MIT License: Difference between revisions

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
← Previous edit
VisualWikitext
imported>Boubloub
Link
imported>CuddleChamp
Undid revision 1317881478 by Ebenezerbyte (talk)
 
Line 15: Line 15:
| linking = Yes
| 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. |url=https://www.worldcat.org/oclc/56012651 |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 very few restrictions on reuse and therefore 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>
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 also permits 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, the MIT License was the most popular software license on [[GitHub]],<ref name="github2015" /> and was still the most popular in 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>
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]].
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 ==
== 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 "[[#Ambiguity and variants|Expat License]]".<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>
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>
<pre>Copyright (c) <year> <copyright holders>
Line 32: Line 32:
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.
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>
</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 ==
== Variations ==
Line 64: Line 81:
| 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>
| 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
| Debian approved = n/a
| FSF approved = n/a
| FSF approved = Yes<ref>https://www.gnu.org/licenses/license-list.html#Expat0</ref>
| GPL compatible = Yes
| GPL compatible = Yes
| copyleft = No
| copyleft = No
Line 83: Line 100:


=== Other variations ===
=== Other variations ===
The [[SPDX]] License List contains extra MIT license variations. Examples include:<ref name="SPDX License List">{{cite web|title=SPDX License List|url=https://spdx.org/licenses/|publisher=SPDX Working Group|website=spdx.org}}</ref>
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"/>
* {{code|MIT-advertising}}, a variation with an additional advertising clause.
There is also the Anti-Capitalist Software License (ACSL),<ref>{{Cite web |title=The Anti-Capitalist Software License |url=https://anticapitalist.software/ |access-date=2024-05-08 |website=anticapitalist.software}}</ref> built off of the MIT license. The ACSL is not OSI-approved, nor does it qualify as a free software license as defined by the FSF, since it limits the permissions granted to individuals and organizations that do not operate under capitalist structures, like non-profits and cooperatives.


== Ambiguity and variants ==
== Ambiguity and variants ==
Line 106: Line 121:
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 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.
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
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
Line 143: Line 158:
</ref> as an unconventional but implicit license in the US to use any underlying patents.
</ref> as an unconventional but implicit license in the US to use any underlying patents.


== Origins ==
== 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>
One of the originators of the MIT license, 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}}


== Reception ==
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>
{{As of |2020}}, according to 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. {{As of|2015}}, according to Black Duck Software<ref name="blackduck2015">{{cite web |url=http://www.blackducksoftware.com/resources/data/top-20-licenses |quote=1. MIT license 24%, 2. GNU General Public License (GPL) 2.0 23% |title=Top 20 licenses |publisher=Black Duck Software |access-date=19 November 2015 |date=19 November 2015 |archive-url=https://web.archive.org/web/20130904051147/http://www.blackducksoftware.com/resources/data/top-20-licenses |archive-date=4 September 2013 |url-status=dead }}</ref>{{Better source needed|reason=Source is very informal and in contradiction with Das 2016; no methodology or explanation is given as to how 'or later' licenses are being considered.|date=November 2016}} and a 2015 blog<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> from [[GitHub]], the MIT license was the most popular [[open-source license]], with the [[GNU GPLv2]] coming second in their sample of repositories.


== See also ==
== See also ==

Latest revision as of 16:08, 20 October 2025

Template:Short description Template:Use American English Template:Use mdy dates Template:Infobox software license The MIT License is a permissive software license originating at the Massachusetts Institute of Technology (MIT)[1] in the late 1980s.[2] As a permissive license, it puts few restrictions on reuse and has high license compatibility.[3][4]

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.[4][5] In 2015[6] and 2025,[7] 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, jQuery, .NET, Angular, and React.

License terms

The MIT License has the identifier MIT in the SPDX License List.[8][9] It is also known as the "Expat License" Template:See below.[10] It has the following terms:[11] 

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.

History

Computer scientist Jerry Saltzer has published his recollections of its early development, along with documentary evidence.[12]Template:R 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 Laboratory for Computer Science (MIT-LCS).[12] 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.[12] 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.[12] 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.[12]

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.[13] It has the identifier X11 in the SPDX License List.[14][15]

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:[16] 

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>.

MIT No Attribution License

Template:Infobox software licence The MIT No Attribution License, a variation of the MIT License, has the identifier MIT-0 in the SPDX License List.[17] A request for legacy approval to the Open Source Initiative was filed on May 15, 2020,[18] which led to a formal approval on August 5, 2020.[19] By doing so, it forms a public-domain-equivalent license, the same way as BSD Zero Clause.Script error: No such module "Unsubst". It has the following terms: 

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.

Other variations

The SPDX License List contains extra MIT license variations.[20] Examples include MIT-advertising, a variation with an additional advertising clause,[21] and MITNFA, a variation which covers the removal or replacement of attributions in cases the software is significantly modified for bug reporting purposes.[22][20]

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 FFTW[23] C source code library, one of which is the GPL v2.0 and the other three of which are not open-source. The term "MIT License" has also been used to refer to the Expat License (used for the XML parsing library Expat) and to the X11 License (also called "MIT/X Consortium License"; used for X Window System by the MIT X Consortium).[10] Furthermore, the "MIT License" as published by the Open Source Initiative is the same as the Expat License.[9] Due to this differing use of terms, some prefer to avoid the name "MIT License".[2] The Free Software Foundation argues that the term is misleading and ambiguous, and recommends against its use.[10]

The X Consortium was dissolved late in 1996, and its assets transferred to The Open Group,[24] which released X11R6 initially under the same license. The X11 License[15] and the X11R6 "MIT License" chosen for ncurses by the Free Software Foundation[25] both include the following clause, absent in the Expat License:[10]

<templatestyles src="Template:Blockquote/styles.css" />

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.

Script error: No such module "Check for unknown parameters".

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:[26]

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

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.[26]

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 mit).[27][28]

Comparison to other licenses

BSD

The original 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[29]) 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.Script error: No such module "Unsubst".

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.[30][31]

GNU General Public License

The GPL is explicit about the patent rights an owner grants when the code or derivative work is distributed,[32] 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[33][34] 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.[35] The Apache License version 2.0[10] 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[36][37] 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,[38] 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.[6]

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.[39] 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.[40]

See also

Script error: No such module "Portal".

References

Template:Reflist

Further reading

  • Script error: No such module "citation/CS1".

External links

Template:FOSS

  1. ↑ Script error: No such module "citation/CS1".
  2. ↑ a b Script error: No such module "citation/CS1".
  3. ↑ Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ Script error: No such module "citation/CS1".
  6. ↑ a b Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ Script error: No such module "citation/CS1".
  9. ↑ a b Script error: No such module "citation/CS1".
  10. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named gnu-license-list-expat
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ a b c d e Script error: No such module "Citation/CS1". Template:Open access
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named gnu-license-list-x11
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ Script error: No such module "citation/CS1".
  19. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named osi_approval_mit-0
  20. ↑ a b Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".
  22. ↑ Script error: No such module "citation/CS1".
  23. ↑ Script error: No such module "citation/CS1".
  24. ↑ Script error: No such module "citation/CS1".
  25. ↑ Script error: No such module "citation/CS1".
  26. ↑ a b Script error: No such module "citation/CS1".
  27. ↑ Script error: No such module "citation/CS1".
  28. ↑ Script error: No such module "citation/CS1".
  29. ↑ Script error: No such module "citation/CS1".
  30. ↑ Script error: No such module "citation/CS1".
  31. ↑ Template:Cite mailing list
  32. ↑ Script error: No such module "citation/CS1".
  33. ↑ Script error: No such module "citation/CS1".
  34. ↑ Script error: No such module "citation/CS1".
  35. ↑ Stern and Allen, Open Source Licensing, p. 495 in Understanding the Intellectual Property License 2013 (Practicing Law Institute 2013)
  36. ↑ Script error: No such module "citation/CS1".
  37. ↑ Script error: No such module "citation/CS1".
  38. ↑ Script error: No such module "citation/CS1".
  39. ↑ Script error: No such module "citation/CS1".
  40. ↑ Script error: No such module "citation/CS1".
Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=MIT_License&oldid=3125497"