com/b/machinelearning/archive/2015/04/06/microsoft-closes-acquisition-of-revolution-analytics.aspx|website= blogs.technet.com|publisher= Microsoft|access-date=2018-09-20}} Microsoft integrated the open source R programming language into SQL Server 2016, SQL Server 2017, SQL Server 2019, Power BI, Azure SQL Managed Instance, Azure Cortana Intelligence, Microsoft ML Server and Visual Studio 2017.{{Cite news|url=https://blogs.msdn.microsoft.com/visualstudio/2016/03/22/introducing-r-tools-for-visual-studio-3/|title=Introducing R Tools for Visual Studio|access-date=2018-09-20|language=en-US}}

The same year, Microsoft also open sourced Matter Center, Microsoft's legal practice management software and also Chakra, the Microsoft Edge JavaScript engine at the time. Also in 2015, Microsoft released Windows 10 with native support for the open-source AllJoyn framework, which means that any Windows 10 device can control any AllJoyn-aware Internet of Things (IoT) device in the network.{{cite web|url=https://www.techrepublic.com/article/windows-10-supports-alljoyn-making-the-internet-of-things-possible/|title=Windows 10 supports AllJoyn making the Internet of Things possible|last=Kaelin|first=Mark|date=17 June 2015|website=TechRepublic|access-date=5 December 2020}} Microsoft has been developing AllJoyn support and contributing code upstream since 2014.

Microsoft opened the keynote speech at All Things Open in 2015 by stating that:

{{blockquote|Microsoft's approach to open today is: Enable, integrate, release, and contribute.|Mark Russinovich, CTO of Microsoft Azure{{Cite web|url=https://www.zdnet.com/article/mark-russinovich-the-microsoft-azure-cloud-and-open-source/|title=Microsoft's Mark Russinovich to Linux faithful: Send us your resumes|first=Steven J.|last=Vaughan-Nichols|website=ZDNet}}}}

In August 2015, Microsoft released WinObjC, also known as Windows Bridge for iOS, an open-source middleware toolkit that allows iOS apps developed in Objective-C to be ported to Windows 10.{{cite web|url=http://www.pcworld.com/article/2960526/software-development/microsoft-releases-ios-to-windows-app-maker-windows-bridge-to-open-source.html|title=Microsoft releases iOS-to-Windows app maker Windows Bridge to open source|last=Hachman|first=Mark|website=PC World|publisher=IDG|date=August 6, 2015|access-date=October 9, 2015}}{{cite web|url=http://www.anandtech.com/show/9205/microsoft-demonstrates-android-and-ios-applications-running-on-windows-10|title=Microsoft Demonstrates Android and iOS Applications Running On Windows 10|last=Chester|first=Brandon|website=Anandtech|publisher=Purch Inc.|date=April 29, 2015|access-date=October 9, 2015}}{{cite web|url=https://venturebeat.com/2015/05/01/everything-you-need-to-know-about-porting-android-and-ios-apps-to-windows-10/|title=Everything you need to know about porting Android and iOS apps to Windows 10|last=Protalinski|first=Emil|website=VentureBeat|date=May 1, 2015|access-date=October 9, 2015}} On November 18, 2015, Visual Studio Code was released under the proprietary Microsoft License and a subset of its source code was posted to GitHub under the MIT License.{{cite news|title=Visual Studio now supports debugging Linux apps; Code editor now open source|url=https://arstechnica.com/information-technology/2015/11/visual-studio-now-supports-debugging-linux-apps-code-editor-now-open-source/|access-date=18 November 2015|work=Ars Technica}}

File:Number of open source contributors by company.png

In January 2016, Microsoft became Gold Sponsor of SCALE 14x – the fourteenth annual Southern California Linux Expo, a major convention.{{Cite web|url=https://www.socallinuxexpo.org/scale/14x|title=SCALE 14x | SCALE 14x|website=www.socallinuxexpo.org}}

When Microsoft acquired Xamarin and LinkedIn in 2016, it relicensed the Mono framework under MIT License and continued maintaining the Kafka stream-processing software platform as open source. Also in 2016, Microsoft introduced the Windows Subsystem for Linux, which lets Linux applications run on the Windows operating system. The company invested in Linux server technology and Linux development to promote cross-platform compatibility and collaboration with open source companies and communities, culminating with Microsoft's platinum sponsorship of the Linux Foundation and seat on its board of directors.{{sfn|Radits|2019|p=33}}

Microsoft released SQL Server and the now open source PowerShell for Linux. Also, Microsoft began porting Sysinternals tools, including ProcDump and ProcMon, to Linux.{{cite web|url=https://www.zdnet.com/article/microsoft-working-on-porting-sysinternals-to-linux/|title=Microsoft working on porting Sysinternals to Linux|last=Cimpanu|first=Catalin|date=5 November 2018|website=ZDNet|publisher=CBS Interactive|access-date=5 November 2018}} R Tools for Visual Studio were released under Apache License 2.0 in March 2016.

In March 2016, Ballmer changed his stance on Linux, saying that he supports his successor Satya Nadella's open source commitments. He maintained that his comments in 2001 were right at the time but that times have changed.{{cite web|url=https://www.informationweek.com/software/ballmer-linux-no-longer-a-cancer--/d/d-id/1324661|title=Ballmer: Linux No Longer A Cancer - InformationWeek|date=March 11, 2016 |publisher=}}{{cite web|url=http://www.silicon.co.uk/software/open-source/steve-ballmer-linux-microsoft-187802?inf_by=5a088e9d671db8d83d8b4959|title=Steve Ballmer: Linux Is No Longer 'A Cancer'|date=March 11, 2016|publisher=}}

Commentators have noted the adoption of open source and the change of strategy at Microsoft:{{Cite web|url=https://www.zdnet.com/article/linux-and-open-source-have-won-get-over-it/|title=Linux and open source have won, get over it|first=Steven J.|last=Vaughan-Nichols|website=ZDNet}}

{{blockquote|The company has become an enthusiastic supporter of Linux and of open source and a very active member of many important projects.|Jim Zemlin, Executive Director of The Linux Foundation{{Cite web|url=https://www.computerworld.com/article/3144063/open-source-has-won-and-microsoft-has-surrendered.html|title=Open source has won, and Microsoft has surrendered|first=Steven J.|last=Vaughan-Nichols|date=November 28, 2016|website=Computerworld}}}}

At EclipseCon in March 2016, Microsoft announced that the company is joining the Eclipse Foundation as a Solutions Member.{{cite web|url=https://www.neowin.net/news/microsoft-joins-eclipse-foundation-and-brings-more-tools-to-community/|title=Microsoft joins Eclipse Foundation and brings more tools to community|last=Hill|first=Paul|date=8 March 2013|website=Neowin|access-date=3 August 2021}}

The BitFunnel search engine indexing algorithm and various components of the Microsoft Bing search engine were made open source by Microsoft in 2016.{{Cite web|url=https://www.infoworld.com/article/3116080/microsoft-open-sources-bing-components-for-fast-code-compilation.html|title=Microsoft open-sources Bing components for fast code compilation|first=Serdar|last=Yegulalp|date=September 6, 2016|website=InfoWorld}}{{Cite web|last=Verma|first=Arpit|date=2016-09-07|title=Microsoft Open Sources Major Components Of Bing Search Engine, Here's Why It Matters|url=https://fossbytes.com/microsoft-working-open-source-search-components-used-power-bing/|access-date=2020-06-12|website=Fossbytes|language=en-US}} vcpkg, a cross-platform open source package manager, was released in September 2016.{{Cite web|url=https://sdtimes.com/android/yelp-launches-yelp-fusion-microsoft-creates-vcpkg-tool-new-touch-sense-sdk-android-developers-sd-times-news-digest-sept-20-2016/|title=Yelp launches Yelp Fusion, Microsoft creates Vcpkg tool, and the new Touch Sense SDK for Android developers|date=September 20, 2016|website=SD Times}}

Microsoft joined the Open Source Initiative, the Cloud Native Computing Foundation, and the MariaDB Foundation in 2017. The Open Source Initiative, formerly a target of Microsoft, used the occasion of Microsoft's sponsorship as a milestone for open source software's widespread acceptance.

The Debian-based SONiC network operating system was open sourced by Microsoft in 2017.{{Cite web|first=Michael|last=Cooney|url=https://www.networkworld.com/article/3584918/meet-sonic-the-new-nos-definitely-not-the-same-as-the-old-nos.html|title=Meet SONiC, the new NOS (definitely not the same as the old NOS)|date=October 8, 2020|website=NETWORKWORLD}}

Also the same year, the Windows development was moved to Git and Microsoft open sourced the Git Virtual File System (GVFS) developed for that purpose.{{Cite web|url=https://devblogs.microsoft.com/bharry/scaling-git-and-some-back-story/|title=Scaling Git (and some back story)|date=February 3, 2017|website=Brian Harry's Blog}}{{Cite web|url=https://www.infoq.com/news/2017/02/GVFS/|title=How Microsoft Solved Git's Problem with Large Repositories|website=InfoQ}} Other contributions to Git include a number of performance improvements useful when working with large repositories.{{Cite web|url=https://devblogs.microsoft.com/devops/microsofts-performance-contributions-to-git-in-2017/|title=Microsoft's Performance Contributions to Git in 2017|date=January 11, 2018|website=Azure DevOps Blog}}{{Cite web|url=https://www.welcometothejungle.com/en/articles/git-merge-2019-recap|title=Git Merge 2019: A Recap|website=www.welcometothejungle.com}} Microsoft opened the Microsoft Store to open source applications and gave the keynote speech at the Open Source Summit North America 2017 in Los Angeles.

In 2018, the Microsoft CTO of Data spoke with ZDNet about the growing importance of open source stating that:

{{blockquote|We meet customers where they are, and in particular if you want Linux we'll give you Linux; if you want MySQL, well we'll give you MySQL; you want NoSQL well we'll give you NoSQL -- that means you need to be part of open source; open source by nature is a community thing.|Raghu Ramakrishnan, Microsoft CTO of Data{{Cite web|url=https://www.zdnet.com/article/why-open-source-is-so-important-to-microsoft/|title=Why open source is so important to Microsoft|first=Asha|last=Barbaschow|date=February 28, 2018|website=ZDNet|access-date=July 17, 2021}}}}

Microsoft became Platinum Sponsor and delivered the keynote of the 2018 Southern California Linux Expo – the largest community-run open-source and free software conference in North America.{{Cite web|url=https://www.socallinuxexpo.org/scale/16x|title=SCALE 16x | 16x|website=www.socallinuxexpo.org}}{{sfn|Radits|2019|p=34}}

Microsoft developed Linux-based operating systems for use with its Azure cloud services. Azure Cloud Switch supports the Azure infrastructure and is based on open source and proprietary technology, and Azure Sphere powers Internet of things devices. As part of its announcement, Microsoft acknowledged Linux's role in small devices where the full Windows operating system would be unnecessary.{{sfn|Radits|2019|p=34}}

File:20060424 Nat Friedman.jpg, former CEO of Microsoft's GitHub subsidiary, the largest host of source code in the world]]

File:Lc3 2018 (263682137).jpeg ecosystem including Helm speaking at LinuxCon 2018 in China.{{Cite web|url=https://www.linuxfoundation.org/en/blog/michelle-noorali-helping-users-and-developers-consume-open-source/|title=Michelle Noorali: Helping Users and Developers Consume Open Source|date=August 2, 2018}} Noorali serves on the Kubernetes Steering Committee.{{Cite web|url=https://events19.lfasiallc.com/events/lc3-2018/program/featured-speakers/|title=Featured Speakers - LinuxCon + ContainerCon + CloudOpen China 2018}}]]

File:Lc3 2018 (263682189).jpeg booth at LinuxCon 2018 in Beijing, China]]

Also in 2018, Microsoft acquired GitHub, the largest host for open source project infrastructure. Microsoft is among the site's most active contributors and the site hosts the source code for Microsoft's Visual Studio Code and .NET runtime system. The company, though, has received some criticism for only providing limited returns to the Linux community, since the GPL license lets Microsoft modify Linux source code for internal use without sharing those changes.{{sfn|Radits|2019|p=35}}

In 2018, Microsoft included OpenSSH, tar, and curl commands in Windows.{{Cite web |url=https://devblogs.microsoft.com/powershell/openssh-for-windows-update/ |title= OpenSSH for Windows Update |date=19 October 2015 |access-date=2020-10-18}}{{Cite web |url=https://devblogs.microsoft.com/commandline/tar-and-curl-come-to-windows/ |title= Tar and Curl Come to Windows! |date=18 January 2018 |access-date=2020-11-29}} Also, Microsoft released Windows Calculator as open source under MIT License on GitHub.{{Cite web|url=https://www.zdnet.com/article/microsoft-is-open-sourcing-windows-calculator-on-github/|title=Microsoft is open-sourcing Windows Calculator on GitHub|last=Foley|first=Mary Jo|authorlink=Mary Jo Foley|date=6 March 2019|website=ZDNet|access-date=2020-10-18}}

Since 2018, Microsoft has been a sponsor of the AdoptOpenJDK project. It is a drop-in replacement for Oracle's Java/JDK.{{Cite web|last=Foley|first=Mary Jo|date=2020-06-24|title=Microsoft completes phase one of porting OpenJDK for Windows 10 on ARM devices|url=https://www.zdnet.com/article/microsoft-completes-phase-one-of-porting-openjdk-for-windows-10-on-arm-devices/|access-date=2021-04-13|website=ZDNet|language=en-US}}

In April 2018, Microsoft released the Windows 3.x/Windows NT File Manager source code licensed under the MIT License.{{cite web |url=https://techcrunch.com/2018/04/09/90s-kids-rejoice-microsoft-releases-the-original-windows-3-0-file-manager-source-code/ |title=90s kids rejoice! Microsoft releases the original Windows 3.0 File Manager source code |author=John Biggs |date=April 9, 2018 |publisher=TechCrunch |access-date=15 April 2018}}{{cite web |url=https://www.theverge.com/2018/4/9/17214586/microsoft-windows-file-manager-windows-10-app-download |title=Microsoft open-sources original File Manager from the '90s so it can run on Windows 10 - The Verge |author=Tom Warren |publisher=The Verge |access-date=7 April 2018}} In August 2018, Microsoft added support for the open source Python programming language to Power BI.{{Cite web|url=https://www.infoworld.com/article/3299704/microsoft-adds-python-support-to-power-bi.html|title=Microsoft adds Python support to Power BI|first=Serdar|last=Yegulalp|date=August 22, 2018|website=InfoWorld}} In October 2018, Microsoft joined the Open Invention Network{{Cite web |last1=Vaughan-Nichols |first1=Steven J. |title=Microsoft open-sources its patent portfolio |work=ZDNet |date=2018-10-10 |url=https://www.zdnet.com/article/microsoft-open-sources-its-entire-patent-portfolio/ |language=en |access-date=2019-04-21 |df=mdy-all}} and cross-licensed 60,000 patents with the open source community.{{Cite web|url=https://www.zdnet.com/article/what-does-microsoft-joining-the-open-invention-network-mean-for-you/|title=What does Microsoft joining the Open Invention Network mean for you?|first=Steven J.|last=Vaughan-Nichols|website=ZDNet}}{{Cite web |last1=Gartenberg |first1=Chaim |title=Microsoft makes its 60,000 patents open source to help Linux |work=The Verge |date=2018-10-10 |url=https://www.theverge.com/2018/10/10/17959978/microsoft-makes-its-60000-patents-open-source-to-help-linux |access-date=2019-04-21 |df=mdy-all}}

In 2019, Microsoft's Windows Subsystem for Linux 2 transitioned from an emulated Linux kernel to a full Linux kernel within a virtual machine, improving processor performance manifold. In-keeping with the GPL open source license, Microsoft will submit its kernel improvements for accommodation into the master, public release.{{Cite web |last1=Bright |first1=Peter |title=Windows 10 will soon ship with a full, open source, GPLed Linux kernel |work=Ars Technica |date=2019-05-06 |url=https://arstechnica.com/gadgets/2019/05/windows-10-will-soon-ship-with-a-full-open-source-gpled-linux-kernel/ |access-date=2019-05-07 |df=mdy-all }}

Also in 2019, Microsoft released Windows Terminal, PowerToys, and the Microsoft C++ Standard Library as open source and transitioned its Edge browser to use the open source Chromium as the basis.{{Cite web |last1=Warren |first1=Tom |title=Inside Microsoft's surprise decision to work with Google on its Edge browser |work=The Verge |date=2019-05-06 |url=https://www.theverge.com/2019/5/6/18527550/microsoft-chromium-edge-google-history-collaboration |access-date=2019-05-07 |df=mdy-all }} The Windows Console infrastructure was open-sourced under the MIT License alongside Windows Terminal.{{Cite web|url=https://devblogs.microsoft.com/commandline/introducing-windows-terminal/|title=Introducing Windows Terminal|last=Cinnamon|first=Kayla|date=May 6, 2019|website=Windows Command Line Tools For Developers|publisher=Microsoft|access-date=May 10, 2019}}

After publishing exFAT as an open specification, Microsoft contributed the patents to the Open Invention Network (OIN), and started upstreaming the device driver to the Linux kernel.

At Build 2019, Microsoft announced that it is open-sourcing its Quantum Development Kit, including its Q# compilers and simulators.{{Cite web|url=https://venturebeat.com/2019/05/06/microsoft-open-sourcing-quantum-development-kit/|title=Microsoft is open-sourcing its Quantum Development Kit|date=May 6, 2019}}

In December 2019, Microsoft released Microsoft Teams for Linux. This marked the first time Microsoft released an Office app for the Linux operating system. The app is available in native packages in .deb and .rpm formats.{{Cite web|url=https://www.theverge.com/2019/12/10/21004846/microsoft-office-linux-microsoft-teams-app-launch-public-preview|title=Microsoft's first Office app arrives on Linux|first=Tom|last=Warren|date=December 10, 2019|website=The Verge}} Also in December 2019, after JS Foundation and Node.js Foundation merged to form OpenJS Foundation, Microsoft contributed the popular cross-platform desktop application development tool Electron to OpenJS Foundation.{{Cite web|url=https://www.infoq.com/news/2020/01/electron-joins-openjs-foundation/|title=Electron Desktop JavaScript Framework Finds a New Home|website=InfoQ}}{{Cite web|url=https://openjsf.org/blog/2019/12/11/electron-joins-the-openjs-foundation/|title=Electron joins the OpenJS Foundation|date=December 11, 2019}}

Project Verona, a memory-safe research programming language, was open sourced in January 2020.{{Cite web|url=https://winbuzzer.com/2020/01/17/microsofts-rust-based-project-verona-reaches-open-source-on-github-xcxwbn/|title=Microsoft's Rust-Based Project Verona Reaches Open Source on GitHub|first=Luke|last=Jones|date=January 17, 2020|website=WinBuzzer}}{{Cite web|url=https://www.zdnet.com/article/microsoft-opens-up-rust-inspired-project-verona-programming-language-on-github/|title=Microsoft opens up Rust-inspired Project Verona programming language on GitHub|first=Liam|last=Tung|website=ZDNet}} Microsoft released DeepSpeed, an open source deep learning optimization library for PyTorch, in February 2020.{{Cite web|url=https://www.infoworld.com/article/3526449/microsoft-speeds-up-pytorch-with-deepspeed.html|title=Microsoft speeds up PyTorch with DeepSpeed|first=Serdar|last=Yegulalp|date=February 10, 2020|website=InfoWorld}}

In 2020, Microsoft open sourced the Java extension for Microsoft SQL Server, MsQuic (a Windows NT kernel library for the QUIC general-purpose transport layer network protocol),{{Cite web|url=https://www.zdnet.com/article/microsoft-open-sources-in-house-library-for-handling-quic-connections/|title=Microsoft open-sources in-house library for handling QUIC connections|first=Catalin|last=Cimpanu|website=ZDNet}} Project Petridish, a neural architecture search algorithm for deep learning,{{Cite web|url=https://www.infoq.com/news/2020/02/petridish-deep-learning/|title=Microsoft Open-Sources Project Petridish for Deep-Learning Optimization|website=InfoQ}} and the Fluid Framework for building distributed, real-time collaborative web applications.{{Cite web |last1=Tung |first1=Liam |title=Microsoft's new Fluid Framework: Now it's open-sourced on GitHub |work=ZDNet |date=2020-09-10 |url=https://www.zdnet.com/article/microsofts-new-fluid-framework-now-its-open-sourced-on-github/ |language=en |access-date=2020-09-20 |df=mdy-all}} Microsoft also released the Linux-based Azure Sphere operating system.

In March 2020, Microsoft acquired npm, the open source Node package manager. It is the world’s largest software registry with more than 1.3 million packages that have 75 billion downloads a month.{{Cite web|url=https://itsfoss.com/microsoft-npm-acquisition/|title=With npm, Microsoft Now Owns the Largest Software Registry in the World|first=Abhishek|last=Prakash|date=March 17, 2020 }}{{Cite web|url=https://github.blog/2020-03-16-npm-is-joining-github/|title=npm is joining GitHub|date=March 16, 2020}} Also in March 2020, Microsoft together with researchers and leaders from the Allen Institute for AI, the Chan Zuckerberg Initiative, the Georgetown University's Center for Security and Emerging Technhology, and the National Library of Medicine released CORD-19, a public dataset of academic articles about COVID-19 and research related to the COVID-19 pandemic.[https://mspoweruser.com/microsoft-help-create-29000-article-covid-19-open-research-dataset-to-help-ai-save-us/ Microsoft help create 29,000 article COVID-19 Open Research Dataset to help AI save us] The dataset is created through the use of text mining of the current research literature.{{Cite web|title=Call to Action to the Tech Community on New Machine Readable COVID-19 Dataset|url=https://trumpwhitehouse.archives.gov/briefings-statements/call-action-tech-community-new-machine-readable-covid-19-dataset/|access-date=2020-10-13|via=National Archives|work=whitehouse.gov|language=en-US}}{{Cite web|title=NLM Leverages Data, Text Mining to Sharpen COVID-19 Research Databases|url=https://governmentciomedia.com/nlm-leverages-data-text-mining-sharpen-covid-19-research-databases|access-date=2020-10-13|website=governmentciomedia.com|date=May 11, 2020 |language=en}}

After exploring different alternative options and talking with various well-known commercial and open source package manager teams including Chocolatey, Scoop, Ninite and others such as AppGet, Npackd and the PowerShell based OneGet package manager-manager, Microsoft decided to develop and release the open source Windows Package Manager in 2020.{{Cite web|title=Windows Package Manager Preview |date=May 19, 2020 |url=https://devblogs.microsoft.com/commandline/windows-package-manager-preview/ |language=en |access-date=2020-11-29}}

Microsoft was one of the silver sponsors for the X.Org Developer’s Conference 2020 (XDC2020). Microsoft had multiple developers presenting on the opening day.{{Cite web|url=https://www.phoronix.com/scan.php?page=news_item&px=Microsoft-XDC-2020|title=Microsoft Has A Large Presence At This Year's X.Org Conference - Phoronix|website=www.phoronix.com}}

Microsoft completed the first phase of porting the Java OpenJDK for Windows 10 on ARM devices in June 2020.

In August 2020, Microsoft became founding member of the Open Source Security Foundation (OpenSSF), a cross-industry forum for a collaborative effort to improve open source software security.[https://www.infoq.com/news/2020/08/open-source-security-foundation/ Google, Microsoft, GitHub, and Others Join the Open Source Security Foundation][https://www.zdnet.com/article/uniting-for-better-open-source-security-the-open-source-security-foundation/ Uniting for better open-source security: The Open Source Security Foundation | ZDNet]

In September 2020, Microsoft released the Surface Duo, an Android-based smartphone with a Linux kernel.{{Cite web |last=Warren |first=Tom |date=13 August 2020 |title=Microsoft Surface Duo Arrives on September 10th for $1399 |url=https://www.theverge.com/2020/8/12/21364633/microsoft-surface-duo-release-date-pricing-features-specs |website=TheVerge |language=en}} The same month, Microsoft released OneFuzz, a self-hosted fuzzing-as-a-service platform that automates the detection of software bugs.{{Cite web|url=https://www.zdnet.com/article/microsoft-windows-10-is-hardened-with-these-fuzzing-security-tools-now-theyre-open-source/|title=Microsoft: Windows 10 is hardened with these fuzzing security tools – now they're open source|date=September 15, 2020|website=ZDNet}} It supports Windows and Linux.{{Cite web|url=https://www.infoworld.com/article/3575600/microsoft-open-sources-fuzzing-test-framework.html|title=Microsoft open-sources fuzzing test framework|date=September 17, 2020|website=InfoWorld}}

Microsoft is a major contributor to the Chromium project with the highest percentage of all non-Google contributors coming from Microsoft (35.2%). The company has contributed 29.4% of all non-Google commits to the source code in 2020.{{cite web|title=Google gets web allies by letting outsiders help build Chrome's foundation|url=https://www.cnet.com/news/google-gets-web-allies-by-letting-outsiders-help-build-chromes-foundation/|access-date=23 November 2020}} CBL-Mariner, a cloud infrastructure operating system based on Linux and developed by the Linux Systems Group at Microsoft for its edge network services and as part of its Microsoft Azure cloud infrastructure was open sourced in 2020.{{Cite web|first=Simon|last=Bisson|url=https://www.infoworld.com/article/3596347/microsoft-adds-a-new-linux-cbl-mariner.html|title=Microsoft adds a new Linux: CBL-Mariner|date=November 10, 2020|website=InfoWorld}}{{Cite web|first=Mary Jo|last=Foley|url=https://www.zdnet.com/article/cbl-mariner-microsofts-internal-linux-distribution-for-azure-first-party-services-and-edge-appliances/|title=CBL-Mariner: Microsoft's internal Linux distribution for Azure first-party services and edge appliances|date=November 11, 2020|website=ZDNet}}

In February 2021, Microsoft made the source code for its Extensible Storage Engine (ESE) available on GitHub under MIT License.{{Cite web|last=Speed|first=Richard|url=https://www.theregister.com/2021/02/01/ese_github/|title=Microsoft's Extensible Storage Engine (JET Blue) source code arrives on GitHub – sadly comments not included|date=February 1, 2021|website=The Register}} Also in February 2021, Microsoft, together with four other founding companies (AWS, Huawei, Google, and Mozilla) formed the Rust Foundation as an independent non-profit organization to steward the open source Rust programming language and ecosystem.{{Cite web|last=|first=|date=2021-02-08|title=Rust Foundation|url=https://foundation.rust-lang.org/|access-date=2021-02-09|website=foundation.rust-lang.org|language=en}}{{Cite web|last=|first=|date=2021-02-09|title=Mozilla Welcomes the Rust Foundation|url=https://blog.mozilla.org/blog/2021/02/08/mozilla-welcomes-the-rust-foundation|access-date=2021-02-09|website=Mozilla Blog|language=en-US}} In March 2021, Microsoft became founding member of the new Eclipse Adoptium Working Group whose goal is to promote free, open source Java runtimes.{{Cite web|last=Anderson|first=Tim|date=2021-03-23|title=Total Eclipse team's new start: New Adoptium working group will promote free open source Java runtimes|url=https://www.theregister.com/2021/03/23/new_adoptium_working_group_will/|access-date=2021-06-03|website=The Register}} Microsoft released a preview of the Microsoft Build of OpenJDK in April 2021. It is available for x64 server and desktop editions of Windows, as well as on Linux and macOS. The company provides long-term support for this distribution of the OpenJDK.{{Cite web|last=Foley|first=Mary Jo|date=2021-04-06|title=Microsoft rolls out its OpenJDK preview release|url=https://www.zdnet.com/article/microsoft-rolls-out-its-openjdk-preview-release/|access-date=2021-04-13|website=ZDNet|language=en-US}} In April 2021, Microsoft also released a Windows 10 test build that includes the ability to run Linux graphical user interface (GUI) apps using Windows Subsystem for Linux 2.{{Cite news|last=Foley|first=Mary Jo|date=2021-04-21|url=https://www.zdnet.com/article/new-windows-10-test-build-adds-first-preview-of-linux-gui-apps-on-wsl/|title=New Windows 10 test build adds first preview of Linux GUI apps on WSL|access-date=2021-04-23|website=ZDNet|language=en-US}} In the following month, Microsoft launched an open source project to make the Berkeley Packet Filter work on Windows.{{cite web|url=https://www.theregister.com/2021/05/11/microsoft_linux_ebpf/|title=Microsoft embraces Linux kernel's eBPF super-tool, extends it for Windows|date=2011-05-11|publisher=The Register}}

At the Windows 11 announcement event in June 2021, Microsoft showcased the new Windows Subsystem for Android (WSA) that will enable support for the Android Open Source Project (AOSP) and will allow users to run Android apps on their Windows desktop.{{cite web|last=Parmar|first=Mayank|date=2021-06-27|url=https://www.windowslatest.com/2021/06/27/microsoft-confirms-android-apps-will-run-on-all-windows-11-pcs/|title=Microsoft confirms Android apps will run on all Windows 11 PCs|access-date=2021-06-28|publisher=Windows Latest}}

In August 2021, Microsoft announced that it is expanding its partnership to become a Strategic Member at the Eclipse Foundation.{{cite web|url=https://www.neowin.net/news/microsoft-is-now-a-strategic-member-of-the-eclipse-foundation/|title=Microsoft is now a Strategic Member of the Eclipse Foundation|last=Jawad|first=Usama|date=3 August 2021|website=Neowin|access-date=3 August 2021}}

Microsoft released the source code of 3D Movie Maker under the MIT License in May 2022,{{cite web |title=microsoft / Microsoft-3D-Movie-Maker |url=https://github.com/microsoft/Microsoft-3D-Movie-Maker |website=Github |access-date=4 May 2022}}{{Cite tweet|last=Hanselman|first=Scott|user=shanselman|number=1521698902579159040|title=Hey friends - we've open sourced the code to 1995's Microsoft 3D Movie Maker}} following a request by the Twitter user Foone a month earlier.{{Cite tweet|user=Foone|number=1511808848729804803|title=hey @Microsoft give me the source code to 3D Movie Maker. You released it in 1995 and I want to expand and extend it.}} Also in May, Microsoft joined the XDP community and released a new open-source Express Data Path interface for Windows.{{cite web|url=https://www.neowin.net/news/microsoft-brings-linux-xdp-project-to-windows/|title=Microsoft brings Linux XDP project to Windows|last=Jawad|first=Usama|date=25 May 2022|website=Neowin|access-date=26 May 2022}}{{cite web|url=https://cloud7.news/development/microsoft-introduced-open-source-xdp-for-windows/|title=Microsoft introduced open-source XDP for Windows|last=Yasar|first=Erdem|date=25 May 2022|website=cloud7|access-date=26 May 2022}}

In August 2022, Microsoft open sourced more than 1,500 of its 3D emoji to let creators remix and customize them. The library is available on Figma and GitHub.{{cite web|url=https://www.theverge.com/2022/8/10/23299527/microsoft-emoji-open-source-creators|title=Microsoft open sources its 3D emoji to let creators remix and customize them|last=Warren|first=Tom|date=10 August 2022|website=The Verge|access-date=14 August 2022}}

On May 18, 2025, Microsoft released Microsoft Edit, an open-source recreation of the MS-DOS Editor written in the Rust programming language for modern versions of Windows.{{cite web|url=https://www.theverge.com/news/669318/microsoft-edit-on-windows-command-line-text-editor|title=Microsoft’s Edit on Windows is a new command-line text editor|work=The Verge|date=19 May 2025|access-date=21 May 2025|author-last=Warren|author-first=Tom}}

Microsoft is either founding member, joining member, contributing member, and/or sponsor of a number of open source related organizations and initiatives. Examples include:

{{columns-list|colwidth=18em|

• .NET Foundation{{Cite web |last1=Lardinois |first1=Frederic |date=April 3, 2014 |title=Microsoft Launches .NET Foundation To Foster The .NET Open Source Ecosystem |url=https://techcrunch.com/2014/04/03/microsoft-launches-net-foundation-to-foster-the-net-open-source-ecosystem/ |website=TechCrunch |access-date=2020-10-18}}
• Alliance for Open Media{{Cite web|url=http://aomedia.org/about/|title=About|website=Alliance for Open Media}}
• Apache Software Foundation
• Bytecode Alliance{{Cite web|url=https://bytecodealliance.org/|title=Bytecode Alliance|website=Bytecode Alliance}}
• Cloud Native Computing Foundation{{Cite web|url=https://www.cncf.io/about/members/|title=Members|website=Cloud Native Computing Foundation}}
• CodePlex Foundation, later known as Outercurve Foundation
• Confidential Computing Consortium{{Cite web|url=https://confidentialcomputing.io/members/|title=Members}}
• Eclipse Adoptium Working Group{{Cite web|url=https://www.microsoft.com/openjdk|title=Microsoft Build of OpenJDK|website=Microsoft}}
• Eclipse Foundation{{Cite web|url=https://www.eclipse.org/membership/exploreMembership.php#tab-contributing|title=Explore Our Members | The Eclipse Foundation|first=Christopher|last=Guindon|website=www.eclipse.org}}
• F# Software Foundation{{Cite web |url=http://www.eweek.com/developer/f-foundation-taking-microsofts-f-language-to-a-higher-ground/ |title=F# Foundation: Taking Microsoft's F# Language to a Higher Ground (eWeek) |date=January 6, 2013 |access-date=2020-10-18}}
• Hyperledger{{Cite web|url=https://www.hyperledger.org/about/members|title=Supporting Members}}
• Linux Foundation
• MariaDB Foundation
• Node.js Foundation
• Open 3D Foundation{{Cite web|date=2022-05-12|title=O3D Foundation|url=https://o3d.foundation//|access-date=2022-07-23|website=O3D Foundation|language=en-US}}
• OpenAPI Initiative{{Cite web|url=https://www.openapis.org/membership/members|title=Current Members}}
• OpenBMC{{Cite web|url=https://www.openbmc.org/|title=Home|website=OpenBMC}}
• OpenChain{{Cite web|url=https://openchain.lfprojects.linuxfoundation.org/|title=Home|website=OpenChain}}
• Open Compute Project{{Cite web|url=https://www.opencompute.org/membership/membership-organizational-directory|title=Open Compute Project|website=Open Compute Project}}
• Open Connectivity Foundation{{Cite web|url=https://openconnectivity.org/foundation/membership-list/|title=OCF Membership List}}
• Open Container Initiative{{Cite web|url=https://opencontainers.org/|title=Open Container Initiative - Open Container Initiative|website=opencontainers.org}}
• Open Infrastructure Foundation{{Cite web|url=https://www.zdnet.com/article/microsoft-joins-open-infrastructure-foundation/|title=Microsoft joins Open Infrastructure Foundation|website=ZDNet|access-date=2021-09-10}}
• Open Invention Network{{Cite web|url=https://openinventionnetwork.com/directory-community/tags/united-states/|title=United States Archives}}
• OpenJS Foundation{{Cite web|url=https://openjsf.org/about/members/|title=Members}}
• Open Source Initiative
• Open Source Security Foundation{{Cite web|url=https://www.infoq.com/news/2020/08/open-source-security-foundation/|title=Google, Microsoft, GitHub, and Others Join the Open Source Security Foundation|website=InfoQ}}
• Open Web Foundation
• Outreachy{{Cite web|url=https://www.outreachy.org/|title=Outreachy | Internships Supporting Diversity in Tech|website=www.outreachy.org}}
• R Consortium{{Cite news |last=Machlis |first=Sharon |url=http://www.computerworld.com/article/3123783/enterprise-applications/esri-joins-r-consortium.html |title=Esri joins the R Consortium |work=Computerworld |access-date=2020-10-18 |language=en}}
• R Foundation
• Rust Foundation{{Cite web|url=https://www.neowin.net/news/rust-foundation-formed-to-manage-namesake-language|title=Rust Foundation formed to manage namesake language|website=Neowin|access-date=2021-02-08}}
• The Open Group[https://reports.opengroup.org/gold.shtml Open Group Gold Membership Report]
• Unified Patents Open Source Zone

}}

{{expand section|date=April 2019}}

• .NET – Managed code software framework for Windows, Linux, and macOS operating systems{{sfn|Radits|2019|p=33}}
• .NET Compiler Platform (Roslyn) – Compilers and code analysis APIs for C# and Visual Basic .NET programming languages
• .NET Gadgeteer – Rapid-prototyping standard for building small electronic devices
• .NET MAUI – A cross-platform UI toolkit
• .NET Micro Framework – .NET Framework platform for resource-constrained devices

File:Microsoft 3D Movie Maker 640x480.jpg]]

• 3D Movie Maker – A children's computer program developed by Microsoft Home's Microsoft Kids subsidiary for making films using 3D computer graphics
• AirSim – Simulator for drones, cars and other objects, built as a platform for AI research
• Allegiance – Multiplayer online game providing a mix of real-time strategy and player piloted space combat gameplay
• ASP.NET – It is a web application framework developed for building dynamic web applications and services.
• ASP.NET AJAX – It is a set of extensions for ASP.NET that enables developers to create asynchronous, interactive web applications.
• ASP.NET Core – It is an open-source, cross-platform framework developed for building modern web applications and services.
• ASP.NET MVC – It is a web application framework which follows the Model-View-Controller (MVC) architectural pattern.
• ASP.NET Razor – It is a markup syntax used in ASP.NET for creating web pages.
• ASP.NET Web Forms – It is a web application framework that allows developers to build dynamic websites by utilizing a component-based approach.

File:Atom screenshot v1.41.0.png text and source code editor with an open project on Windows 10]]

• Atom – Text and source code editor for macOS, Linux, and Microsoft Windows
• Babylon.js – A real time 3D engine using a JavaScript library for displaying 3D graphics in a web browser via HTML5
• BitFunnel – A signature-based search engine
• Blazor – Web framework that enables developers to create web apps using C# and HTML
• Bosque – Functional programming language{{Cite web |last1=Krill |first1=Paul |title=Microsoft aims for simplicity with Bosque programming language |work=InfoWorld |date=2019-04-18 |url=https://www.infoworld.com/article/3390197/microsoft-aims-for-simplicity-with-bosque-programming-language.html |language=en |access-date=2019-04-22 |df=mdy-all }}
• C++/WinRT – C++ library for Microsoft's Windows Runtime platform, designed to provide access to modern Windows APIs
• C# – General-purpose, multi-paradigm programming language encompassing strong typing, lexically scoped, imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines
• CBL-Mariner – Cloud infrastructure operating system based on Linux
• ChakraCore – JavaScript engine
• ChronoZoom – Project that visualizes time on the broadest possible scale from the Big Bang to the present day
• CLR Profiler – Memory profiler for the .NET Framework
• Conference XP – Video conferencing platform
• Dafny – Imperative compiled language that targets C# and supports formal specification through preconditions, postconditions, loop invariants and loop variants
• Dapr – Event-driven, portable runtime system designed to support cloud native and serverless computing
• DeepSpeed – Deep learning optimization library for PyTorch
• Detours – C++ library for intercepting, monitoring and instrumenting binary functions on Microsoft Windows

File:DiskSpd v2.0.21a 1115x624.png]]

• DiskSpd – Command-line tool for storage benchmarking that generates a variety of requests against computer files, partitions or storage devices
• Dynamic Language Runtime – Runtime that runs on top of the CLR and provides computer language services for dynamic languages
• eBPF on Windows – Register-based virtual machine designed to run a custom 64-bit RISC-like architecture via just-in-time compilation inside the kernel
• Extensible Storage Engine – An ISAM database engine that provides transacted data update and retrieval
• F* – Functional programming language inspired by ML and aimed at program verification
• F# – General purpose, strongly typed, multi-paradigm programming language that encompasses functional, imperative, and object-oriented programming methods
• File Manager – File manager for Microsoft Windows
• Fluid Framework – Platform for real-time collaboration across applications{{Cite web |last1=Tung |first1=Liam |title=Microsoft's new Fluid Framework: Now it's open-sourced on GitHub |work=ZDNet |date=2020-09-10 |url=https://www.zdnet.com/article/microsofts-new-fluid-framework-now-its-open-sourced-on-github/ |language=en |access-date=2020-09-20 |df=mdy-all }}{{Cite web |last1=Warren |first1=Tom |title=Microsoft's new Fluid Office document is Google Docs on steroids |work=The Verge |date=2020-05-19 |url=https://www.theverge.com/2020/5/19/21260005/microsoft-office-fluid-web-document-features-build |language=en |access-date=2020-05-20 |df=mdy-all }}
• [https://www.microsoft.com/en-us/research/project/fourqlib/ FourQlib] – Reference implementation of the FourQ elliptic curve
• GW-BASIC – Dialect of the BASIC programming language
• Microsoft C++ Standard Library – Implementation of the C++ Standard Library (also known as the STL){{Cite web|url=https://devblogs.microsoft.com/cppblog/open-sourcing-msvcs-stl/|title=Open Sourcing MSVC's STL|date=September 16, 2019|website=C++ Team Blog}}
• Microsoft Edit – TUI text editor

File:Monodevelop5.4.png IDE for Linux, macOS, and Windows]]

• Mixed Reality Toolkit – Software development kit (SDK) for the development of mixed reality (MR) and augmented reality (AR) software applications
• MonoDevelop – Integrated development environment for Linux, macOS, and Windows
• MSBuild – Build tool set for managed code as well as native C++ code
• MsQuic – Implementation of the IETF QUIC protocol
• Neural Network Intelligence – An AutoML toolkit
• npm – Package manager for the JavaScript programming language
• OneFuzz – Cross-platform fuzz testing framework
• Open Live Writer – Desktop blogging application
• Open Management Infrastructure – CIM management server
• Open XML SDK – set of managed code libraries to create and manipulate Office Open XML files programmatically
• Orleans – Cross-platform software framework for building scalable and robust distributed applications based on the .NET Framework
• P – Programming language for asynchronous event-driven programming and the IoT

File:PowerShell for Linux 6.0 Alpha 9 on Ubuntu.png for Linux on Ubuntu]]

• Power Fx – Low-code, general-purpose programming language for expressing logic across the Microsoft Power Platform
• PowerShell – Command-line shell and scripting language{{Cite web|url=https://docs.microsoft.com/en-us/powershell/scripting/overview|title=What is PowerShell? - PowerShell|website=docs.microsoft.com|date=June 28, 2023 }}
• Process Monitor – Tool that monitors and displays in real-time all file system activity
• ProcDump – Command-line application for creating crash dumps during a CPU spike{{Cite web|url=https://ss64.com/nt/procdump.html|title=ProcDump - Monitor CPU/processes - Windows CMD - SS64.com|website=ss64.com}}
• Project Mu – UEFI core used in Microsoft Surface and Hyper-V products
• Project Verona – Experimental memory-safe research programming language
• PowerToys for Windows 10 – System utilities for power users
• ReactiveX – A set of tools allowing imperative programming languages to operate on sequences of data regardless of whether the data is synchronous or asynchronous implementing reactive programming
• RecursiveExtractor – An archive file extraction library written in C#
• Sandcastle – Documentation generator
• StyleCop – Static code analysis tool that checks C# code for conformance to recommended coding styles and a subset of the .NET Framework design guidelines

File:Windows Terminal v1.0 1138x624.png]]

• Windows Terminal – Terminal emulator{{Cite web |last1=Bowden |first1=Zac |title=Microsoft's open source Windows Terminal app reaches stable release |work=Windows Central |date=2020-05-19 |url=https://www.windowscentral.com/microsofts-open-source-windows-terminal-app-reaches-stable-release |access-date=2020-05-20 |df=mdy-all }}{{Cite web |last1=Warren |first1=Tom |title=Microsoft unveils Windows Terminal, a new command line app for Windows |work=The Verge |date=2019-05-06 |url=https://www.theverge.com/2019/5/6/18527870/microsoft-windows-terminal-command-line-tool |language=en |access-date=2020-05-20 |df=mdy-all }}
• TypeScript – Programming language similar to JavaScript, among the most popular on GitHub{{Cite web |last1=Chan |first1=Rosalie |title=The 10 most popular programming languages, according to the Microsoft-owned GitHub |work=Business Insider |date=2019-11-09 |url=https://www.businessinsider.com/most-popular-programming-languages-github-2019-11 |access-date=2019-11-28 |df=mdy-all }}
• U-Prove – Cross-platform technology and accompanying SDK for user-centric identity management
• vcpkg – Cross-platform package manager used to simplify the acquisition and installation of third-party libraries
• VFS for Git – Virtual file system extension to the Git version control system
• Visual Basic .NET – Multi-paradigm, object-oriented programming language
• Visual Studio Code – Source code editor and debugger for Windows, Linux and macOS,{{sfn|Radits|2019|p=35}} and GitHub's top open source project{{r|top languages 2019}}
• VoTT (Visual Object Tagging Tool) – Electron app for image annotation and labeling

File:Screen-vowpal-wabbit.png]]

• Vowpal Wabbit – online interactive machine learning system library and program
• WikiBhasha – Multi-lingual content creation application for the Wikipedia online encyclopedia
• Windows Calculator – Software calculator{{Cite web |last1=Warren |first1=Tom |title=Microsoft open-sources its Windows calculator on GitHub |work=The Verge |date=2019-03-06 |url=https://www.theverge.com/2019/3/6/18253474/microsoft-windows-calculator-open-source-github |access-date=2019-04-21 |df=mdy-all }}{{Cite web |last1=Archambault |first1=Michael |title=Microsoft Continues Open-Source Effort, Releases Calculator Code |work=Digital Trends |date=2019-03-06 |url=https://www.digitaltrends.com/computing/microsoft-open-source-windows-calculator/ |language=en |access-date=2019-04-21 |df=mdy-all }}
• Windows Communication Foundation – runtime and a set of APIs for building connected, service-oriented applications
• Windows Console – Terminal emulator
• Windows Driver Frameworks – Tools and libraries that aid in the creation of device drivers for Microsoft Windows
• Windows Forms – Graphical user interface (GUI) class library

File:Windows Package Manager v0.1.41331 Preview 1115x624.png]]

• Windows Package Manager – Package manager for Windows 10
• Windows Presentation Foundation – Graphical subsystem (similar to WinForms) for rendering user interfaces in Windows-based applications
• Windows Subsystem for Linux – Windows component that allows a GNU/Linux environment to be used from within Windows.
• Windows Template Library – Object-oriented C++ template library for Win32 development
• Windows UI Library – Set of UI controls and features for the Universal Windows Platform (UWP)
• WinJS – JavaScript library for cross-platform app development
• WinObjC – Middleware toolkit that allows iOS apps developed in Objective-C to be ported to Windows 10
• WiX (Windows Installer XML Toolset) – Toolset for building Windows Installer packages from XML
• WorldWide Telescope – Astronomy software

File:XML Notepad 2007.png XML editor]]

• XDP for Windows – Interface used to accelerate networking by bypassing most of the OS networking stack
• XML Notepad – XML editor
• XSP – Standalone web server written in C# that hosts ASP.NET for Unix-like operating systems
• xUnit.net – Unit testing tool for the .NET Framework
• Z3 Theorem Prover – Cross-platform satisfiability modulo theories (SMT) solver

{{Portal|Free and open-source software}}

• Free software movement
• History of free and open-source software
• Timeline of free and open-source software
• Comparison of open-source and closed-source software
• Business models for open-source software

{{Reflist}}

{{refbegin}}

• {{Cite book |last1=Radits |first1=Markus |title=A Business Ecology Perspective on Community-Driven Open Source: The Case of the Free and Open Source Content Management System Joomla |date=2019-01-25 |language=en |isbn=978-91-7685-305-4 |publisher=Linköping University Electronic Press |df=mdy-all }}
• {{Cite web |last1=Bright |first1=Peter |title=Microsoft: The open source company |work=Ars Technica |date=2019-05-10 |url=https://arstechnica.com/gadgets/2019/05/microsoft-the-open-source-company/ |access-date=2019-05-11 |df=mdy-all }}
• {{Cite news |last1=Hayes |first1=Frank |title=The Microsoft Way |work=Computerworld |volume=35 |issue=12 |page=78 |date=2001-03-19 |url=https://books.google.com/books?id=dFT5Vb1soN0C&pg=PA78 |language=en |issn=0010-4841 |df=mdy-all }}
• {{Cite book|first=Satya|last=Nadella|year=2017|title=Hit Refresh: The Quest to Rediscover Microsoft's Soul and Imagine a Better Future for Everyone|publisher=Harper Business|isbn=978-0062652508}}
• {{Cite news |last1=Ovide |first1=Shira |title=Microsoft Dips Further Into Open-Source Software |work=Wall Street Journal |date=2012-04-16 |url=https://www.wsj.com/articles/SB10001424052702304432704577347783238850756 |language=en-US |issn=0099-9660 |df=mdy-all }}
• {{Cite web |last1=Vaughan-Nichols |first1=Steven J. |title=Why Microsoft loves Linux |work=ZDNet |date=2014-10-29 |url=https://www.zdnet.com/article/why-microsoft-loves-linux/ |language=en |access-date=2019-04-21 |df=mdy-all }}
• {{Cite web |last1=Vaughan-Nichols |first1=Steven J. |title=Microsoft: The open-source company |work=ZDNet |date=2015-01-26 |url=https://www.zdnet.com/article/microsoft-the-open-source-company/ |language=en |access-date=2019-12-31 |df=mdy-all }}
• {{Cite web |last1=Vaughan-Nichols |first1=Steven J. |title=Why Microsoft is turning into an open-source company |work=ZDNet |date=2016-06-09 |url=https://www.zdnet.com/article/why-microsoft-is-turning-into-an-open-source-company/ |language=en |access-date=2019-04-21 |df=mdy-all }}
• {{Cite web |last1=Vaughan-Nichols |first1=Steven J. |title=Linux and open-source rules: 2019's five biggest stories show why |work=ZDNet |date=2019-12-30 |url=https://www.zdnet.com/article/2019s-five-biggest-linux-and-open-source-stories/ |language=en |access-date=2019-12-31 |df=mdy-all }}
• {{Cite web |last1=Warren |first1=Tom |title=How Microsoft learned from the past to redesign its future |work=The Verge |date=2019-04-29 |url=https://www.theverge.com/2019/4/29/18515776/microsoft-design-open-fluent-prototypes-history |access-date=2019-04-30 |df=mdy-all }}
• {{Cite web |last1=Warren |first1=Tom |title=Microsoft: we were wrong about open source |work=The Verge |date=2020-05-18 |url=https://www.theverge.com/2020/5/18/21262103/microsoft-open-source-linux-history-wrong-statement |language=en |access-date=2020-05-20 |df=mdy-all }}
• {{Cite web |last1=Warren |first1=Tom |title=Microsoft angers the .NET open source community with a controversial decision |work=The Verge |date=2021-10-22 |url=https://www.theverge.com/2021/10/22/22740701/microsoft-dotnet-hot-reload-removal-decision-open-source |language=en |access-date=2021-10-23 |df=mdy-all }}

{{refend}}

• [https://opensource.microsoft.com/ Open source releases from Microsoft]

{{Microsoft}}

{{Microsoft FOSS}}

Open source

Category:History of free and open-source software