Comparison of free and open-source software licenses

Appearance move to sidebar hide

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. The Free Software Foundation (FSF) maintains a list of what it considers free. 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. The OSI does not endorse FSF license analysis (interpretation) as per their disclaimer.

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. 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. Yet, many FOSS licenses, like the Apache License, and all Free Software licenses allow commercial use of FOSS components.

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, 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:

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.

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


This table lists for each license what organizations from the FOSS community have approved it – be 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.

  1. ^ 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.
  2. ^ But can be made compatible by upgrading to GPLv3 via the optional "or later" clause added in most GPLv2 license texts.
  3. ^ But not with GPLv2 without "or later" clause.
  4. ^ MPL 2.0 is GPL compatible unless marked "Incompatible with Secondary Licenses".
  5. ^ Listed as WTFPL.

See also


  1. ^ See footnote of the Beerware article


  1. ^ Open source licenses - Licenses by Name on
  2. ^ "Various Licenses and Comments about Them". Free Software Foundation. Retrieved August 8, 2011.
  3. ^ "Various Licenses and Comments about Them: NASA Open Source Agreement". Free Software Foundation.
  4. ^ "Licenses by Name". Open Source Initiative. 16 September 2022.
  5. ^ "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. ^ "Relationship between the Free Software movement and Open Source movement", Free Software Foundation, Inc
  7. ^ "What is Free Software", Free Software Foundation, Inc
  8. ^ "Open source is a development method for software that harnesses the power of distributed peer review and transparency of process. The promise of open source is better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in."
  9. ^ Popp, Dr. Karl Michael (2015). Best Practices for commercial use of open source software. Norderstedt, Germany: Books on Demand. ISBN 978-3738619096.
  10. ^ "Joinup Licensing Assistant". Retrieved 31 March 2020.
  11. ^ a b "OSL 3.0 Explained".
  12. ^ a b c d " Affero General Public License version 2 (AGPLv2)".
  13. ^ a b c d e f g "the section 4 of the apache license version 2".
  14. ^ a b c d e f g "BSD license". 22 May 2011.
  15. ^ "Using CC0 for public domain software". Creative Commons. April 15, 2011. Archived from the original on May 14, 2011. Retrieved May 10, 2011.
  16. ^ "Various Licenses and Comments about Them". GNU Project. Retrieved April 4, 2015.
  17. ^ a b cc-by-4-0-and-cc-by-sa-4-0-added-to-our-list-of-free-licenses (2015)
  18. ^ "Compatible Licenses". Creative Commons.
  19. ^ a b c d e f g "Eclipse Public License - v 2.0".
  20. ^ "How to Use Popular Open Source Licenses, Explained".
  21. ^ Greenstein, Daniel; Wheeler, Brad (1 March 2007). "Open Source Collaboration in Higher Education: Guidelines and Report of the Licensing and Policy Framework Summit for Software Sharing in Higher Education" – via
  22. ^ a b c d "EUPL compatible open source licences".
  23. ^ a b c "EUPL text (1.1 & 1.2)".
  24. ^ a b c d e f g "FreeBSD license".
  25. ^ a b : section 13 of the GNU AGPLv3 license
  26. ^ a b c d e f g h i : GNU licenses copyleft
  27. ^ a b c "the GNU Affero General Public License version 3".
  28. ^ : If library is under GPLv3
  29. ^ : Linking with the GNU GPLv3
  30. ^ a b c "the GNU General Public License version 3".
  31. ^ : the section 4 of the GNU Lesser General Public License version 3
  32. ^ a b "the GNU Lesser General Public License version 3".
  33. ^ a b c d e f g "MIT License". 31 October 2006.
  34. ^ a b c d e f g "MPL version 2".
  35. ^ "PHP License 3.01".
  36. ^ Free Software Foundation. "Various Licenses and Comments about Them". Licenses. Free Software Foundation.
  37. ^ Free Software Foundation. "To be GPL-Compatible has to be compatible with Licenses GNU GPLv3 and GNU GPLv2 – Free Software Foundation". Software Licenses. Free Software Foundation.
  38. ^ Free Software Foundation. "GPL-Compatible Free Software Licenses – Free Software Foundation". Software Licenses. Free Software Foundation.
  39. ^ Free Software Foundation. "GPL-Incompatible Free Software Licenses – Free Software Foundation". Software Licenses. Free Software Foundation.
  40. ^ Free Software Foundation. "GPL-compatible Definition by FSF – Free Software Foundation". GPL-compatible Definition. Free Software Foundation.
  41. ^ Free Software Foundation. "GPL-compatible Definition previous version by FSF – Free Software Foundation". GPL-compatible Definition. Free Software Foundation.
  42. ^ Open Source Initiative (16 September 2022). "The Approved Licenses". License Information. Open Source Initiative.
  43. ^ Debian. "Debian – License information". Licenses. Debian.
  44. ^ "The DFSG and Software Licenses". Debian wiki.
  45. ^ Fedora. "Licensing – FedoraProject". Licenses. Fedora Project.
  46. ^ Free Software Foundation. "Apache License, Version 2.0". Licenses. Free Software Foundation.
  47. ^ "Apple Public Source License (APSL), version 1.x". Retrieved 2013-08-07.
  48. ^ a b "Various Licenses and Comments about Them". Free Software Foundation. 2016-01-05. Retrieved 2016-01-05.
  49. ^ "Licensing/Beerware". Fedora Project. Retrieved 2015-03-10.
  50. ^ "The BSD License:Licensing". Open Source Initiative. Archived from the original on 29 November 2009. Retrieved 1 February 2021.
  51. ^ " Please rename "Free Public License-1.0.0" to 0BSD". Open Source Initiative. Retrieved 2019-02-11.
  52. ^ "Various Licenses and Comments About Them - Common Development and Distribution License". Free Software Foundation. Retrieved 2006-12-31.
  53. ^ Michael Larabel (6 October 2015). "Ubuntu Is Planning To Make The ZFS File-System A "Standard" Offering". Phoronix.
  54. ^ Dustin Kirkland (18 February 2016). "ZFS Licensing and Linux". Ubuntu Insights. Canonical.
  55. ^ Are GPLv2 and CDDL incompatible? on by James E.J. Bottomley "What the above analysis shows is that even though we presumed combination of GPLv2 and CDDL works to be a technical violation, there's no way actually to prosecute such a violation because we can’t develop a convincing theory of harm resulting. Because this makes it impossible to take the case to court, effectively it must be concluded that the combination of GPLv2 and CDDL, provided you’re following a GPLv2 compliance regime for all the code, is allowable." (23 February 2016)
  56. ^ Moglen, Eben; Choudhary, Mishi (26 February 2016). "The Linux Kernel, CDDL and Related Issues".
  57. ^ GPL Violations Related to Combining ZFS and Linux on by Bradley M. Kuhn and Karen M. Sandler (February 25, 2016)
  58. ^ a b c "Various Licenses and Comments about Them - GNU Project - Free Software Foundation".
  59. ^ "Frequently Answered Questions". 21 October 2007. CC0 was not explicitly rejected, but the License Review Committee was unable to reach consensus that it should be approved
  60. ^ a b "Licensing:Main".
  61. ^ "Creative Commons BY-SA 4.0 declared one-way compatible with GNU GPL version 3 — Free Software Foundation — working together for free software".
  62. ^ Free Software Foundation. "Educational Community License 2.0". Licenses. Free Software Foundation.
  63. ^ : "We use only licenses that are compatible with the GNU GPL for GNU software."
  64. ^ a b "Frequently Asked Questions about the GNU Licenses – Is GPLv3 compatible with GPLv2?". Retrieved 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.
  65. ^ "Re: Proposed statement WRT GNU FDL".
  66. ^ "SPDX License List | Software Package Data Exchange (SPDX)".
  67. ^ "General Resolution: Why the GNU Free Documentation License is not suitable for Debian main".
  68. ^ Free Software Foundation. "A Quick Guide to GPLv3". Licenses. Free Software Foundation.
  69. ^ Mozilla Foundation. "MPL 2.0 FAQ". Licenses. Mozilla Foundation.
  70. ^ "Various Licenses and Comments about Them - GNU Project - Free Software Foundation".
  71. ^ " Request for legacy approval: The Unlicense".
  72. ^ "OSI Board Meeting Minutes, Wednesday, March 4, 2009". 4 May 2009.
  73. ^ Free Software Foundation. "XFree86 1.1 License". Licenses. Free Software Foundation.