Various Licenses and Comments about Them
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Various Licenses and Comments about Them
Table of Contents
This page is maintained by the Free Software Foundation's Licensing and Compliance Lab. You can support our efforts by
to the FSF. Have a question not answered here? Check out some of our other
or contact the Compliance Lab at .
Introduction
We classify a license according to certain key criteria:
Whether it qualifies as a
Whether it is a
Whether it is
Unless otherwise specified, compatible licenses are
compatible with both GPLv2 and GPLv3.
Whether it causes any particular practical problems.
We try to list the most commonly encountered free software license on
this page, but
we'll try our best to answer
questions about free software licenses whether or not they are listed
The licenses are more or less in alphabetical order within each
If you believe you have found a violation of one of our licenses,
please refer to our .
If you've started a new project and you're not sure what license to
details our
recommendations in an easy-to-follow guide.
If you have questions about free software licenses, you can email
Because our resources are limited, we do not answer questions that are
meant to assist proprietary software development or distribution, and
you'll likely get an answer faster if you ask a specific question that
isn't already covered here or in .
who want to help answer licensing questions.
If you are contemplating writing a new license, please also contact
us at &licensing@fsf.org&. The
proliferation of different free software licenses is a significant
problem in the free software community today, both for users and
developers.
We will do our best to help you find an existing free
software license that meets your needs.
If you are wondering what license a particular software package is using,
please visit the .
The Free Software Directory catalogues over 6000 free software packages and
their licensing information.
Software Licenses
GPL-Compatible Free Software Licenses
The following licenses qualify as free software licenses, and
with the .
This is the latest version of the GNU GPL: a free software license, and
a copyleft license.
We recommend it for most software packages.
Please note that GPLv3 is not compatible with GPLv2 by itself.
However, most software released under GPLv2 allows you to use the
terms of later versions of the GPL as well.
When this is the case,
you can use the code under GPLv3 to make the desired combination.
learn more about compatibility between GNU licenses,
This is the previous version of the GNU GPL: a free software license, and
a copyleft license.
We recommend
for most software.
Please note that GPLv2 is, by itself, not compatible with GPLv3.
However, most software released under GPLv2 allows you to use the
terms of later versions of the GPL as well.
When this is the case,
you can use the code under GPLv3 to make the desired combination.
learn more about compatibility between GNU licenses,
This is the latest version of the LGPL: a free software license, but not
a strong copyleft license, because it permits linking with nonfree
It is compatible with GPLv3.
We recommend it for special circumstances
Please note that LGPLv3 is not compatible with GPLv2 by itself.
However, most software released under GPLv2 allows you to use the
terms of later versions of the GPL as well.
When this is the case,
you can use the code under GPLv3 to make the desired combination.
learn more about compatibility between GNU licenses,
This is the previous version of the LGPL: a free software license,
but not a strong copyleft license, because it permits linking with
nonfree modules.
It is compatible with GPLv2 and GPLv3.
generally recommend , .
To learn more about how LGPLv2.1 is
compatible with other GNU licenses,
This is a free software, copyleft license.
Its terms effectively
consist of the terms of GPLv3, with an additional paragraph in section 13
to allow users who interact with the licensed software over a network to
receive the source for that program.
We recommend that developers consider
using the GNU AGPL for any software which will commonly be run over a
Please note that the GNU AGPL is not compatible with GPLv2.
also technically not compatible with GPLv3 in a strict sense: you
cannot take code released under the GNU AGPL and convey or modify it
however you like under the terms of GPLv3, or vice versa.
you are allowed to combine separate modules or source files released
under both of those licenses in a single project, which will provide
many programmers with all the permission they need to make the
programs they want.
See section 13 of both licenses for
This is a lax, permissive free software license, compatible with
the GNU GPL, which we recommend GNU packages use for README and other
small supporting files.
All developers can feel free to use it in
similar situations.
Older versions of this license did not have the second sentence with
the express warranty disclaimer.
This same analysis applies to both
This is a free software license, compatible with version 3 of the
Please note that this license is not compatible with GPL version 2,
because it has some requirements that are not in that GPL version.
These include certain patent termination and indemnification
provisions.
The patent termination provision is a good thing, which
is why we recommend the Apache 2.0 license for substantial programs
over other lax permissive licenses.
This license is a free software license, compatible with the GPL
thanks to the relicensing option in section 4(c)(ii).
This license is a free software license, compatible with the GPL.
is the minimal set of changes needed to correct the vagueness of the Artistic License 1.0.
(a.k.a. the Sleepycat Software Product License)
This is a free software license, compatible with the GNU GPL.
This is a lax, permissive non-copyleft free software license,
compatible with the GNU GPL.
This is the original BSD license, modified by removal of the
advertising clause.
It is a lax, permissive non-copyleft free
software license, compatible with the GNU GPL.
This license is sometimes referred to as the 3-clause BSD license.
The modified BSD license is not bad, as lax permissive licenses go,
though the Apache 2.0 license is preferable.
However, it is risky to
recommend use of &the BSD license&, even for special cases
such as small programs, because confusion could easily occur and lead
to use of the flawed .
To avoid this risk, you can suggest the X11 license
The X11 license and the modified BSD license are
more or less equivalent.
However, the Apache 2.0 license is better for substantial programs,
since it prevents patent treachery.
CC0 is a public domain dedication from Creative Commons.
work released under CC0 is dedicated to the public domain to the
fullest extent permitted by law.
If that is not possible for any
reason, CC0 also provides a lax, permissive license as a fallback.
Both public domain works and the lax license provided by CC0 are
compatible with the GNU GPL.
If you want to release your work to the public domain, we recommend
you use CC0.
The CeCILL is a free software license, explicitly compatible with the
The text of the CeCILL uses a couple of biased terms that ought to be
avoided: &intellectual property&
this decision
was unfortunate, because reading the license tends to spread the
presuppositions of those terms.
However, this does not cause any
particular problem for the programs released under the CeCILL.
Section 9.4 of the CeCILL commits the program's developers to certain
forms of cooperation with the users, if someone attacks the program
with a patent.
You might look at that as a probl
however, if you are sure you would want to cooperate with the users in
those ways anyway, then it isn't a problem for you.
This is a free software license, compatible with both GPLv2 and
It is based on the , and adds a term expressly stating it does not grant you
any patent licenses.
Because of this, we encourage you to be careful
about using softwar you should first consider
whether the licensor might want to sue you for patent infringement.
If the developer is refusing users patent licenses to set up a trap
for you, it would be wise to avoid the program.
This is a lax, permissive non-copyleft free software license,
compatible with the GNU GPL.
It is very similar to the X11 license.
The eCos license version 2.0 is a GPL-compatible free software
It consists of the GPL, plus an exception allowing linking to
software not under the GPL.
This license has the same disadvantages
as the LGPL.
This is a free software license, and it is compatible with
I the scope of the patent license has changed so that when
an organization's employee works on a project, the organization
does not have to license all of its patents to recipients.
patent license and the indemnification clause in section&9 make
this license incompatible with GPLv2.
This is a free software license, compatible with the GNU GPL.
releases of the Eiffel license are not compatible with the
This is a lax, permissive non-copyleft free software license,
compatible with the GNU GPL.
This is a lax, permissive non-copyleft free software license,
compatible with the GNU GPL.
It is sometimes ambiguously referred to as
the MIT License.
For substantial programs it is better to use the Apache 2.0 license
since it blocks patent treachery.
This is the original BSD license with the advertising clause and
another clause removed.
(It is also sometimes called the
&2-clause BSD license&.)
It is a lax, permissive
non-copyleft free software license, compatible with the GNU GPL.
Our comments about the
apply to this license too.
This is a free software license, and compatible with GPLv3.
some attribution requirements which make it incompatible with
This is a lax, permissive, and weak free software license that is
compatible with the GPL. It is similar to the license of Python 1.6a2 and earlier versions.
This is a free software license and is GPL compatible.
This is a free software license, and GPL-compatible.
The author has
explained to us that the GPL's options for providing source all mean the
source has been &made available publicly& in their
This is a free software license, and compatible with the GNU GPL.
The authors have assured us that developers who document changes as
required by the GPL will also comply with the similar requirement in
this license.
An &informal license& means a statement such as
&do whatever you like with this& or &you can
redistribute this code and change it.&
In the United States, these licenses are supposed to be interpreted
based on what the author seems to intend.
So they probably mean what
they appear to mean.
That would make them non-copyleft free software
licenses and compatible with the GNU GPL.
However, an unlucky choice
of wording could give it a different meaning.
However, many other countries have a more rigid approach to
copyright licenses.
There is no telling what courts in those
countries might decide an informal statement means.
Courts might
even decide that it is not a license at all.
If you want your code to be free, don't invite gratuitous trouble
for your users.
Please choose and apply an established free software
that we suggest you follow.
This is a free software license, compatible with the GNU GPL.
This is a lax, permissive free software license, and compatible
with the GNU GPL.
This license is sometimes also known as the OpenBSD License,
although there is one minor difference between the two licenses. The
OpenBSD license was updated to remove the ambiguous term:
&and/or&. The ISC license provides recipients with
&Permission to use, copy, modify, and/or distribute this
software&&, whereas the OpenBSD license provides
recipients with &Permission to use, copy, modify, and
distribute&&.
At the time the ISC license was released, the use of
&and/or& construct was a concern because it is similar
language used in the license of Pine that the University of Washington
later claimed prohibited people from distributing modified versions of
the software. However, ISC has told us they do not share the
University of Washington's interpretation, and we have every reason to
believe them.
Thus, there's no reason to avoid software released
under this license.
However, to help make sure this language cannot
cause any trouble in the future, we encourage developers to choose a
different license for their own works.
are similarly
permissive and brief.
This is a free software license.
Section 3.3 provides indirect
compatibility between this license and the GNU GPL version 2.0, the
GNU LGPL version 2.1, the GNU AGPL version 3, and all later versions
of those licenses.
When you receive work under MPL 2.0,
you may make a &Larger Work& that combines that work with
work under those GNU licenses.
When you do, section 3.3 gives
you permission to distribute the MPL-covered work under the terms of
the same GNU licenses, with one condition: you must make sure that the
files that were originally under the MPL are still available under the
MPL's terms as well.
In other words, when you make a combination this
way, the files that were originally under the MPL will be dual
licensed under the MPL and the GNU license(s).
The end result is that
the Larger Work, as a whole, will be covered under the GNU license(s).
People who receive that combination from you will have the option to
use any files that were originally covered by the MPL under that
license's terms, or distribute the Larger Work in whole or in part
under the GNU licenses' terms with no further restrictions.
It's important to understand that the condition to distribute files
under the MPL's terms only applies to the party that first creates and
distributes the Larger Work.
If it applied to their recipients as well, it
would be a further restriction and incompatible with the GPL and AGPL.
That said, when you make contributions to an existing project, we usually
even when you're not required to do so.
If you receive a work under a GNU
license where some files are also under the MPL, you should only remove the
MPL from those files when there's a strong reason to justify it.
Check the license notices on the MPL-covered software before you make
a Larger Work this way.
Parties who release original work under
MPL 2.0 may choose to opt out of this compatibility by
including a sentence in the license notices that says that the work is
&Incompatible With Secondary Licenses.& Any software that
includes this notice is not compatible with the GPL
Software under previous versions of the MPL can be upgraded to version
2.0, but any software that isn't already available under one of the
listed GNU licenses must be marked as Incompatible With Secondary
This means that software that's only available under
previous versions of the MPL is still incompatible with the GPL and AGPL.
This license is based on the terms of the
It is a lax,
permissive non-copyleft free software license, compatible with the GNU
License of Netscape JavaScript
This is the disjunction of the
of that, it is a free software license, compatible with the GNU GPL, but
not a strong copyleft.
This is a permissive non-copyleft free software license that is
compatible with the GNU GPL.
This license is the disjunction of the Artistic License 1.0 and the GNU GPL&in other words,
you can choose either of those two licenses.
It qualifies as a free
software license, but it may not be a real copyleft.
It is compatible
because the GNU GPL is one of the alternatives.
We recommend you use this license for any Perl 4 or Perl 5 package
you write, to promote coherence and uniformity in Perl programming.
Outside of Perl, we urge you not it is better to
use just the GNU GPL.
Being in the public dom rather, it means the
material is not copyrighted and no license is needed.
Practically
speaking, though, if a work is in the public domain, it might as well
have an all-permissive non-copyleft free software license.
domain material is compatible with the GNU GPL.
If you want to release your work to the public domain, we encourage
you to use formal tools to do so.
We ask people who make small
contributions to GNU to si that's one solution.
If you're working on a project that doesn't have formal contribution
policies like that,
is a good tool that anyone
It formally dedicates your work to the public domain, and
provides a fallback license for cases where that is not legally
This is a free software license and is compatible with the GNU GPL.
Please note, however, that intermediate versions of Python (1.6b1,
through 2.0 and 2.1) are under a different license (see below).
This is a free software license and is compatible with the GNU GPL.
Please note, however, that newer versions of Python are under other
licenses (see above and below).
This is a free software license, compatible with the GPL via an
explicit dual-licensing clause.
The SGI Free Software License B version 2.0 is a free software
It is essentially identical to the , with an optional alternative way of providing license
Previous versions of the SGI Free Software License B were not free
software licenses, despite their name.
However, they all included
clauses that allow you to upgrade to new versions of the license, if you
choose to do so.
As a result, if a piece of software was released under
any version of the SGI Free License B, you can use it under the terms of
this free version.
This is a lax, permissive non-copyleft free software license,
compatible with the GNU GPL.
This is a license that Unicode, Inc. has applied to the Unicode
Character Database&various data files that developers can use to
help implement the Unicode standard in their own programs.
lax permissive license, compatible with all versions of the GPL.
If you want to use files covered by this License Agreement in your
own software, that shouldn't be any problem, but we recommend that
you also include a full copy of its text.
Some of the files contain
alternative license terms which are nonfree, or no licensing
information at all, so including a copy of the License Agreement
will help avoid confusion when others want to distribute your
Of course, you'll also need to follow the conditions in
this License Agreement for distributing the files, but those are
very straightforward.
Please take care to ensure that the files you are using are covered
by this License Agreement.
Other files published by Unicode,
Inc. are covered by the Unicode Terms of Use, a different, nonfree
license that appears on the same page but covers different files.
short explanation at the top of this License Agreement details
which files it covers.
Please do not use this License Agreement for your own software.
you want to use a lax permissive license for your project, please use
for a small program and the
Apache 2.0 license for a substantial program.
These are far more
common, and widely recognized in the free software community.
This is a lax, permissive non-copyleft free software license, compatible
with the GNU GPL. The license does provide the ability to license
patents along with the software work, however, we still recommend the
Apache 2.0 license for avoiding patent treachery when choosing to put
your work under a lax license.
The Unlicense is a public domain dedication.
A work released
under the Unlicense is dedicated to the public domain to the fullest
extent permitted by law, and also comes with an additional lax
license that helps cover any cases where the dedication is inadequate.
Both public domain works and the lax license provided by the
Unlicense are compatible with the GNU GPL.
If you want to release your work to the public domain, we recommend
CC0 also provides a public domain
dedication with a fallback license, and is more thorough and
mature than the Unlicense.
This is a free software license, partially copyleft but not
really. It is compatible with the GPL, by an explicit conversion
This is a free software license and is GPL compatible.
Google's WebM implementation is covered by the Modified BSD License.
Google also provides a
separate patent license (confusingly called an &Additional IP
Rights Grant&) for patents that Google owns or controls that are
necessarily infringed by their implementation of WebM.
GPL-covered
software can be distributed in compliance with this license's terms: it
allows distributors to exercise all of the rights granted by the GPL,
while fulfilling all its conditions.
Thus, all of WebM's license is
free and GPL-compatible.
This is a lax permissive non-copyleft free software license,
compatible with the GNU GPL.
We do not recommend this license.
If you want a lax permissive
license for a small program, we recommend
A larger program usually
but if you are set on using a lax permissive
license for one, we recommend the Apache 2.0 license since it protects
users from patent treachery.
WxWidgets Library License
The WxWidgets license is a GPL-compatible free software license. It
consists of the
or any later version, plus an additional permission
allowing binary distributions that use the library to be licensed
under terms of the distributor's choice (including proprietary).
is a weak copyleft, even weaker than the LGPL, so we recommend
WxWindows Library License
An older name for the .
This is a lax permissive non-copyleft free software license,
compatible with the GNU GPL.
Older versions of XFree86 used the same
license, and some of the current variants of XFree86 also do.
versions of XFree86 are distributed under the XFree86 1.1 license.
This license is sometimes called the MIT license, but that
term is misleading, since MIT has used many licenses for
This is a fine license for a small program.
A larger program
but if you are set on a lax permissive
license for one, we recommend the Apache 2.0 license since it protects
users from patent treachery.
This is a lax, permissive non-copyleft free software license,
compatible with version 3 of the GPL.
Please note that this license is incompatible with version 2 of the GPL,
because of its requirements that apply to all documentation in the
distribution that contain acknowledgements.
There are currently several variants of XFree86, and only some of
them use this license.
Some continue to use the X11 license.
This is a free software license, and compatible with the GPL.
This is a lax, permissive non-copyleft free software license
which is compatible with the GNU GPL.
GPL-Incompatible Free Software Licenses
The following licenses
licenses, but
with the .
The Affero General Public License is a free software license,
copyleft, and incompatible with the GNU GPL.
It consists of the GNU GPL
version 2, with one additional section that Affero added with FSF
The new section, 2(d), covers the distribution of application
programs through web services or computer networks.
This license has be please use that instead.
The Academic Free License is a free software license, not copyleft, and
incompatible with the GNU GPL.
Recent versions contain contract clauses
similar to the , and should be
avoided for the same reasons.
This is a permissive non-copyleft free software license.
It has a few
requirements that render it incompatible with the GNU GPL, such as strong
prohibitions on the use of Apache-related names.
This is a lax, permissive non-copyleft free software license with an
advertising clause.
This creates practical problems like
those of the original BSD license, including incompatibility with the GNU
This is a free software license, incompatible with the GNU GPL.
recommend that you not use this license for new software that you write,
but it is ok to use and improve the software released under this
This is a free software license, but incompatible with the GPL,
for the same reasons as the .
This license is also sometimes called the
&4-clause BSD license&.
This is a lax, permissive non-copyleft free software license with
a serious flaw: the &obnoxious BSD advertising clause&.
that is, it does not render the software nonfree.
But it does cause practical problems,
including incompatibility with the GNU GPL.
We urge you not to use the original BSD license for software you
If you want to use a lax, permissive non-copyleft free
software license, it is much better to use the modified BSD license, the X11 license
or the Expat license.
Even better, for a substantial program,
use the Apache 2.0 license since it takes action against patent treachery.
However, there is no reason not to use programs that have been released
under the original BSD license.
The CeCILL-B is a free software license. It is incompatible with the
GPL because it has requirements that are not present in the GPL. The
credit requirements in section 5.3.4 exceed those of the GPL. It also
has a strange requirement that you use your &best efforts&
to get third parties to agree &to comply with the obligations set
forth in this Article.&
Please do not release software under this license.
The CeCILL-C is a free software license with a weak copyleft
somewhat like the .
It is incompatible with the GNU GPL because it does not
contain the explicit GPL-compatibility clause of
Please do not release software under this license.
This is a free software license.
It has a weak per-file copyleft
(like version 1 of the Mozilla Public License) which makes it
incompatible with the .
means a module covered by the GPL and a module covered by the CDDL
cannot legally be linked together.
We urge you not to use the CDDL
for this reason.
For an illustrative example of why you should not combine
CDDL-licensed works with the GPL-licensed works, see the FSF's
statement, .
Also unfortunate in the CDDL is its use of the term &intellectual property&.
This is a free software license.
It is based on the Mozilla Public License version 1, and is incompatible with the GPL
for the same reasons: it has several requirements for modified versions
that do not exist in the GPL.
It also requires you to publish the
source of the program if you allow others to use it.
This is a free software license.
Unfortunately, its weak copyleft
and choice of law clause make it incompatible with the GNU GPL.
Recent versions of Condor (from 6.9.5 on) are released under the Apache License 2.0.
Only older versions of Condor
use this license.
The Condor Public License is a free software license.
couple of requirements that make it incompatible with the GNU GPL,
including strong restrictions on the use of Condor-related names, and
requires redistributors to &represent and warrant& that
they will comply with United States export laws.
(If it made
compliance an actual condition of the license, it would not be a free
software license.)
The Eclipse Public License is similar to the Common Public License, and our
comments on the CPL apply equally to the EPL.
The only change is that
the EPL removes the broader patent retaliation language regarding patent
infringement suits specifically against Contributors to the EPL'd
In terms of GPL compatibility, the Eclipse Public License version
2.0 is essentially equivalent to version 1.0. The only change is that
it explicitly offers the option of designating the GNU GPL version 2
or later as a &secondary license& for a certain piece of
If an initial contributor releases a specific piece of code and
designates GNU GPL version 2 or later as a secondary license, that
provides explicit compatibility with those GPL versions for that
code. (Doing so is roughly equivalent, for users, to releasing that
piece of code under a dual license, EPL | GPL.) However, the EPL2
without this designation remains incompatible with the GPL.
This is a free software license.
By itself, it has a copyleft
comparable to the GPL's, and incompatible with it.
However, it gives
recipients ways to relicense the work under the terms of other
selected licenses, and some of those&the
in particular&only provide a weaker copyleft.
Thus, developers can't rely on this license to provide a strong
The EUPL allows relicensing to GPLv2, because that is listed as one
of the alternative licenses that users may convert to.
indirectly, allows relicensing to GPL version 3, because there is a
way to relicense to the CeCILL v2, and the CeCILL v2 gives a way to
relicense to any version of the GNU GPL.
To do this two-step relicensing, you need to first write a piece of
code which you can license under the CeCILL v2, or find a
suitable module already available that way, and add it to the
Adding that code to the EUPL-covered program provides
grounds to relicense it to the CeCILL v2.
Then you need to write a
piece of code which you can license under the GPLv3+, or find a
suitable module already available that way, and add it to the program.
Adding that code to the CeCILL-covered program provides grounds to
relicense it to GPLv3+.
This is a free software license, incompatible with the GNU GPL.
This is a free software license.
Unfortunately, it has a choice of law
clause which makes it incompatible with the GNU GPL.
The license is a free software license, incompatible with the GPL.
It permits relicensing under a certain class of licenses, those which
include all the requirements of the Jabber license.
The GPL is not a
member of that class, so the Jabber license does not permit relicensing
under the GPL.
Therefore, it is not compatible.
We have not written a full analysis of this license, but it is a free
software license, with less stringent requirements on distribution than
LPPL&1.2 (described next).
It is still incompatible with the GPL
because some modified versions must include a copy of or pointer to an
unmodified version.
This license is an incomplete statement of the distribution terms
for LaTeX.
As far as it goes, it is a free software license, but
incompatible with the GPL because it has
many requirements that are not in the GPL.
This license contains complex and annoying restrictions on how to
publish a modified version, including one requirement that falls just
barely on the good side of the line of what is acceptable: that any
modified file must have a new name.
The reason this requirement is acceptable for LaTeX is that TeX has
a facility to allow you to map file names, to specify &use file
bar when file foo is requested&.
With this facility, the
requiremen without the facility, the same
requirement would be a serious obstacle, and we would have to conclude
it makes the program nonfree.
This condition may cause trouble with some major modifications.
For example, if you wanted to port an LPPL-covered work to another
system that lacked a similar remapping facility, but still required
users to request this file by name, you would need to implement a
remapping facility too to keep this software free.
That would be a
nuisance, but the fact that a license would make code nonfree if
transplanted into a very different context does not make it nonfree in
the original context.
The LPPL says that some files, in certain versions of LaTeX, may have
additional restrictions, which could render them nonfree.
reason, it may take some careful checking to produce a version of
LaTeX that is free software.
The LPPL makes the controversial claim that simply having files on a
machine where a few other people could log in and access them in
itself constitutes distribution.
We believe courts would not uphold
this claim, but it is not good for people to start making the claim.
Please do not use this license for any other project.
Note: These comments are for version 1.2 (3 Sep 1999) of the LPPL.
This is a free software license, but it is incompatible with the GNU GPL
because of its choice of law clause.
We recommend that you not use this
license for new software that you write, but it is ok to use and improve
Plan&9 under this license.
This is a f it has a copyleft that is not
strong, but incompatible with the GNU GPL.
We urge you not to use
the Ms-PL for this reason.
This is a free software license.
It's based on the Microsoft Public License, and has an additional clause
to make the copyleft just a little bit stronger.
It's also incompatible
with the GNU GPL, and we urge you not to use the Ms-RL for this
This is a free software license which is n
unlike the , it has some complex
restrictions that make it incompatible with
That is, a module
covered by the GPL and a module covered by the MPL cannot legally be
linked together.
We urge you not to use the MPL 1.1 for this
However, MPL 1.1 has a provision (section 13) that allows a program
(or parts of it) to offer a choice of another license as well.
of a program allows the GNU GPL as an alternate choice, or any other
GPL-compatible license as an alternate choice, that part of the program
has a GPL-compatible license.
MPL version 2.0 has a number of improvements, including
GPL-compatibility by default.
for details.
This is a free software license that is essentially the same as the
Mozilla Public License version 1.1.
Like the MPL, the NOSL has some
complex restrictions that make it incompatible with the GNU GPL.
is, a module covered by the GPL and a module covered by the NOSL cannot
legally be linked together.
We urge you not to use the NOSL for this
, versions 1.0 and 1.1
This is a free software license, not a strong copyleft, and
incompatible with the GNU GPL.
It consists of the Mozilla Public
License version 1.1 with an added clause that permits Netscape to use
your added code even in their proprietary versions of the
Of course, they do not give you permission to
use their code in the analogous
This is similar to the Mozilla Public License version 1: a free
software license incompatible with the GNU GPL.
This is a permissive non-copyleft free software license with a few
requirements (in sections 4 and 5) that render it incompatible with
the GNU GPL.
Note that the latest version of OpenLDAP has
that is compatible with
the GNU GPL.
We urge you not to use the older OpenLDAP license for software you
However, there is no reason to avoid running programs that have
been released under this license.
The Open Software License is a free software license.
incompatible with the GNU GPL in several ways.
Recent versions of the Open Software License have
a term which requires distributors to try to obtain explicit assent to
the license.
This means that distributing OSL software on ordinary FTP
sites, sending patches to ordinary mailing lists, or storing the
software in an ordinary version control system, is arguably a violation
of the license and would subject you to possible termination of the
Thus, the Open Software License makes it very difficult to
develop software using the ordinary tools of free software development.
For this reason, and because it is incompatible with the GPL, we
recommend that no version of the OSL be used for any software.
We urge you not to use the Open Software License for software you
However, there is no reason to avoid running programs that
have been released under this license.
The license of OpenSSL is a conjunction of two licenses, one called
&OpenSSL License& and the other being the license of SSLeay. You must
follow both.
The combination results in a copyleft free software
license that is incompatible with the GNU GPL.
It also has an
advertising clause like the
We recommend using GNUTLS instead of OpenSSL in software you write.
However, there is no reason not to use OpenSSL and applications that
work with OpenSSL.
This is a free software license but it is incompatible with the GPL.
Section 5 makes
the license incompatible with the GPL.
This license is used by most of PHP4.
It is a non-copyleft free
software license.
It is incompatible with the GNU GPL because it
includes strong restrictions on the use of &PHP& in the
name of derived products.
We recommend that you not use this license for anything except PHP
This is a free software license but is incompatible with the GNU GPL.
The primary incompatibility is that this Python license is governed by the
laws of the State of Virginia, in the USA, and the GPL does not permit
This is a non-copyleft free software license which is incompatible with
the GNU GPL.
It also causes major practical inconvenience, because modified
sources can only be distributed as patches.
We recommend that you avoid using the QPL for anything that you write,
and use QPL-covered software packages only when absolutely necessary.
However, this avoidance no longer applies to Qt itself, since Qt is
now also released under the GNU GPL.
Since the QPL is incompatible with the GNU GPL, you cannot take a
GPL-covered program and QPL-covered program and link them together, no
matter how.
However, if you have written a program that uses QPL-covered library
(called FOO), and you want to release your program under the GNU GPL,
you can easily do that.
You can resolve the conflict for your
program by adding a notice like this to it:
As a special exception, you have permission to link this program
with the FOO library and distribute executables, as long as you
follow the requirements of the GNU GPL in regard to all of the
software in the executable aside from FOO.
You can do this, legally, if you are the copyright holder for the
Add it in the source files, after the notice that says
the program is covered by the GNU GPL.
The RPSL is a free software license that is GPL-incompatible for a
number of reasons: it requires that derivative works be licensed under the
terms of the RPSL, and mandates that any litigation take place in Seattle,
Washington.
This is a free software license, not a strong copyleft, which is
incompatible with the GNU GPL because of details rather than any
major policy.
This is essentially the same as the Mozilla Public License version 1: a free
software license incompatible with the GNU GPL.
Please do not confuse
this with the , which is not a free software license.
This is a copyleft free software license, incompatible with the GPL.
It is incompatible because it places extra restrictions on
redistribution of modified versions that contradict the redistribution
requirements in the GPL.
This is a free software license.
It has a copyleft similar to the
one found in the Mozilla Public License.
It also has a choice of law
clause in section&7.
These features both make the license
GPL-incompatible.
The license also unfortunately uses the term
This license is used by one part of PHP4.
It is a non-copyleft free
software license which is incompatible with the GNU GPL, and has practical problems
like those of the original BSD license.
We recommend that you not use this license for anything you write.
This license is identical to the , except that the license is provided by VMWare instead
of Yahoo!.
Our comments ther this is a
GPL-incompatible, partial copyleft free software license.
This is a lax, fairly permissive non-copyleft free software
license with
like those of the original BSD license, including
incompatibility with the GNU GPL.
We urge you not to use the ZPL version 1 for software you write.
However, there is no reason to avoid running programs that have been
released under this license, such as previous versions of Zope.
GPL-compatible.
Nonfree Software Licenses
The following licenses do not qualify as free software
A nonfree license is automatically incompatible with the GNU GPL.
Of course, we urge you to avoid using nonfree software licenses, and
to avoid nonfree software in general.
There is no way we could list all the known nonfree software
after all, every proprietary software company has its
We focus here on licenses that are often mistaken for free
software licenses but are, in fact, not free software
We have provided links to these licenses when we can do so without
violating our general policy: that we do not make links to sites that
promote, encourage or facilitate the use of nonfree software packages.
The last thing we want to do is give any nonfree program some gratis
publicity that might encourage more people to use it.
For the same
reason, we have avoided naming the programs for which a license is used,
unless we think that for specific reasons it won't backfire.
If source code does not carry a license to give users the four
essential freedoms, then unless it has been explicitly and validly
placed in the public domain, it is not free software.
Some developers think that code with no license is
automatically .
is not true under today' rather, all copyrightable
works are copyrighted by default.
This includes programs.
license to grant users freedom, they don't have any.
countries, users that download code with no license may infringe
copyright merely by compiling it or running it.
In order for a program to be free, its copyright holders must
explicitly grant users the .
The document with which they do so is called
a free software license.
This is what free software
licenses are for.
Some countries allow authors to put code in the public domain, but
that requires explicit action.
If you wish to do that, the method we
recommend is to use , which also works in other
countries by putting on a license that is more or less equivalent to
public domain.
However, in most cases it
to assure that freedom reaches all users of the
Code written by employees of the US government is a special
exception, since US copyright law explicitly puts that in the public
but this does not apply to works that the US pays a company to
It also does not apply to other countries, many of which do
allow the state to have a copyright on government writings.
Despite its name, this is not a free software license because it
does not allow charging for distribution, and largely prohibits simply
packaging software licensed under it with anything for which a charge
Versions 1.0, 1.1 and 1.2 are not free
software licenses.
don't use these licenses, and we urge you to avoid any software that has
been released under them.
is a free software license.
We cannot say that this is a free software license because it is too
some passages are too clever for their own good, and their meaning is
not clear.
We urge you to avoid using it, except as part of
The AT&T Public License is a nonfree license.
It has several
serious problems:
The patent license is voided by any modification, no matter how
small, of the pertinent code.
You must demand a written agreement when you distribute the
sources or patches.
It requires notifying AT&T if you distribute a patch.
Your license can be terminated through no fault of yours, under
section 8/3.
It makes compliance with export control laws a condition
of the license.
Some versions of the license require you to provide support.
Some versions of the license say you cannot sell a copy of the
software for more than the expense of distribution.
The license has two other obnoxious features:
It has a very broad reverse license to AT&T, which goes far beyond
the use of your code, even your code modified.
It asserts one needs a license from AT&T to make a link to their
This is not an immediate practical problem, since the
license says it gives permission to make such a link.
(Anyway, people
shouldn't make links to sites about nonfree software.)
a claim should not be made or propagated.
The Code Project Open License is not a free software license.
Section 5.6 restricts how you can use the work.
Section 5.4 prohibits
commercial distribution of the software by itself&and depending
on how you read section 3.4, you may not have permission to distribute
the software by itself at all.
This was the old license of eCos.
It is not a free software
license, because it requires sending every published modified version
to a specific initial developer.
There are also some other words in
this license whose meaning we're not sure of that might also be
problematic.
under the GNU GPL with
additional permission for linking with nonfree programs.
This license is non-free because of Article 3, which arguably
includes a requirement not to violate the license of any
program that the user runs&even proprietary programs.
The GPL-PA (whose original name in Portuguese is
&Licen&a P&blica Geral para
Administra&&o P&blica&) is nonfree for
several reasons:
It permits use only in &normal circumstances&.
It does not allow distribution of source code without binaries.
Its permissions lapse after 50 years.
This is not a free software license, because it restricts what jobs
people can use the software for, and restricts in substantive ways what
jobs modified versions of the program can do.
The Jahia Community Source License is not a free software license.
of the source code is limited to research purposes.
This is the license of the original implementation of the JSON data
interchange format.
This license uses the Expat license as a base,
but adds a clause mandating: &The Software shall be used for Good, not
This is a restriction on usage and thus conflicts with freedom
The restriction might be unenforcible, but we cannot presume that.
Thus, the license is nonfree.
ksh93 used to be shipped with an original license that was not a free
software license.
One reason for this is that it required that all changes
be sent to the developer.
The lha license must be considered nonfree because it is so vague that
you cannot be sure what permissions you have.
This license does not permit commercial distribution, and only allows
commercial use under certain circumstances.
Microsoft has other licenses which it describes as &Shared
Source&, some of which have different restrictions.
The NASA Open Source Agreement, version 1.3, is not a free software
license because it includes a provision requiring changes to be your
&original creation&.
Free software development depends on
combining code from third parties, and the NASA license doesn't permit
We urge you not to use this license.
In addition, if you are a
United States citizen, please write to NASA and call for the use of a
truly free software license.
This is not a f it has several fatal flaws.
One can't redistribute anything less than the whole program libOVR.
One's distribution rights can be terminated on vague conditions.
Those who make modified versions are required to send them to
Oculus on demand.
Use is allowed only with their product.
New license versions totally supplant old versions, which means
that permissions already given can be withdrawn.
There might be ad after seeing this many,
we stopped looking for more.
This is not a free software license, because it requires sending
every published modified version to a specific initial developer.
There are also some other words in this license whose meaning we're
not sure of that might also be problematic.
The Peer-Production License is not a free software license because
it restricts who can redistribute the program and for what purpose.
It also does not give anyone permission to run the program.
The PPL has several provisions designed specifically for artistic
performances, and we have nothing against i
however, people reportedly advocate its use for software too.
should not be used for software, manuals, or other works that ought to
The license of PINE is not a free software license because it mostly
prohibits the distribution of modified versions.
It also restricts the
media that can be used for selling
Please note that a successor to Pine, Alpine, is released under the Apache License, version 2.0.
This is not a f it lacks essential freedoms such
as the right to make and use private changes.
Of course you should not
use this license, and we urge you to avoid any software that has been
released under it.
A detailed
discussion of this license is also available.
In September 2002 it was observed that the published license for
Plan&9 had been modified, adding more restrictions to it, although
its date still said 09/20/00.
However, a .
The Reciprocal Public License is a nonfree license because of three
1.&It puts limits on prices charged for an initial copy.
2.&It requires notification of the original developer for
publication of a modified version.
3.&It requires publication of
any modified version that an organization uses, even privately.
This is not a free software license because it does not allow
commercial distribution of a modified version.
Thankfully, starting
from version 5.0.0, the Scilab software is free software, released
under CeCILL version&2.
This is not a free software license because it does not allow
commercial redistribution.
In addition, condition 4 substantively
restricts the functionality of modified versions.
Newer versions Scratch software are distributed under the GNU GPL,
but some of those newer version we do not recommend, because they
depend on the proprietary software, Adobe Air.
Despite the name, this is a software license, and it's nonfree
for several reasons:
You must get the licensor's permission before distributing the
It's possible that your license can be terminated if you received
the software from someone who did not obey the license's terms.
The original Squeak license, as applied to software, is not a free
software license because it requires all users in whatever country to
obey US export control laws.
As applied to fonts, it also does not
permit modification.
In addition, it has a requirement for users to indemnify the
developer, which is enough to make many users think twice about using it
Recent versions of Squeak (from 4.0 on) are released under an
with some portions of the code
under the .
This is not a f it lacks essential freedoms such
as publication of modified versions.
Please don't use this license, and
we urge you to avoid any software that has been released under
This is not a free software license.
The license prohibits
redistribution, prohibits commercial use of the software, and can be
This is not a free software license. It requires you to publish the
source code publicly whenever you &Deploy& the covered
software, and &Deploy& is defined to include many kinds of
private use.
This license requires all recipients to proactively help the licensor
enforce its trademarks.
This is an unreasonable condition to place on
users' rights, so the license is nonfree.
It also has other practical
problems: some of the requirements are vague, and it uses the term &intellectual
property&.
Despite the name, it is not clear whether this license would
qualify as &open source&.
However, our judgment of it is
not based on that.
This license is nonfree for several reasons.
It says that if you
don't understand the license you may not use the program.
conditions on allowing others to run your copy.
It puts conditions on
separate programs that &depend on& Truecrypt.
trademark condition applies to &associated materials&.
There are other points in the license which seem perhaps
unacceptable, and in our uncertainty about them we delayed in posting
our evaluation.
We have posted it now to explain why we do not mourn
the demise of Truecrypt.
The University of Utah Public License is a nonfree license because
it does not allow commercial redistribution.
It also purports to
restrict commercially running the software and even commercially giving
consultation about it.
Those restrictions are probably not legally
enforceable under US copyright law, but they might
even asserting them is outrageous.
The use of this license by the University of Utah exemplifies a dangerous
trend for universities to restrict knowledge rather than
contributing it to the public.
If a university tries to impose a license like this on the software
you are writing, don't give up hope.
With persistence
and firmness, and some forethought, it is possible to prevail over
money-grabbing university administrators.
The earlier you raise the issue, the better.
This is not a free software license.
The license prohibits
distribution for a fee, and that makes it impossible for the software to
be included in the many CD-ROM free software collections that are sold
by companies and by organizations.
There may be another problem in section 2a, but a word seems to be
missing there, so it is hard to be sure what meaning is really
(The YaST software itself no longer uses this nonfree YaST
happily, it is now free software, released under the GNU GPL.)
Licenses For Documentation
Free Documentation Licenses
The following licenses qualify as free
documentation licenses.
This is a license intended for use on
copylefted .
for all GNU
It is also suitable for other kinds of useful works (such as
textbooks and dictionaries, for instance).
Its applicability is not
limited to textual works (&books&).
This is a permissive non-copyleft free documentation license that is
compatible with the GNU FDL.
This is a free documentation license that is incompatible with the
It is incompatible because Section&(2c) says &You
add no other terms or conditions to those of this License&, and
the GNU FDL has additional terms not accounted for in the Common
Documentation License.
This license can be used as a free documentation
It is a copyleft free documentation license
provided the copyright holder does not exercise any of
the &LICENSE OPTIONS& listed in Section VI of the license.
But if either of the options is invoked, the license becomes
In any case, it is incompatible with the GNU FDL.
This creates a practical pitfall in using or recommending this
license: if you recommend &Use the Open Publication License, Version
1.0 but don't enable the options&, it would be easy for the second
half of that recommendat someone might use the
license with the options, making a manual nonfree, and yet think he
or she is following your advice.
Likewise, if you use this license without either of the options to
make your manual free, someone else might decide to imitate you, then
change his or her mind about the options thinking that that is just a
the result would be that his or her manual is nonfree.
Thus, while manuals published under this license do qualify as free
documentation if neither license option was used, it is better to use the
GNU Free Documentation License and avoid the risk of leading someone else
Please note that this license is not the same as the Open Content License.
These two licenses are frequently
confused, as the Open Content License is often referred to as the
For clarity, it is better not to use the
abbreviation &OPL& for either license.
It is worth spelling
their names in full to make sure people understand what you say.
Nonfree Documentation Licenses
The following licenses do not qualify
as free documentation licenses:
This license does not qualify as free, because there are restrictions on
charging money for copies.
We recommend you do not use this license.
Please note that this license is not the same as the Open Publication License.
The practice of
abbreviating &Open Content License& as &OPL&
leads to confusion between them.
For clarity, it is better not to use
the abbreviation &OPL& for either license.
It is worth
spelling their names in full to make sure people understand what you
This license does not qualify as free, because there are
restrictions on charging money for copies.
Thus, we recommend you do
not use this license for documentation.
In addition, it has a drawback for any sort of work: when a
modified version has many authors, in practice getting permission for
commercial use from all of them would become infeasible.
This license does not qualify as free, because there are
restrictions on distributing modified versions.
We recommend you do
not use this license for documentation.
Licenses for Other Works
Licenses for Works of Practical Use
besides Software and Documentation
The GNU GPL can be used for general data which is
not software, as long as one can determine what the definition of
&source code& refers to in the particular case.
As it turns
out, the DSL (see below) also requires that you determine what the
&source code& is, using approximately the same definition
that the GPL uses.
The GNU FDL is recommended for textbooks and teaching materials for
all topics.
(&Documentation& simply means textbooks and
other teaching materials for using equipment or software.)
recommend the GNU FDL for dictionaries, encyclopedias, and any other
works that provide information for practical use.
(a.k.a. CC&BY)
This is a non-copyleft free license that is good for art and
entertainment works, and educational works.
It is compatible with all
versions of the GNU GPL; however, like all CC
licenses, .
Creative Commons publishes many licenses which are
very different.
Therefore, to say that a work &uses a Creative
Commons license& is to leave the principal questions about the
work's licensing unanswered.
When you see such a statement in a work,
please ask the author to change the work to state clearly and
visibly which of the Creative Commons license it uses.
someone proposes to &use a Creative Commons license& for a
certain work, it is vital to ask &Which Creative Commons
license?& before proceeding any further.
(a.k.a. CC&BY-SA)
This is a copyleft free license that is good for artistic and
entertainment works, and educational works.
Like all CC
licenses, .
CC BY-SA 4.0 is one-way compatible with the GNU GPL version 3: this
means you may license your modified versions of CC BY-SA 4.0 materials
under GNU GPL version 3, but you may not relicense GPL 3 licensed
works under CC BY-SA 4.0.
Because Creative Commons lists only version 3 of the GNU GPL on
list, it means that you can not license your adapted CC
BY-SA works under the terms of &GNU GPL version 3, or (at your option)
any later version.& However, Section 14 of the GNU GPL version 3
allows licensors to specify a proxy to determine whether future
versions of the GNU GPL can be used. Therefore, if someone adapts a CC
BY-SA 4.0 work and incorporates it into a GNU GPL version 3 licensed
project, they
can specify Creative Commons as their proxy (via http://creativecommons.org/compatiblelicenses)
so that if and when Creative Commons determines that a future version
of the GNU GPL is a compatible license, the adapted and combined work
could be used under that later version of the GNU GPL.
This is a free and copyleft license meant for general data.
Please don't use it for software or documentation, since it is
incompatible with the GNU GPL and with the GNU FDL; however, it is
fine to use for other kinds of data.
This is a free and copyleft license meant for artistic works. It
permits commercial distribution, as any free license must.
copyleft license because any larger work that includes part of the
work you received must be released, as a whole, either under the same
license or under a similar license that meets stated criteria.
don't use it for software or documentation, since it is incompatible
with the GNU GPL and with the GNU FDL.
This is a free and copyleft license meant for data.
incompatible with the GNU GPL. Please don't use it for software or
documentation, since it is incompatible with the GNU GPL and with the
GNU FDL. It makes inconvenient requirements about signing contracts
which try to create an effect like copyleft for data that is not
copyrightable, so we don' however, there is no
reason to avoid using data released this way.
Licenses for Fonts
The licenses below apply to an instantiation of a design in a computer
file, not the artistic design.
As far as we know, an implementation of
a design is always copyrightable.
The legal status of the artistic
design is complex, and varies by jurisdiction.
The GNU GPL can be used for fonts.
However, note
that it does not permit embedding the font in a document unless that
document is also licensed under the GPL.
If you want to allow this, use
exception.
See also this explanatory
essay about the GPL Font Exception.
This is a copyleft free software license, incompatible with the
GPL. Its normal use is for fonts, and in that use, the
incompatibility does not cause a problem.
This license covers the European Computer Modern Fonts and Text
Companion Fonts, commonly used with LaTeX.
Depending on how it is
used, it may be free or not.
If the package says that some fonts in
the package may not be modified, then the package is nonfree.
Otherwise the package is free.
The original fonts have no
restrictions on modification, so they are free.
Much like , this license requires modified versions of the work
to use a name that's different from the name of any prior version.
This is acceptable for work meant to be used with LaTeX, since TeX
allows you to create filename mappings for your programs, but it's
very annoying and could be overly burdensome in other contexts.
This is a copyleft free software license, incompatible with the
GPL. It has an unfortunate condition requiring that derivative works
not use or include the name of the original work as a program name,
font name or file name. This is acceptable for fonts as fonts can be
aliased or renamed using free software tools, but it's very annoying
and could be overly burdensome in other contexts.
The Open Font License (including its original release, version 1.0)
is a free copyleft license for fonts.
Its only unusual requirement is
that when selling the font, you must redistribute it bundled with
some software, rather than alone.
Since a simple Hello World program
will satisfy the requirement, it is harmless.
Neither we nor SIL
recommend the use of this license for anything other than
Licenses for Works stating a Viewpoint (e.g., Opinion or Testimony)
Works that express someone's opinion&memoirs, editorials, and
so on&serve a fundamentally different purpose than works for
practical use like software and documentation.
Because of this, we
expect them to provide recipients with a different set of permissions:
just the permission to copy and distribute the work verbatim.
frequently
in his speeches.
Because so many licenses meet these criteria, we cannot list them
If you are looking for one to use yourself, however, there are
two that we recommend:
This was the license used throughout the GNU web site for many
It is very simple, and especially well-suited to written
This is the license used throughout the GNU and FSF web sites.
This license provides much the same permissions as our verbatim
copying license, but it's much more detailed. We particularly
recommend it for audio and/or video works of opinion.
versions of this license are also OK to use, but we do recommend
upgrading to this version if you can.
Licenses for Designs for Physical Objects
Circuits are meant for practical use, so circuit designs should carry
a free license.
We recommend releasing them under the GNU General
Public License, version 3 or later.
Version 3 was designed for such
3D-printer plans for objects meant for practical use should also be
We recommend the GNU GPL or one of the Creative Commons
licenses that are free: CC-BY, CC-BY-SA, or CC0.
3D-printer plans for decorative object any of the
Creative Commons licenses is ok for them.
&The Free Software Foundation (FSF) is a nonprofit with a worldwide
mission to promote computer user freedom. We defend the rights of all
software users.&
the principal organizational sponsor of the GNU Operating System.
Support GNU and the FSF by buying manuals and gear,
joining the FSF as an associate member, or making
a donation, either directly to the FSF or via
Copyright & , , 2018 Free Software Foundation, Inc.
This page is licensed under a .
20:52:39 $}