Comparison of free and open-source software licences

Last updated

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.

Contents

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 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:

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.

LicenseAuthorLatest versionPublication dateLinkingDistributionModificationPatent grantPrivate useSublicensingTM grant
Academic Free License [11] Lawrence E. Rosen 3.02002 Permissive PermissivePermissiveYesYesPermissiveNo
Affero General Public License Affero Inc2.02007 Copylefted [12] Copyleft except for the GNU AGPL [12] Copyleft [12] ?Yes [12] ??
Apache License Apache Software Foundation 2.02004Permissive [13] Permissive [13] Permissive [13] Yes [13] Yes [13] Permissive [13] No [13]
Apple Public Source License Apple Computer 2.0August 6, 2003Permissive?Limited????
Artistic License Larry Wall 2.02000With restrictionsWith restrictionsWith restrictionsNoPermissiveWith restrictionsNo
Beerware Poul-Henning Kamp 421987PermissivePermissivePermissiveNoPermissivePermissiveNo
BSD License Regents of the University of California 3.0?Permissive [14] Permissive [14] Permissive [14] Manually [14] Yes [14] Permissive [14] Manually [14]
Boost Software License ?1.0August 17, 2003Permissive?Permissive????
Creative Commons Zero Creative Commons 1.02009Public Domain [15] [16] Public DomainPublic DomainNoPublic DomainPublic DomainNo
CC BY Creative Commons 4.02002Permissive [17] PermissivePermissiveNoYesPermissiveNo
CC BY-SA Creative Commons 4.02002Copylefted [17] CopyleftedCopyleftedNoYesCopylefted [18] No
CeCILL CEA / CNRS / INRIA 2.1June 21, 2013PermissivePermissivePermissiveNoPermissiveWith restrictionsNo
Common Development and Distribution License Sun Microsystems 1.0December 1, 2004Permissive?Limited????
Common Public License IBM 1.0May 2001Permissive?Copylefted????
Cryptix General License Cryptix FoundationN/A1995PermissivePermissivePermissiveManuallyYes?Manually
Eclipse Public License Eclipse Foundation 2.0August 24, 2017Permissive [19] Copylefted [19] [20] Copylefted [19] Yes [19] Yes [19] Copylefted [19] No [19]
Educational Community License Indiana University [21] 1.02007Permissive?Permissive????
European Union Public Licence European Commission 1.2May 2017Permissive, according to EU law (Recitals 10 & 15 Directive 2009/24/EC)Copylefted, with an explicit compatibility list [22] Copylefted, with an explicit compatibility list [22] Yes [23] Yes [23] Copylefted, with an explicit compatibility list [22] No [23]
FreeBSD The FreeBSD projectN/AApril 1999Permissive [24] Permissive [24] Permissive [24] Manually [24] Permissive [24] Permissive [24] Manually [24]
GNU Affero General Public License Free Software Foundation 3.02007GNU GPLv3 only [25] Copylefted [26] Copylefted [26] Yes [27] No network usage [27] Copylefted [26] Yes [27]
GNU General Public License Free Software Foundation3.0June 2007GPLv3 compatible only [28] [29] Copylefted [26] Copylefted [26] Yes [30] Yes [30] Copylefted [26] Yes [30]
GNU Lesser General Public License Free Software Foundation3.0June 2007With restrictions [31] Copylefted [26] Copylefted [26] Yes [32] YesCopylefted [26] Yes [32]
IBM Public License IBM1.0August 1999Copylefted?Copylefted????
ISC license Internet Systems Consortium N/AJune 2003PermissivePermissivePermissiveManuallyPermissivePermissiveManually
LaTeX Project Public License LaTeX project1.3c?Permissive?Permissive????
Microsoft Public License Microsoft N/A?CopyleftedCopyleftedCopyleftedNoPermissive?No
MIT license / X11 license MIT N/A1988Permissive [33] Permissive [33] Permissive [33] Manually [33] Yes [33] Permissive [33] Manually [33]
Mozilla Public License Mozilla Foundation 2.0January 3, 2012Permissive [34] Copylefted [34] Copylefted [34] Yes [34] Yes [34] Copylefted [34] No [34]
Netscape Public License Netscape 1.1?Limited?Limited????
Open Software License [11] Lawrence Rosen3.02005PermissiveCopyleftedCopyleftedYesYesCopylefted?
OpenSSL license OpenSSL ProjectN/A?Permissive?Permissive????
PHP License [35] PHP Group3.012019With restrictionsWith restrictionsWith restrictionsYesYesWith restrictionsManually
Python Software Foundation License Python Software Foundation3.9.12020-10-05PermissivePermissivePermissiveYesPermissivePermissiveNo
Q Public License Trolltech ??Limited?Limited????
Sleepycat License Sleepycat Software N/A1996PermissiveWith restrictionsPermissiveNoYesNoNo
Unlicense unlicense.org1December 2010Permissive/Public domainPermissive/Public domainPermissive/Public domain?Permissive/Public domainPermissive/Public domain?
W3C Software Notice and License W3C 20021231December 31, 2002Permissive?Permissive????
Do What The Fuck You Want To Public License (WTFPL)Banlu Kemiyatorn, Sam Hocevar 2December 2004Permissive/Public domainPermissive/Public domainPermissive/Public domainNoYesYesNo
XCore Open Source License
also separate "Hardware License Agreement"
XMOS ?February 2011PermissivePermissivePermissiveManuallyYesPermissive?
XFree86 1.1 License The XFree86 Project, Inc??Permissive?Permissive????
zlib/libpng license Jean-Loup Gailly and Mark Adler??Permissive?Permissive????

Other licenses that don't have information:

licenseAuthorLatest versionPublication date
Eiffel Forum License NICE22002
Intel Open Source License Intel Corporation N/A?
RealNetworks Public Source License RealNetworks ??
Reciprocal Public License Scott Shattuck1.52007
Sun Industry Standards Source License Sun Microsystems??
Sun Public License Sun Microsystems??
Sybase Open Watcom Public License Open Watcom N/A2003-01-28
Zope Public License Zope Foundation 2.1?
Server Side Public License MongoDB 1.02018-10-16

Approvals

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.

License and version FSF approval
[36]
GPL (v3) compatibility
[37] [38] [39] [40] [41]
OSI approval
[42]
Debian approval
[43] [44]
Fedora approval
[45]
Academic Free License YesNoYesNoYes
Affero General Public License 3.0YesYesYesYesYes
Apache License 1.xYesNoYesYesYes
Apache License 2.0YesGPLv3 only [46] YesYesYes
Apple Public Source License 1.xNo [47] NoYesNoNo
Apple Public Source License 2.0YesNoYesNoYes
Artistic License 1.0No [note 1] NoYesYesNo
Artistic License 2.0YesYesYesYesYes
Beerware License see "Informal license" section [48] see "Informal license" section [48] NoNoYes [49]
Original BSD license YesNoNo [50] YesYes
Revised BSD license YesYesYesYesYes
Simplified BSD license YesYesYesYesYes
Zero-Clause BSD License ??Yes [51] ??
Boost Software License YesYesYesYesYes
CeCILL YesYesYesYesYes
Common Development and Distribution License YesGPLv3 (GPLv2 disputed) [52] [53] [54] [55] [56] [57] YesYesYes
Common Public License YesNoYesYesYes
Creative Commons Zero Yes [58] Yes [58] No [59] Partial [60] [61] Yes [62]
Creative Commons BY-SA 4.0 YesGPLv3 [63] ?Yes?
Cryptix General License YesYesYesYesYes
Eclipse Public License YesNoYesYesYes
Educational Community License YesYes [64] YesNoYes
Eiffel Forum License 2YesYesYesYesYes
European Union Public Licence YesYes [22] YesYesYes
GNU Affero General Public License YesYes [25] [65] YesYesYes
GNU General Public License v2YesNo [note 2] [66] YesYesYes
GNU General Public License v3YesYes [note 3] [66] YesYesYes
GNU Lesser General Public License YesYesYesYesYes
GNU Free Documentation License YesNo [67] Yes [68] No [69] No
IBM Public License YesNoYesYesYes
Intel Open Source License YesYesYesNoNo
ISC license Yes [70] YesYesYesYes
LaTeX Project Public License YesNoYesYesYes
Microsoft Public License YesNoYesNoYes
Microsoft Reciprocal License YesNoYesNoYes
MIT license / X11 license YesYesYesYesYes
Mozilla Public License 1.1YesNoYesYesYes
Mozilla Public License 2.0YesYes [note 4] [71] YesYesYes
NASA Open Source Agreement NoNoYes?No
Netscape Public License YesNoNoNoYes
Open Software License YesNoYesNoYes
OpenSSL license YesNoNoYesYes
PHP License YesNoYesYesYes
Python Software Foundation License 2.0.1; 2.1.1 and newerYesYesYesYesYes
Q Public License YesNoYesNoYes
Reciprocal Public License 1.5NoNoYesNoNo
Sleepycat License YesYesYesYesYes
Sun Industry Standards Source License YesNoYesNoYes
Sun Public License YesNoYesNoYes
Sybase Open Watcom Public License NoNoYesNoNo
Unlicense Yes [72] Yes [58] Yes [73] ?Yes [62]
W3C Software Notice and License YesYesYesYesYes
Do What The Fuck You Want To Public License (WTFPL)Yes [note 5] YesNo [74] YesYes
XFree86 1.1 License YesYes [75] NoNoNo
zlib/libpng license YesYesYesYesYes
Zope Public License 1.0YesNoNoNoYes
Zope Public License 2.0YesYesYesNoYes
  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

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.

The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run the software, to study the software, to modify the software, and to share copies of the software. Software which meets these requirements, The Four Essential Freedoms of Free Software, is termed free software.

GNU Lesser General Public License Free-software license

The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any developer who modifies an LGPL-covered component is required to make their modified version available under the same LGPL license. For proprietary software, code under the LGPL is usually used in the form of a shared library, so that there is a clear separation between the proprietary and LGPL components. The LGPL is primarily used for software libraries, although it is also used by some stand-alone applications.

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.

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.

The Open Software License (OSL) is a software license created by Lawrence Rosen. The Open Source Initiative (OSI) has certified it as an open-source license, but the Debian project judged version 1.1 to be incompatible with the DFSG. The OSL is a copyleft license, with a termination clause triggered by filing a lawsuit alleging patent infringement.

Beerware is a tongue-in-cheek term for software released under a very relaxed license. It provides the end user with the right to use a particular program.

The Common Development and Distribution License (CDDL) is a free and open-source software license, produced by Sun Microsystems, based on the Mozilla Public License (MPL). Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary. In 2005 the Open Source Initiative approved the license. The Free Software Foundation (FSF) considers it a free software license, but one which is incompatible with the GNU General Public License (GPL).

Free and open-source software Software whose source code is available and which is permissively licensed

Free and open-source software (FOSS) is software that is both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.

A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries 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.

WTFPL License for permissive use of intellectual property rights

WTFPL is a permissive free software license, compatible with the GNU GPL. 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.

License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem negatively by the burden of increasingly complex license selection, license interaction, and license compatibility considerations.

License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.

GNU Affero General Public License Free software license based on the AGPLv1 and GPLv3

The GNU Affero General Public License is a free, copyleft license published by the Free Software Foundation in November 2007, and based on the GNU General Public License, version 3 and the Affero General Public License.

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.

GNU General Public License Series of free software licenses

The GNU General Public License is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and were originally written by the founder of the Free Software Foundation (FSF), Richard Stallman, for the GNU Project. The license grant the recipients of a computer program the rights of the Free Software Definition. These GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. It is more restrictive than the Lesser General Public License and even further distinct from the more widely used permissive software licenses BSD, MIT, and Apache.

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.

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