View source for MIT License

{{short description|Permissive free software license}}
{{Use American English|date=March 2021}}
{{Use mdy dates|date=March 2021}}
{{Infobox software license
| name = MIT License
| image = [[File:MIT Logo New.svg|155px]]
| author = <!-- An author is always a person. Something more clever than "Massachusetts Institute of Technology", please! -->
| copyright = [[Massachusetts Institute of Technology]]
| spdx = MIT<br />(see list for more)<ref name="SPDX License List" />
| OSI approved = Yes<ref name="osi-licenses">{{Cite web |url=https://opensource.org/licenses/alphabetical |title=Licenses by Name |date=n.d. |website=[[Open Source Initiative]] |access-date=2017-07-20 |archive-url=https://web.archive.org/web/20170720141629/https://opensource.org/licenses/alphabetical |url-status=live |archive-date=2017-07-20 |quote=The following licenses have been approved by the OSI. ...&nbsp;MIT License (MIT)&nbsp;...}}</ref>
| Debian approved = Yes<ref name="dfsg-licenses">{{Cite web |url=https://www.debian.org/legal/licenses/ |title=License information |date=1997–2017 |publication-date=2017-07-12 |website=The [[Debian Project]] |publisher=[[Software in the Public Interest]] |access-date=2017-07-20 |archive-url=https://web.archive.org/web/20170720142826/https://www.debian.org/legal/licenses/ |url-status=live |archive-date=2017-07-20 |quote=This page presents the opinion of some debian-legal contributors on how certain licenses follow the Debian Free Software Guidelines (DFSG).&nbsp;... Licenses currently found in Debian main include: ...&nbsp;Expat/MIT-style licenses&nbsp;...}}</ref>
| Free Software = Yes<ref name="gnu-license-list-expat">{{Cite web |url=https://www.gnu.org/licenses/license-list.en.html#Expat |title=Various Licenses and Comments about Them |date=2014–2017 |publication-date=2017-04-04 |website=The [[GNU Project]] |publisher=[[Free Software Foundation]] |at=Expat License |access-date=2017-07-20 |archive-url=https://web.archive.org/web/20170720140022/https://www.gnu.org/licenses/license-list.en.html |url-status=live |archive-date=2017-07-20 |quote=This is a lax, permissive non-copyleft free software license, compatible with the GNU GPL. It is sometimes ambiguously referred to as the MIT License.}}</ref><ref name="gnu-license-list-x11">{{Cite web |url=https://www.gnu.org/licenses/license-list.en.html#X11License |title=Various Licenses and Comments about Them |date=2014–2017 |publication-date=2017-04-04 |website=The [[GNU Project]] |publisher=[[Free Software Foundation]] |at=X11 License |access-date=2017-07-20 |archive-url=https://web.archive.org/web/20170720140022/https://www.gnu.org/licenses/license-list.en.html |url-status=live |archive-date=2017-07-20 |quote=This is a lax permissive non-copyleft free software license, compatible with the GNU GPL.&nbsp;... This license is sometimes called the MIT license, but that term is misleading, since MIT has used many licenses for software.}}</ref>
| GPL compatible = Yes<ref name="gnu-license-list-expat"/><ref name="gnu-license-list-x11"/>
| copyleft = No<ref name="gnu-license-list-expat"/><ref name="gnu-license-list-x11"/>
| linking = Yes
}}
The '''MIT License''' is a [[permissive software license]] originating at the [[Massachusetts Institute of Technology]] (MIT)<ref>{{Cite book |last=Rosen |first=Lawrence E. |title=Open Source Licensing: Software Freedom and Intellectual Property Law |publisher=[[Prentice Hall PTR]] |year=2005 |isbn=0-13-148787-6 |location=Upper Saddle River, NJ |oclc=56012651}}</ref> in the late 1980s.<ref name="history">{{cite web |last=Haff |first=Gordon |title=The mysterious history of the MIT License |url=https://opensource.com/article/19/4/history-mit-license |access-date=2019-07-30 |work=opensource.com |quote=The date? The best single answer is probably 1987. But the complete story is more complicated and even a little mysterious. [...] Precursors from 1985. The X Consortium or X11 License variant from 1987. Or the Expat License from 1998 or 1999.}}</ref> As a permissive license, it puts few restrictions on reuse and has high [[license compatibility]].<ref name="opensoucecomp">{{cite web|url=http://opensource.com/business/14/1/what-license-should-i-use-open-source-project |quote=Permissive licensing simplifies things One reason the business world, and more and more developers [...], favor permissive licenses is in the simplicity of reuse. The license usually only pertains to the source code that is licensed and makes no attempt to infer any conditions upon any other component, and because of this there is no need to define what constitutes a derived work. I have also never seen a license compatibility chart for permissive licenses; it seems that they are all compatible.|title=Should I use a permissive license? Copyleft? Or something in the middle? |date=2014-01-28 |access-date=2015-05-30 |first=Marcus D. |last=Hanwell |publisher=opensource.com}}</ref><ref name="comaptible">{{cite web |url=https://joinup.ec.europa.eu/software/page/licence_compatibility_and_interoperability |work=Open-Source Software  |title=Licence Compatibility and Interoperability |publisher=Joinup |quote=The licences for distributing free or open source software (FOSS) are divided in two families: permissive and copyleft. Permissive licences (BSD, MIT, X11, Apache, Zope) are generally compatible and interoperable with most other licences, tolerating to merge, combine or improve the covered code and to re-distribute it under many licences (including non-free or "proprietary"). |access-date=2015-05-30 |url-status=dead |archive-url=https://web.archive.org/web/20150617130550/https://joinup.ec.europa.eu/software/page/licence_compatibility_and_interoperability |archive-date=2015-06-17 }}</ref>

Unlike [[copyleft]] software licenses, the MIT License allows reuse within [[proprietary software]], provided that all copies of the software or its substantial portions include a copy of the terms of the MIT License and also a copyright notice.<ref name="comaptible"/><ref>{{cite web |url=https://softwareengineering.stackexchange.com/questions/264700/paid-software-includes-mit-licensed-library-does-that-put-my-app-under-mit-too |title=Paid software includes MIT licensed library, does that put my app under MIT too? |website=Software Engineering Stack Exchange |access-date=21 July 2021 }}</ref> In 2015<ref name="github2015" /> and 2025,<ref>{{Cite web |title=GitHub Innovation Graph |url=https://innovationgraph.github.com/global-metrics/licenses |access-date=2025-01-08 |website=innovationgraph.github.com |language=en}}</ref> the MIT License was the most popular software license on [[GitHub]].

Notable projects that use the MIT License include the [[X Window System]], [[Ruby on Rails]], [[Node.js]], [[Lua (programming language)|Lua]], [[jQuery]], [[.NET]], [[Angular (web framework)|Angular]], and [[React (JavaScript library)|React]].<!-- see linked topics for license details -->

== License terms ==
The MIT License has the identifier <code>MIT</code> in the [[SPDX]] License List.<ref name="SPDX-MIT">{{cite web|url=https://spdx.org/licenses/MIT.html|title=MIT License|publisher=SPDX |url-status=live |archive-url=https://web.archive.org/web/20240508230029/https://spdx.org/licenses/MIT.html |archive-date= May 8, 2024 }}</ref><ref name="OSI-MIT" /> It is also known as the "Expat License" {{See below|{{Section link|#Ambiguity and variants}}}}.<ref name="gnu-license-list-expat" /> It has the following terms:<ref>{{Cite web|title=MIT License Explained in Plain English - TLDRLegal|url=https://tldrlegal.com/license/mit-license|access-date=2021-07-07|website=tldrlegal.com}}</ref>

<pre>Copyright (c) <year> <copyright holders>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
</pre>

== History ==

Computer scientist [[Jerry Saltzer]] has published his recollections of its early development, along with documentary evidence.<ref name="saltzer-2020">
{{cite journal
 | last1 = Saltzer | first1 = Jerome H
 | title = The origin of the "MIT license"
 | date = 18 November 2020    <!-- the date shown is the publication date as recorded on the IEEE landing page -->
 | journal = IEEE Annals of the History of Computing
 | volume = 42
 | issue = 4
 | pages = 94–98
 | doi = 10.1109/MAHC.2020.3020234
 | issn = 1934-1547
 | doi-access = free
 }} {{open access}}
</ref>{{R|history}} According to Saltzer, the idea for the license came when working on a [[TCP/IP]] implementation in the Computer Systems Research (CSR) Group of the [[MIT Computer Science and Artificial Intelligence Laboratory|MIT Laboratory for Computer Science (MIT-LCS)]].<ref name="saltzer-2020"/> The group believed that licensing revenue for their software would be small, and wanted to avoid what could sometimes be a large amount of time working with MIT's attorneys negotiating licensing agreements, so they decided to give the software away for free with a copyright notice.<ref name="saltzer-2020"/> Saltzer and Larry Allen worked with attorneys to draft and refine the proposal wording, versions of which were circulated to attorneys by email on January 10, 1984 and used in software publication on February 1, 1984.<ref name="saltzer-2020"/> A new version of the license was put together later in 1985 for the development and release of the [[X Window System]] and [[Project Athena]], and was released in February 1986.<ref name="saltzer-2020"/>

== Variations ==

=== X11 License ===
The '''X11 License''', also known as the '''MIT/X Consortium License''', is a variation on the MIT license, most known for its usage by the [[X Consortium]].<ref>{{citation |url=http://www.xfree86.org/4.0/LICENSE3.html#6 |section=3.3. X Consortium |title=3. X/MIT Licenses |publisher=The XFree86 Project |date=March 2004}}</ref> It has the identifier <code>X11</code> in the [[SPDX]] License List.<ref name="SPDX-X11">{{cite web|url=https://spdx.org/licenses/X11.html|title=X11 License|publisher=SPDX Working Group|website=spdx.org}}</ref><ref name="gnu-license-list-x11" />

It differs from the MIT License mainly by an additional clause restricting use of the copyright holders' name for advertisement.

It has the following terms:<ref>{{Cite web |title=X11 License Explained in Plain English - TLDRLegal |url=https://tldrlegal.com/license/x11-license |access-date=2021-03-26 |website=tldrlegal.com |archive-date=March 3, 2021 |archive-url=https://web.archive.org/web/20210303122101/https://tldrlegal.com/license/x11-license |url-status=dead }}</ref>

<pre>Copyright (C) <date> <copyright holders>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of <copyright holders> shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from <copyright holders>.</pre>

=== MIT No Attribution License ===
{{Infobox software licence
| name = MIT No Attribution License
| image = 
| caption = 
| author = Roman Mamedov, [[Amazon Web Services]]
| version = 
| publisher = 
| date = 28 March 2018
| spdx = MIT-0
| OSI approved = Yes<ref name="osi_approval_mit-0">{{cite web |url=https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2020-August/004915.html |title=[License-review] Request for Legacy Approval of MIT No Attribution License |date=5 August 2020 |first=Pamela |last=Chestek}}</ref>
| Debian approved = n/a
| FSF approved = Yes<ref>https://www.gnu.org/licenses/license-list.html#Expat0</ref>
| GPL compatible = Yes
| copyleft = No
| linking = Yes
| website = https://github.com/aws/mit-0
| deprecated = 
}}
The MIT No Attribution License, a variation of the MIT License, has the identifier <code>MIT-0</code> in the [[SPDX]] License List.<ref name="SPDX-MIT0">{{cite web|url=https://spdx.org/licenses/MIT-0.html|title=MIT No Attribution|publisher=SPDX Working Group|website=spdx.org}}</ref> A request for legacy approval to the [[Open Source Initiative]] was filed on May 15, 2020,<ref>{{cite web|url=https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2020-May/004856.html | title=[License-review] Request for Legacy Approval of MIT No Attribution License |date=15 May 2020| first=Tobie |last=Langel }}</ref> which led to a formal approval on August 5, 2020.<ref name="osi_approval_mit-0"/> By doing so, it forms a [[public-domain-equivalent license]], the same way as [[BSD licenses#0-clause|BSD Zero Clause]].{{citation needed|date=September 2021}} It has the following terms:
<pre>
MIT No Attribution

Copyright <YEAR> <COPYRIGHT HOLDER>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
</pre>

=== Other variations ===
The [[SPDX]] License List contains extra MIT license variations.<ref name="SPDX License List">{{cite web|title=SPDX License List|url=https://spdx.org/licenses/|publisher=SPDX Working Group|website=spdx.org}}</ref> Examples include {{code|MIT-advertising}}, a variation with an additional advertising clause,<ref>{{Cite web |title=Licensing/MIT With Advertising - Fedora Project Wiki |url=https://fedoraproject.org/wiki/Licensing/MIT_With_Advertising |access-date=2025-08-17 |website=fedoraproject.org}}</ref> and {{code|MITNFA}}, a variation which covers the removal or replacement of attributions in cases the software is significantly modified for bug reporting purposes.<ref>{{Cite web |title=Licensing/MITNFA - Fedora Project Wiki |url=https://fedoraproject.org/wiki/Licensing/MITNFA |access-date=2025-08-17 |website=fedoraproject.org}}</ref><ref name="SPDX License List"/>

== Ambiguity and variants ==
The name "MIT License" is potentially ambiguous. The Massachusetts Institute of Technology has used many licenses for software since its creation; for example, MIT offers four licensing options for the [[Fastest Fourier Transform in the West|FFTW]]<ref name="MIT-FFTW-licensing">{{cite web|url=https://tlo.mit.edu/technologies/fftw-fastest-fourier-transform-west|title=FFTW - Fastest Fourier Transform in the West|access-date=17 July 2020|publisher=Massachusetts Institute of Technology}}</ref> C source code library, one of which is the [[GNU General Public License|GPL v2.0]] and the other three of which are not [[Open-source software|open-source]]. The term "MIT License" has also been used to refer to the '''Expat License''' (used for the XML parsing library [[Expat (software)|Expat]]) and to the '''X11 License''' (also called "'''MIT/X Consortium License'''"; used for [[X Window System]] by the [[MIT X Consortium]]).<ref name="gnu-license-list-expat" /> Furthermore, the "MIT License" as published by the [[Open Source Initiative]] is the same as the Expat License.<ref name="OSI-MIT">{{cite web|url=http://opensource.org/licenses/MIT|title= The MIT License |publisher=Open Source Initiative|access-date=5 December 2010}}</ref> Due to this differing use of terms, some prefer to avoid the name "MIT License".<ref name="history"/> The [[Free Software Foundation]] argues that the term is misleading and ambiguous, and recommends against its use.<ref name="gnu-license-list-expat" />

The X Consortium was dissolved late in 1996, and its assets transferred to [[The Open Group]],<ref>{{cite web |url=https://invisible-island.net/personal/copyrights.html#bad_dating |title=Copyrights/comments |last=Dickey |first=Thomas E. |access-date=October 6, 2020}}</ref> which released X11R6 initially under the same license. The X11 License<ref name="gnu-license-list-x11" /> and the X11R6 "MIT License" chosen for [[ncurses]] by the Free Software Foundation<ref>{{cite web |url=http://invisible-island.net/ncurses/ncurses.faq.html#is_it_gpl |title=NCURSES&nbsp;— Frequently Asked Questions (FAQ) |last=Dickey |first=Thomas E. }}</ref> both include the following clause, absent in the Expat License:<ref name="gnu-license-list-expat" />

{{Blockquote|Except as contained in this notice, the name(s) of the above copyright holders shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization.}}

As of 2020, the successor to the X Window System is the [[X.Org Server]], which is licensed under what is effectively the common MIT license, according to the X.org licensing page:<ref name="xorg-license">{{cite web |url=https://www.x.org/archive/current/doc/xorg-docs/License.html |title=Licenses |website=X.Org Foundation}}</ref>
<blockquote>The X.Org Foundation has chosen the following format of the MIT License as the preferred format for code included in the X Window System distribution.   This is a slight variant of the common MIT license form published by the Open Source Initiative</blockquote>

The "slight variant" is the addition of the phrase "(including the next paragraph)" to the second paragraph of the license text, resulting in: "The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software." This inclusion clarifies that the liability paragraph must also be included for the conditions of the license to be met.<ref name="xorg-license" />

The license-management features at popular source code repository [[GitHub]], as well as its "Choose a License" service, do not differentiate between MIT/Expat license variants. The text of the Expat variant is presented as simply the "MIT License" (represented by the [[metadata]] tag <code>mit</code>).<ref name="github-license-docs">{{cite web| url=https://docs.github.com/en/free-pro-team@latest/github/creating-cloning-and-archiving-repositories/licensing-a-repository |title=Licensing a repository |website=GitHub Docs}}</ref><ref name="choosealicense-mit">{{cite web |url=https://choosealicense.com/licenses/mit/ |title=MIT License |website=ChooseALicense.com |date=September 5, 2022 |publisher=[[GitHub]]}}</ref>

==Comparison to other licenses==
===BSD===

The original [[BSD licenses|BSD license]] also includes a clause requiring all advertising of the software to display a notice crediting its authors. This "advertising clause" (since disavowed by UC Berkeley<ref name="update">{{cite web|url=ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change|title=To All Licensees, Distributors of Any Version of BSD|publisher=University of California, Berkeley|date=1999-07-22|archive-url=https://web.archive.org/web/20201120014440/ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change|archive-date=2020-11-20|url-status=dead|access-date=2006-11-15}}</ref>) is present in the modified MIT License used by [[XFree86]].

The [[University of Illinois/NCSA Open Source License]] combines text from both the MIT and BSD licenses; the license grant and disclaimer are taken from the MIT License.{{cn|date=August 2025}}

The [[ISC license]] contains similarities to both the MIT and simplified BSD licenses, the biggest difference being that language deemed unnecessary by the [[Berne Convention]] is omitted.<ref>{{cite web
  | url   = http://www.openbsd.org/policy.html
  | title = Copyright Policy
  | work = [[OpenBSD]]
  | access-date = 6 June 2016
  | quote = The ISC copyright is functionally equivalent to a two-term BSD copyright with language removed that is made unnecessary by the Berne convention.
  }}</ref><ref name="theo2008">{{cite mailing list
  | url    = https://marc.info/?l=openbsd-misc&m=120618313520730&w=2
  | title  = Re: BSD Documentation License?
  | mailing-list = openbsd-misc
  | last = de Raadt
  | first = Theo
  | author-link = Theo de Raadt
  | date   = 21 March 2008
  }}</ref>

===GNU General Public License===
The GPL is explicit about the [[patent]] rights an owner grants when the code or [[derivative work]] is distributed,<ref>{{Cite web|title=Patents and GPLv3 - FSFE|url=https://fsfe.org/activities/gplv3/patents-and-gplv3.html|access-date=2020-12-01|website=FSFE - Free Software Foundation Europe|language=en}}</ref> while the MIT license does not discuss patents. Moreover, the GPL license impacts derivative works, but the MIT license does not.

== Relation to patents ==
Like the BSD license, the MIT license does not include an express patent license although some commentators<ref>{{cite web | url=https://opensource.com/article/18/3/patent-grant-mit-license| archive-url=https://web.archive.org/web/20210123091649/https://opensource.com/article/18/3/patent-grant-mit-license | archive-date=2021-01-23 | date=2021-01-23 | access-date=2021-01-23 | title=Why so little love for the patent grant in the MIT License?}}</ref><ref>{{cite web | url=http://oss-watch.ac.uk/resources/fossandpatents| archive-url=https://web.archive.org/web/20200503103939/http://oss-watch.ac.uk/resources/fossandpatents | archive-date=2020-05-03 | date=2020-05-03 | access-date=2020-05-03 | title=Free and open source software and your patents}}</ref> state that the grant of rights covers all potential restrictions including patents. Both the BSD and the MIT licenses were drafted before the patentability of software was generally recognized under US law.<ref>Stern and Allen, Open Source Licensing, p. 495 in Understanding the Intellectual Property License 2013 (Practicing Law Institute 2013)</ref> The [[Apache License]] version 2.0<ref name="gnu-license-list-expat"/> is a similarly permissive license that includes an explicit contributor's patent license.
Of specific relevance to US jurisdictions, the MIT license uses the terms "sell" and "use" that are also used in defining the rights of a patent holder in [[Title 35 of the United States Code]] section 154. This has been construed by some commentators<ref>{{cite web | url=https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html| archive-url=https://web.archive.org/web/20200503110018/https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html | archive-date=2020-05-03 | date=2020-05-03 | access-date=2020-05-03 | title=The MIT License, Line by Line}}</ref><ref>
{{citation
 | author=Christian H. Nadan
 | volume=26
 | number=8
 | title=Closing the Loophole: Open Source Licensing & the Implied Patent License
 | year=2009
 | journal=The Computer & Internet Lawyer
 | publisher=Aspen Law & Business
 | url=https://download.pli.edu/WebContent/chbs/185480/185480_Chapter22_Adv_Licensing_Agreements_2017_Vol_02_CC121601854800207140.htm
 | quote=By using patent terms like "deal in", "use", and "sell", the MIT license grant is more likely to be deemed to include express patent rights than the BSD license.
}}
</ref> as an unconventional but implicit license in the US to use any underlying patents.

== Reception and popularity ==
According to a 2020 post by WhiteSource Software,<ref name="whitesource2020">{{cite web | url=https://resources.whitesourcesoftware.com/blog-whitesource/top-open-source-licenses-trends-and-predictions | archive-url=https://web.archive.org/web/20200503111426/https://resources.whitesourcesoftware.com/blog-whitesource/top-open-source-licenses-trends-and-predictions | archive-date=2020-05-03 | date=2020-05-03 | access-date=2020-05-03 | title=Open Source Licenses in 2020: Trends and Predictions}}</ref> the MIT license was used in 27% of four million open source packages. In a 2015 [[GitHub]] blog post, the MIT license was the most popular [[open-source license]], used by 45% of repositories, with the [[GNU GPLv2]] coming second at 13% in their sample of repositories.<ref name="github2015">{{cite web|url=https://github.com/blog/1964-license-usage-on-github-com |quote=1 MIT 44.69%, 2 Other 15.68%|title=Open source license usage on GitHub.com |date=2015-03-09 |first=Ben |last=Balter |access-date=2015-11-21 |website=The GitHub Blog }}</ref>

GitHub’s 2025 ''Innovation Graph'' found that repositories under the MIT License account for about one-third of all projects on the platform that declare a license, giving it the largest share of any license tracked.<ref name="GH2025">{{cite web |url=https://innovationgraph.github.com/global-metrics/licenses |title=Global license trends |website=GitHub Innovation Graph |date=January 8, 2025 |access-date=July 14, 2025}}</ref> The Open Source Initiative reported that its MIT License page drew more than a million unique visitors in 2024—over four times the traffic of the next most-viewed OSI-approved license.<ref name="OSI2024">{{cite web |url=https://opensource.org/blog/top-open-source-licenses-in-2024 |title=Top Open Source licenses in 2024 |website=Open Source Initiative |date=December 23, 2024 |access-date=July 14, 2025}}</ref>

== See also ==
{{Portal|Free and open-source software}}
* [[Comparison of free and open-source software licenses]]
* [[ISC license]]—similar to the MIT license, but with language deemed unnecessary removed
* [[:Category:Software using the MIT license]]

== References ==
{{Reflist}}

== Further reading ==
* {{Cite web |url=https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html |title=The MIT License, Line by Line |last1=Mitchell |first1=Kyle E. |date=2016-09-21 |website=/dev/lawyer |archive-url=https://web.archive.org/web/20160928235700/https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html |archive-date=2016-09-28 |url-status=live |access-date=2016-09-28}}

== External links ==
* [https://fedoraproject.org/wiki/Licensing:MIT?rd=Licensing/MIT MIT License variants]
* [http://www.opensource.org/licenses/MIT The MIT License template] (Open Source Initiative official site)
* [http://www.jclark.com/xml/copying.txt Expat License] {{Webarchive|url=https://web.archive.org/web/20220721145318/http://www.jclark.com/xml/copying.txt |date=July 21, 2022 }}
* [https://xfree86.org/3.3.6/COPYRIGHT2.html#3 X11 License]

{{FOSS}}

{{DEFAULTSORT:Mit License}}
[[Category:Free and open-source software licenses]]
[[Category:Permissive software licenses]]
[[Category:Massachusetts Institute of Technology software|*Mit License]]
[[Category:X Window System]]
[[Category:Massachusetts Institute of Technology]]