Last updated
Unlicense logo
AuthorArto Bendiken
SPDX identifierUnlicense
FSF approved Yes [1]
OSI approved Yes [2]
GPL compatible Yes [1]
Copyleft No [1]
Linking from code with a different licence Yes
Website unlicense.org

The Unlicense is a public domain equivalent license with a focus on an anti-copyright message. It was first published on January 1 (Public Domain Day), 2010. The Unlicense offers a public domain waiver text with a fall-back public-domain-like license, inspired by permissive licenses but without an attribution clause. [3] [4] In 2015, GitHub reported that approximately 102,000 of their 5.1 million licensed projects (2% of licensed projects on GitHub.com) use the Unlicense. [5]



In a post published on January 1 (Public Domain Day), 2010, Arto Bendiken outlined his reasons for preferring public domain software, namely: the nuisance of dealing with licensing terms (for instance license incompatibility), the threat inherent in copyright law, and the impracticability of copyright law. [6]

On January 23, 2010, Bendiken followed-up on his initial post. In this post, he explained that the Unlicense is based on the copyright waiver of SQLite with the no-warranty statement from the MIT License. He then walked through the license, commenting on each part. [7]

In a post published in December 2010, Bendiken further clarified what it means to "license" and "unlicense" software. [8]

On January 1, 2011, Bendiken reviewed the progress and adoption of the Unlicense. He admits that it is "difficult to give estimates of current Unlicense adoption" but suggests there are "many hundreds of projects using the Unlicense". [9]

In January 2012, when discussed on OSI's license-review mailing list, the Unlicense was brushed off as a crayon license. [10] A request for legacy approval was filed in March 2020, [11] which led to a formal approval in June 2020. [2]

License terms

The license terms of the Unlicense is as follows: [4]

This is free and unencumbered software released into the public domain.  Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.  In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.  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 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.  For more information, please refer to <http://unlicense.org/> 


The Free Software Foundation states that "Both public domain works and the lax license provided by the Unlicense are compatible with the GNU GPL." However, for dedicating software to the public domain it recommends CC0 over the Unlicense, stating that CC0 "is more thorough and mature than the Unlicense". [1]

The Fedora Project recommends CC0 over the Unlicense because the former is "a more comprehensive legal text". [12]

Google does not allow contributions to projects under public domain equivalent licenses like the Unlicense (and CC0), while allowing contributions to 0BSD licensed and US government PD projects. [13]

In December 2010, Mike Linksvayer, the vice president of Creative Commons at the time, wrote in an identi.ca conversation "I like the movement" in speaking of the Unlicense effort. [14] [15]

The Unlicense has been criticized, for instance by the OSI, for being possibly inconsistent and non-standard, and for making it difficult for some projects to accept Unlicensed code as third-party contributions; leaving too much room for interpretation; and possibly being incoherent in some legal systems. [16] [17] [10]

Notable projects that use the Unlicense include youtube-dl, [18] Second Reality, [19] and the Gloom source code. [20]

See also

Related Research Articles

Free software Software licensed to preserve user freedoms

Free software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give end-users ultimate control over the software and, subsequently, over their devices.

MIT License Permissive free software license

The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license compatibility. The Wikipedia and Wikimedia Commons projects use the alternative name Expat License.

Apache License Free software license developed by the ASF

The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties. The ASF and its projects release their software products under the Apache License. The license is also used by many non-ASF projects.

Source-available software is software released through a source code distribution model that includes arrangements where the source can be viewed, and in some cases modified, but without necessarily meeting the criteria to be called open-source. The licenses associated with the offerings range from allowing code to be viewed for reference to allowing code to be modified and redistributed for both commercial and non-commercial purposes.

An anti-copyright notice is a specific statement that is added to a work in order to encourage wide distribution. Such notices are legally required to host such specific media; under the Berne Convention in international copyright law, works are protected even if no copyright statement is attached to them. However, "anti-copyright" statements typically do not take the form of either sophisticated public copyright licenses or a simple dedication to the public domain; instead, they usually just encourage wide distribution. Depending on jurisdiction, it is possible to denounce all claims to copyright in a work including moral rights in a written disclaimer.

A software license is a legal instrument governing the use or redistribution of software. Under United States copyright law, all software is copyright protected, in both source code and object code forms, unless that software was developed by the United States Government, in which case it cannot be copyrighted. Authors of copyrighted software can donate their software to the public domain, in which case it is also not covered by copyright and, as a result, cannot be licensed.

A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license with only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. As of 2016, the most popular free-software license is the permissive MIT license.

Alternative terms for free software, such as open source, FOSS, and FLOSS, have been a controversial issue among free and open-source software users from the late 1990s onwards. These terms share almost identical licence criteria and development practices.

Eclipse Public License Free software license similar to the Common Public License

The Eclipse Public License (EPL) is a free and open source software license most notably used for the Eclipse IDE and other projects by the Eclipse Foundation. It replaces the Common Public License (CPL) and removes certain terms relating to litigations related to patents.

This is a comparison of free and open-source software licences. The comparison only covers software licences with a linked article for details, approved by at least one expert group at the FSF, the OSI, the Debian project or the Fedora project. For a list of licences not specifically intended for software, see List of free content licences.

Public-domain software

Public-domain software is software that has been placed in the public domain: in other words, there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, or sold even without any attribution by anyone; this is unlike the common case of software under exclusive copyright, where software licenses grant limited usage rights.

WTFPL License for permissive use of intellectual property rights

WTFPL is a GPL-compatible permissive license most commonly used as a free software license. As a public domain like license, the WTFPL is essentially the same as dedication to the public domain. It allows redistribution and modification of the work under any terms. The title is an abbreviation of "Do What The Fuck You Want To Public License".

Public-domain-equivalent license License that waives all copyright and related rights, to the extent permitted by the law in each jurisdiction

Public-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses.

Mike Linksvayer

Mike Linksvayer is an intellectual freedom and commons proponent, known as a technology entrepreneur, developer and activist from co-founding Bitzi and leadership of Creative Commons. He is GitHub's Policy Director.

Free-software license license allowing software modification and redistribution

A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.

BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.

Open-core model business model monetizing commercial open-source software

The open-core model is a business model for the monetization of commercially produced open-source software. Coined by Andrew Lampitt in 2008, the open-core model primarily involves offering a "core" or feature-limited version of a software product as free and open-source software, while offering "commercial" versions or add-ons as proprietary software.

A public license or public copyright licenses is a license by which a copyright holder as licensor can grant additional copyright permissions to any and all persons in the general public as licensees. By applying a public license to a work, provided that the licensees obey the terms and conditions of the license, copyright holders give permission for others to copy or change their work in ways that would otherwise infringe copyright law.

Software relicensing is applied in open-source software development when software licenses of software modules are incompatible and are required to be compatible for a greater combined work. Licenses applied to software as copyrightable works, in source code as binary form, can contain contradictory clauses. These requirements can make it impossible to combine source code or content of several software works to create a new combined one.


  1. 1 2 3 4 "Various Licenses and Comments about Them - GNU Project § The Unlicense". Free Software Foundation. Retrieved February 10, 2017.
  2. 1 2 Chestek, Pamela (June 16, 2020). "[License-review] Request for legacy approval: The Unlicense". Archived from the original on September 8, 2020. There is general agreement that the document is poorly drafted. It is an attempt to dedicate a work to the public domain (which, taken alone, would not be approved as an open source license) but it also has wording commonly used for license grants.There was some discussion about the legal effectiveness of the document, in particular how it would operate in a jurisdiction where one cannot dedicate a work to the public domain. The lawyers who opined on the issue, both US and non-US, agreed that the document would most likely be interpreted as a license and that the license met the OSD. It is therefore recommended for approval.
  3. Joe Brockmeier (January 11, 2010). "The Unlicense: A License for No License". OStatic. Archived from the original on January 22, 2017.
  4. 1 2 "Unlicense Yourself: Set Your Code Free" . Retrieved February 28, 2017.
  5. Balter, Ben (2015-03-09). "Open source license usage on GitHub.com". github.com . Retrieved 2015-11-21. 1 MIT 44.69%, 2 Other 15.68%, 3 GPLv2 12.96%, 4 Apache 11.19%, 5 GPLv3 8.88%, 6 BSD 3-clause 4.53%, 7 Unlicense 1.87%, 8 BSD 2-clause 1.70%, 9 LGPLv3 1.30%, 10 AGPLv3 1.05% (30 million × 2% × 17% = 102k)
  6. Arto Bendiken (January 1, 2010). "Set Your Code Free" . Retrieved February 10, 2017. anybody affixing a licensing statement to open-source software is guilty of either magical thinking or of having an intention to follow up on the implied threat
  7. Arto Bendiken (January 23, 2010). "Dissecting the Unlicense: Software Freedom in Four Clauses and a Link" . Retrieved February 10, 2017.
  8. Arto Bendiken (December 19, 2010). "Licensed, License-Free, and Unlicensed Code" . Retrieved February 10, 2017.
  9. Arto Bendiken (January 1, 2011). "The Unlicense: The First Year in Review" . Retrieved February 10, 2017.
  10. 1 2 Moen, Rick (January 3, 2012). "[License-review] OSI, legal conditions outside the "four corners" of the license, and PD/CC 0 [was Re: Can OSI specify that public domain is open source?]". Open Source Initiative. Archived from the original on March 1, 2017. Retrieved February 10, 2017.
  11. Jaeckel, Steffen (March 28, 2020). "[License-review] Request for legacy approval: The Unlicense". Archived from the original on September 8, 2020.
  12. "Licensing/Unlicense". Fedora Project. August 14, 2014. Retrieved February 28, 2017. Fedora recommends use of CC-0 over this license, because it is a more comprehensive legal text around this tricky issue. It is also noteworthy that some MIT variant licenses which contain the right to "sublicense" are closer to a true Public Domain declaration than the one in the "Unlicense" text.
  13. "Open Source Patching". Google . Retrieved 2020-09-29.
  14. Mike Linksvayer (December 17, 2010). "Conversation". Identi.ca. Archived from the original on August 16, 2011. Retrieved February 28, 2017. @bendiken surely there's a better name than copyfree, but I like the movement and look fwd to your roundup.
  15. Arto Bendiken (December 18, 2010). "CC0 and the Unlicense". Google Groups. Retrieved February 28, 2017. In case it's of interest, I'm engaged in an ongoing Identi.ca conversation with Mike Linksvayer, the vice president of Creative Commons [] In short, the folks at Creative Commons are aware of the Unlicense initiative, and apparently supportive of it.
  16. Val Markovic (Valloric) (July 6, 2014). "Use a working license instead of UNLICENSE". GitHub . Retrieved February 9, 2017.
  17. cgt (May 3, 2012). "What is wrong with the Unlicense?". Software Engineering Stack Exchange. Retrieved February 10, 2017.
  18. "youtube-dl GitHub page". GitHub. Retrieved 2 October 2016.
  19. Mika Tuomi (August 1, 2013). "SecondReality/UNLICENSE at master · mtuomi/SecondReality". GitHub. Retrieved February 28, 2017.
  20. GloomAmiga on GitHub - Source code of Gloom released in May 2017