Comparison of free and open-source software licenses explained

This comparison only covers software licenses which have a linked Wikipedia article for details and which are approved by at least one of the following expert groups: the Free Software Foundation, the Open Source Initiative, the Debian Project and the Fedora Project. For a list of licenses not specifically intended for software, see List of free-content licences.

FOSS licenses

FOSS stands for "Free and Open Source Software". There is no one universally agreed-upon definition of FOSS software and various groups maintain approved lists of licenses. The Open Source Initiative (OSI) is one such organization keeping a list of open-source licenses.^[1] The Free Software Foundation (FSF) maintains a list of what it considers free.^[2] FSF's free software and OSI's open-source licenses together are called FOSS licenses. There are licenses accepted by the OSI which are not free as per the Free Software Definition. The Open Source Definition allows for further restrictions like price, type of contribution and origin of the contribution, e.g. the case of the NASA Open Source Agreement, which requires the code to be "original" work.^{[3] [4]} The OSI does not endorse FSF license analysis (interpretation) as per their disclaimer.^[5]

The FSF's Free Software Definition focuses on the user's unrestricted rights to use a program, to study and modify it, to copy it, and to redistribute it for any purpose, which are considered by the FSF the four essential freedoms.^{[6] [7]} The OSI's open-source criteria focuses on the availability of the source code and the advantages of an unrestricted and community driven development model.^[8] Yet, many FOSS licenses, like the Apache License, and all Free Software licenses allow commercial use of FOSS components.^[9]

General comparison

For a simpler comparison across the most common licenses see free-software license comparison.

The following table compares various features of each license and is a general guide to the terms and conditions of each license, based on seven subjects or categories. Recent tools like the European Commissions' Joinup Licensing Assistant,^[10] makes possible the licenses selection and comparison based on more than 40 subjects or categories, with access to their SPDX identifier and full text. The table below lists the permissions and limitations regarding the following subjects:

• Linking - linking of the licensed code with code licensed under a different license (e.g. when the code is provided as a library)
• Distribution - distribution of the code to third parties
• Modification - modification of the code by a licensee
• Patent grant - protection of licensees from patent claims made by code contributors regarding their contribution, and protection of contributors from patent claims made by licensees
• Private use - whether modification to the code must be shared with the community or may be used privately (e.g. internal use by a corporation)
• Sublicensing - whether modified code may be licensed under a different license (for example a copyright) or must retain the same license under which it was provided
• TM grant - use of trademarks associated with the licensed code or its contributors by a licensee

In this table, "permissive" means the software has minimal restrictions on how it can be used, modified, and redistributed, usually including a warranty disclaimer. "Copyleft" means the software requires that its source code be made publicly available and that all provisions in the license be preserved in derivative works.

License	Author	Latest version	Publication date	Linking	Distribution	Modification	Patent grant	Private use	Sublicensing	TM grant
Academic Free License^[11]		3.0	2002
	Affero Inc	2.0	2007	^[12]
		2.0	2004	^[13]
		2.0	2003-08-06August 6, 2003
		2.0	2000
		42	1998
		3.0		^[14]
		1.0	2003-08-17August 17, 2003
		1.0	2009	^[15] ^[16]
		4.0	2002	^[17]
		4.0	2002						^[18]
		2.1	2013-06-21June 21, 2013
		1.0	2004-12December 1, 2004
		1.0	2001-05May 2001
	Cryptix Foundation		1995
		2.0	2017-08-24August 24, 2017	^[19]	^[20]
	Indiana University^[21]	1.0	2007
		1.2	2017-05May 2017		^[22]		^[23]
FreeBSD	The FreeBSD project		1999-04April 1999	^[24]
		3.0	2007	^[25]	^[26]		^[27]
	Free Software Foundation	3.0	2007-06June 2007	^[28] ^[29]			^[30]
	Free Software Foundation	3.0	2007-06June 2007	^[31]			^[32]
	IBM	1.0	1999-08August 1999
			2003-06June 2003
	LaTeX project	1.3c
			1988	^[33]
		2.0	2012-03January 3, 2012	^[34]
		1.1
	Lawrence Rosen	3.0	2005
	OpenSSL Project
PHP License^[35]	PHP Group	3.01	2019
	Python Software Foundation	3.9.1	2020-10-05May 10, 2020
			1996
	unlicense.org	1	2010-12December 2010
		20021231	2002-12-31December 31, 2002
Do What The Fuck You Want To Public License (WTFPL)		2	2004-12December 2004
XCore Open Source License also separate "Hardware License Agreement"			2011-02February 2011
XFree86 1.1 License	The XFree86 Project, Inc
	Jean-Loup Gailly and Mark Adler

Other licenses that don't have information:

license	Author	Latest version	Publication date
Eiffel Forum License	NICE	2	2002
Intel Open Source License	Intel Corporation
RealNetworks Public Source License	RealNetworks
Reciprocal Public License	Scott Shattuck	1.5	2007
Sun Industry Standards Source License	Sun Microsystems
Sun Public License	Sun Microsystems
Sybase Open Watcom Public License	Open Watcom		2003-01-28
Zope Public License	Zope Foundation	2.1
Server Side Public License	MongoDB	1.0	2018-10-16

Approvals

This table lists for each license what organizations from the FOSS community have approved itbe it as a "free software" or as an "open source" license, how those organizations categorize it, and the license compatibility between them for a combined or mixed derivative work. Organizations usually approve specific versions of software licenses. For instance, a FSF approval means that the Free Software Foundation (FSF) considers a license to be free-software license. The FSF recommends at least "Compatible with GPL" and preferably copyleft. The OSI recommends a mix of permissive and copyleft licenses, the Apache License 2.0, 2- & 3-clause BSD license, GPL, LGPL, MIT license, MPL 2.0, CDDL and EPL.

License and version	FSF approval ^[36]	GPL (v3) compatibility ^[37] ^[38] ^[39] ^[40] ^[41]	OSI approval ^[42]	Debian approval ^[43] ^[44]	Fedora approval ^[45]
Apache License 1.x
Apache License 2.0		^[46]
Apple Public Source License 1.x	^[47]
Apple Public Source License 2.0
Artistic License 1.0	^[48]
Artistic License 2.0
	^[49]				^[50]
			^[51]
			^[52]
		^[53] ^[54] ^[55] ^[56] ^[57] ^[58]
	^[59]		^[60]		^[61]
		^[62]
		^[63]
Eiffel Forum License 2
		^[64]
GNU General Public License v2		^[65]
GNU General Public License v3		^[66] ^[67]
		^[68]	^[69]	^[70]
	^[71]
Mozilla Public License 1.1
Mozilla Public License 2.0		^[72] ^[73]
Python Software Foundation License 2.0.1; 2.1.1 and newer
Reciprocal Public License 1.5
	^[74]		^[75]
Do What The Fuck You Want To Public License (WTFPL)	^[76]		^[77]
		^[78]
Zope Public License 1.0
Zope Public License 2.0

See also

• Free software
• Free-software license
• List of free and open-source software packages
• List of open-source hardware projects
• List of open-source video games
• Open-source license
• Open-source software
• Source-available software
• SPDX-License-identifier
• License proliferation

Notes and References

1. http://opensource.org/licenses/alphabetical Open source licenses - Licenses by Name
2. Web site: Various Licenses and Comments about Them. August 8, 2011. Free Software Foundation.
3. Web site: Various Licenses and Comments about Them: NASA Open Source Agreement. Free Software Foundation.
4. Web site: Licenses by Name. Open Source Initiative. 16 September 2022 .
5. Web site: Other Resources & Disclaimer. Open Source Initiative. While the OSI acknowledges these as potentially helpful resources for the community, it does not endorse any content, contributors or license interpretations from these websites.[...]The OSI does not promote or exclusively favor any of the above resources, but instead mentions them as a neutral, separate third-party..
6. https://www.gnu.org/philosophy/free-software-for-freedom.html "Relationship between the Free Software movement and Open Source movement"
7. https://www.gnu.org/philosophy/free-sw.html "What is Free Software"
8. https://opensource.org/about opensource.org/about
9. Book: Popp, Dr. Karl Michael . Best Practices for commercial use of open source software . 2015 . Books on Demand . Norderstedt, Germany . 978-3738619096.
10. Web site: Joinup Licensing Assistant. 31 March 2020.
11. Web site: OSL 3.0 Explained.
12. Web site: affero.org: Affero General Public License version 2 (AGPLv2).
13. Web site: the section 4 of the apache license version 2.
14. Web site: BSD license. 22 May 2011 .
15. Web site: Using CC0 for public domain software . April 15, 2011 . . May 10, 2011 . May 14, 2011 . https://web.archive.org/web/20110514163106/https://creativecommons.org/weblog/entry/27081 . dead .
16. Web site: Various Licenses and Comments about Them . . April 4, 2015.
17. https://www.fsf.org/blogs/licensing/cc-by-4-0-and-cc-by-sa-4-0-added-to-our-list-of-free-licenses cc-by-4-0-and-cc-by-sa-4-0-added-to-our-list-of-free-licenses
18. Web site: Compatible Licenses . Creative Commons.
19. Web site: Eclipse Public License - v 2.0.
20. Web site: How to Use Popular Open Source Licenses, Explained.
21. Web site: Open Source Collaboration in Higher Education: Guidelines and Report of the Licensing and Policy Framework Summit for Software Sharing in Higher Education. Daniel. Greenstein. Brad. Wheeler. 1 March 2007. scholarworks.iu.edu.
22. Web site: EUPL compatible open source licences.
23. Web site: EUPL text (1.1 & 1.2).
24. Web site: FreeBSD license.
25. https://www.gnu.org/licenses/agpl.html

    section 13 of the GNU AGPLv3 license

26. https://www.gnu.org/copyleft/gpl-howto.html

    GNU licenses copyleft

27. Web site: the GNU Affero General Public License version 3.
28. https://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL

    If library is under GPLv3

29. https://www.gnu.org/licenses/gpl-faq.html#LinkingWithGPL

    Linking with the GNU GPLv3

30. Web site: the GNU General Public License version 3.
31. https://www.gnu.org/licenses/lgpl.html

    the section 4 of the GNU Lesser General Public License version 3

32. Web site: the GNU Lesser General Public License version 3.
33. Web site: MIT License. 31 October 2006 .
34. Web site: MPL version 2.
35. Web site: PHP License 3.01.
36. Web site: Various Licenses and Comments about Them . Free Software Foundation. Licenses. Free Software Foundation.
37. Web site: To be GPL-Compatible has to be compatible with Licenses GNU GPLv3 and GNU GPLv2 – Free Software Foundation . Free Software Foundation. Software Licenses. Free Software Foundation.
38. Web site: GPL-Compatible Free Software Licenses – Free Software Foundation. Free Software Foundation. Software Licenses. Free Software Foundation.
39. Web site: GPL-Incompatible Free Software Licenses – Free Software Foundation. Free Software Foundation. Software Licenses. Free Software Foundation.
40. Web site: GPL-compatible Definition by FSF – Free Software Foundation. Free Software Foundation. GPL-compatible Definition. Free Software Foundation.
41. Web site: GPL-compatible Definition previous version by FSF – Free Software Foundation. Free Software Foundation. GPL-compatible Definition. Free Software Foundation.
42. Web site: The Approved Licenses. Open Source Initiative. License Information. 16 September 2022 . Open Source Initiative.
43. Web site: Debian – License information. Debian. Licenses. Debian.
44. Web site: The DFSG and Software Licenses. Debian wiki.
45. Web site: Licensing – FedoraProject. Fedora. Licenses. Fedora Project.
46. Web site: Apache License, Version 2.0. Free Software Foundation. Licenses. Free Software Foundation.
47. Web site: Apple Public Source License (APSL), version 1.x . 2013-08-07.
48. The original version of the Artistic License is defined as non-free because it is overly vague, not because of the substance of the license. The FSF encourages projects to use the Clarified Artistic License instead.
49. Web site: Various Licenses and Comments about Them. 2016-01-05. Free Software Foundation. 2016-01-05.
50. Web site: Licensing/Beerware. Fedora Project. 2015-03-10.
51. Web site: The BSD License:Licensing . Open Source Initiative . 1 February 2021 . https://web.archive.org/web/20091129081849/http://www.opensource.org/licenses/bsd-license.php . 29 November 2009 . dead.
52. Web site: [License-review] Please rename "Free Public License-1.0.0" to 0BSD. ]. . 2019-02-11.
53. Web site: Various Licenses and Comments About Them - Common Development and Distribution License . Free Software Foundation . 2006-12-31.
54. Web site: Michael Larabel. Michael Larabel . Ubuntu Is Planning To Make The ZFS File-System A "Standard" Offering . Phoronix. 6 October 2015.
55. Web site: Canonical. Ubuntu Insights . ZFS Licensing and Linux . Dustin Kirkland . 18 February 2016.
56. http://blog.hansenpartnership.com/are-gplv2-and-cddl-incompatible/ Are GPLv2 and CDDL incompatible?
57. Web site: The Linux Kernel, CDDL and Related Issues. 26 February 2016. Eben . Moglen . Mishi . Choudhary.
58. https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ GPL Violations Related to Combining ZFS and Linux
59. Web site: Various Licenses and Comments about Them - GNU Project - Free Software Foundation.
60. Web site: Frequently Answered Questions . opensource.org . 21 October 2007 . "CC0 was not explicitly rejected, but the License Review Committee was unable to reach consensus that it should be approved".
61. Web site: Licensing:Main.
62. Web site: Creative Commons BY-SA 4.0 declared one-way compatible with GNU GPL version 3 — Free Software Foundation — working together for free software.
63. Web site: Educational Community License 2.0. Free Software Foundation. Licenses. Free Software Foundation.
64. https://www.gnu.org/licenses/

    "We use only licenses that are compatible with the GNU GPL for GNU software."

65. But can be made compatible by upgrading to GPLv3 via the optional "or later" clause added in most GPLv2 license texts.
66. But not with GPLv2 without "or later" clause.
67. Web site: Frequently Asked Questions about the GNU Licenses – Is GPLv3 compatible with GPLv2?. gnu.org. 3 June 2014 . No. Some of the requirements in GPLv3, such as the requirement to provide Installation Information, do not exist in GPLv2. As a result, the licenses are not compatible: if you tried to combine code released under both these licenses, you would violate section 6 of GPLv2. However, if code is released under GPL "version 2 or later," that is compatible with GPLv3 because GPLv3 is one of the options it permits..
68. Web site: Re: Proposed statement WRT GNU FDL.
69. Web site: SPDX License List | Software Package Data Exchange (SPDX).
70. Web site: General Resolution: Why the GNU Free Documentation License is not suitable for Debian main.
71. Web site: A Quick Guide to GPLv3. Free Software Foundation. Licenses. Free Software Foundation.
72. MPL 2.0 is GPL compatible unless marked "Incompatible with Secondary Licenses".
73. Web site: MPL 2.0 FAQ. Mozilla Foundation. Licenses. Mozilla Foundation.
74. Web site: Various Licenses and Comments about Them - GNU Project - Free Software Foundation.
75. Web site: [License-review] Request for legacy approval: The Unlicense].
76. Listed as WTFPL.
77. Web site: OSI Board Meeting Minutes, Wednesday, March 4, 2009. 4 May 2009 .
78. Web site: XFree86 1.1 License. Free Software Foundation. Licenses. Free Software Foundation.