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3  <HEAD>  <title>What is free software?
4  <TITLE>The Free Software Definition - GNU Project - Free Software Foundation (FSF)</TITLE>  - GNU Project - Free Software Foundation</title>
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8  <H3>The Free Software Definition</H3>     .note { margin-top: .8em; }
9    }
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11     ALT=" [image of a Philosophical Gnu] "  <meta http-equiv="Keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" />
12     WIDTH="160" HEIGHT="200"></A>  <meta http-equiv="Description" content="Since 1983, developing the free Unix style operating system GNU, so that computer users can have the freedom to share and improve the software they use." />
13    
14  [  <!--#include virtual="/philosophy/po/free-sw.translist" -->
15  <!-- Please keep this list alphabetical -->  <!--#include virtual="/server/banner.html" -->
16  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  
17  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <h2>What is free software?</h2>
18  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  
19  | <A HREF="/philosophy/free-sw.da.html">Danish</A>  <div class="article">
20  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  <h3>The Free Software Definition</h3>
21  | <A HREF="/philosophy/free-sw.html">English</A>  
22  | <A HREF="/philosophy/free-sw.fr.html">French</A>  <blockquote class="note" id="fsf-licensing"><p style="font-size: 80%">
23  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  Have a question about free software licensing not answered here?
24  | <A HREF="/philosophy/free-sw.de.html">German</A>  See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
25  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  and if necessary contact the FSF Compliance Lab
26  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
27  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  </blockquote>
28  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  
29  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  <div class="comment">
30  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  <p>
31  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  The free software definition presents the criteria for whether a
32  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  particular software program qualifies as free software.  From time to
33  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  time we revise this definition, to clarify it or to resolve questions
34  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  about subtle issues.  See the <a href="#History">History section</a>
35  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>  below for a list of changes that affect the definition of free
36  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  software.
37  | <A HREF="/philosophy/free-sw.sv.html">Swedish</A>    </p>
38  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  
39  <!-- Please keep this list alphabetical -->  <p>
40  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  &ldquo;Open source&rdquo; is something different: it has a very
41  ]  different philosophy based on different values.  Its practical
42  <P>  definition is different too, but nearly all open source programs are
43    in fact free.  We explain the
44  We maintain this free software definition to show clearly what must be  difference in <a href="/philosophy/open-source-misses-the-point.html">
45  true about a particular software program for it to be considered  Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
46  free software.  </p>
47    </div>
48  <P>  
49    <p>
50  ``Free software'' is a matter of liberty, not price.  To understand the  &ldquo;Free software&rdquo; means software that respects users'
51  concept, you should think of ``free'' as in ``free speech,'' not as in  freedom and community.  Roughly, it means that <b>the users have the
52  ``free beer.''  freedom to run, copy, distribute, study, change and improve the
53  <P>  software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
54  Free software is a matter of the users' freedom to run, copy,  liberty, not price.  To understand the concept, you should think of
55  distribute, study, change and improve the software.  More precisely,  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
56  it refers to four kinds of freedom, for the users of the software:  &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
57  <P>  software,&rdquo; borrowing the French or Spanish word for
58    &ldquo;free&rdquo; as in freedom, to show we do not mean the software
59  <UL>  is gratis.
60    <LI>The freedom to run the program, for any purpose (freedom 0).  </p>
61    <LI>The freedom to study how the program works, and adapt it to your needs  
62        (freedom 1).   Access to the source code is a precondition for this.  <p>
63    <LI>The freedom to redistribute copies so you can help your neighbor  We campaign for these freedoms because everyone deserves them.  With
64    these freedoms, the users (both individually and collectively) control
65    the program and what it does for them.  When users don't control the
66    program, we call it a &ldquo;nonfree&rdquo; or
67    &ldquo;proprietary&rdquo; program.  The nonfree program controls the
68    users, and the developer controls the program; this makes the
69    program <a href="/philosophy/free-software-even-more-important.html">
70    an instrument of unjust power</a>.
71    </p>
72    
73    <h4> The four essential freedoms</h4>
74    
75    <p>
76    A program is free software if the program's users have the
77    four essential freedoms: <a href="#f1">[1]</a>
78    </p>
79    
80    <ul class="important">
81      <li>The freedom to run the program as you wish,
82          for any purpose (freedom 0).</li>
83      <li>The freedom to study how the program works, and change it so it
84          does your computing as you wish (freedom 1). Access to the source
85          code is a precondition for this.
86      </li>
87      <li>The freedom to redistribute copies so you can help others
88        (freedom 2).        (freedom 2).
89    <LI>The freedom to improve the program, and release your improvements    </li>
90       to the public, so that the whole community benefits    <li>The freedom to distribute copies of your modified versions
91        (freedom 3).   Access to the source code is a precondition for this.        to others (freedom 3).  By doing this you can give the whole
92  </UL>        community a chance to benefit from your changes.
93          Access to the source code is a precondition for this.
94  <P>    </li>
95  A program is free software if users have all of these freedoms.  </ul>
96  Thus, you should be free to redistribute copies, either with or  
97  without modifications, either gratis or charging a fee for  <p>
98  distribution, to <A HREF="#exportcontrol">anyone anywhere</A>.  Being  A program is free software if it gives users adequately all of these
99  free to do these things means (among other things) that you do not  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
100  have to ask or pay for permission.  nonfree distribution schemes in terms of how far they fall short of
101    being free, we consider them all equally unethical.</p>
102    
103    <p>In any given scenario, these freedoms must apply to whatever code
104    we plan to make use of, or lead others to make use of.  For instance,
105    consider a program A which automatically launches a program B to
106    handle some cases.  If we plan to distribute A as it stands, that
107    implies users will need B, so we need to judge whether both A and B
108    are free.  However, if we plan to modify A so that it doesn't use B,
109    only A needs to be free; B is not pertinent to that plan.</p>
110    
111    <p>
112    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.
113    On the contrary, a free program must be available for commercial use,
114    commercial development, and commercial distribution.  This policy is
115    of fundamental importance&mdash;without this, free software could not
116    achieve its aims.
117    </p>
118    
119    <p>
120    We want to invite everyone to use the GNU system, including businesses
121    and their workers.  That requires allowing commercial use.  We hope
122    that free replacement programs will supplant comparable proprietary
123    programs, but they can't do that if businesses are forbidden to use
124    them.  We want commercial products that contain software to include
125    the GNU system, and that would constitute commercial distribution for
126    a price.  Commercial development of free software is no longer
127    unusual; such free commercial software is very important.  Paid,
128    professional support for free software fills an important need.
129    </p>
130    
131    <p>
132    Thus, to exclude commercial use, commercial development or commercial
133    distribution would hobble the free software community and obstruct its
134    path to success.  We must conclude that a program licensed with such
135    restrictions does not qualify as free software.
136    </p>
137    
138    <p>
139    A free program must offer the four freedoms to any would-be user that
140    obtains a copy of the software, who has complied thus far with the
141    conditions of the free license covering the software in any previous
142    distribution of it.  Putting some of the freedoms off limits to some
143    users, or requiring that users pay, in money or in kind, to exercise
144    them, is tantamount to not granting the freedoms in question, and thus
145    renders the program nonfree.
146    </p>
147    
148    <p>
149    You may have paid money to get copies of a free program, or you may
150    have obtained copies at no charge.  But regardless of how you got your
151    copies, you always have the freedom to copy and change the software,
152    even to <a href="/philosophy/selling.html">sell copies</a>.
153    </p>
154    
155    <h3>Clarifying the boundary between free and nonfree</h3>
156    
157    <p>In the rest of this article we explain more precisely how far the
158    various freedoms need to extend, on various issues, in order for a
159    program to be free.</p>
160    
161    <h4>The freedom to run the program as you wish</h4>
162    
163    <p>
164    The freedom to run the program means the freedom for any kind of person
165    or organization to use it on any kind of computer system, for any kind of
166    overall job and purpose, without being required to communicate about it
167    with the developer or any other specific entity.  In this freedom, it is
168    the <em>user's</em> purpose that matters, not the <em>developer's</em>
169    purpose; you as a user are free to run the program for your purposes,
170    and if you distribute it to someone else, she is then free to run it
171    for her purposes, but you are not entitled to impose your purposes on her.
172    </p>
173    
174    <p>
175    The freedom to run the program as you wish means that you are not
176    forbidden or stopped from making it run.  This has nothing to do with what
177    functionality the program has, whether it is technically capable of
178    functioning in any given environment, or whether it is useful for any
179    particular computing activity.</p>
180    
181    <p>For example, if the code arbitrarily rejects certain meaningful
182    inputs&mdash;or even fails unconditionally&mdash;that may make the
183    program less useful, perhaps even totally useless, but it does not
184    deny users the freedom to run the program, so it does not conflict
185    with freedom 0.  If the program is free, the users can overcome the
186    loss of usefulness, because freedoms 1 and 3 permit users and
187    communities to make and distribute modified versions without the
188    arbitrary nuisance code.</p>
189    
190    <p>&ldquo;As you wish&rdquo; includes, optionally, &ldquo;not at
191    all&rdquo; if that is what you wish.  So there is no need for a
192    separate &ldquo;freedom not to run a program.&rdquo;</p>
193    
194    <h4>The freedom to study the source code and make changes</h4>
195    
196    <p>
197    In order for freedoms 1 and 3 (the freedom to make changes and the
198    freedom to publish the changed versions) to be meaningful, you need to have
199    access to the source code of the program.  Therefore, accessibility of
200    source code is a necessary condition for free software.  Obfuscated
201    &ldquo;source code&rdquo; is not real source code and does not count
202    as source code.
203    </p>
204    
205    <p>
206    Freedom 1 includes the freedom to use your changed version in place of
207    the original.  If the program is delivered in a product designed to
208    run someone else's modified versions but refuse to run yours &mdash; a
209    practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
210    or (in its practitioners' perverse terminology) as &ldquo;secure
211    boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
212    practical reality.  These binaries are not free
213    software even if the source code they are compiled from is free.
214    </p>
215    
216    <p>
217    One important way to modify a program is by merging in available free
218    subroutines and modules.  If the program's license says that you
219    cannot merge in a suitably licensed existing module &mdash; for instance, if it
220    requires you to be the copyright holder of any code you add &mdash; then the
221    license is too restrictive to qualify as free.
222    </p>
223    
224    <p>
225    Whether a change constitutes an improvement is a subjective matter.
226    If your right to modify a program is limited, in substance, to changes that
227    someone else considers an improvement, that program is not free.
228    </p>
229    
230    <p>
231    One special case of freedom 1 is to delete the program's code so it
232    returns after doing nothing, or make it invoke some other program.
233    Thus, freedom 1 includes the &ldquo;freedom to delete the program.&rdquo;
234    </p>
235    
236    <h4>The freedom to redistribute if you wish: basic requirements</h4>
237    
238    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
239    redistribute copies, either with or without modifications, either
240    gratis or charging a fee for distribution, to
241    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
242    things means (among other things) that you do not have to ask or pay
243    for permission to do so.
244    </p>
245    
246  <P>  <p>
247  You should also have the freedom to make modifications and use them  You should also have the freedom to make modifications and use them
248  privately in your own work or play, without even mentioning that they  privately in your own work or play, without even mentioning that they
249  exist.  If you do publish your changes, you should not be required to  exist.  If you do publish your changes, you should not be required to
250  notify anyone in particular, or in any particular way.  notify anyone in particular, or in any particular way.
251    </p>
252    
253  <P>  <p>
254  The freedom to use a program means the freedom for any kind of person  Freedom 3 includes the freedom to release your modified versions
255  or organization to use it on any kind of computer system, for any kind  as free software.  A free license may also permit other ways of
256  of overall job, and without being required to communicate subsequently  releasing them; in other words, it does not have to be
257  with the developer or any other specific entity.  a <a href="/copyleft/copyleft.html">copyleft</a> license.  However, a
258    license that requires modified versions to be nonfree does not qualify
259    as a free license.
260    </p>
261    
262  <P>  <p>
263  The freedom to redistribute copies must include binary or executable  The freedom to redistribute copies must include binary or executable
264  forms of the program, as well as source code, for both modified and  forms of the program, as well as source code, for both modified and
265  unmodified versions.  (Distributing programs in runnable form is  unmodified versions.  (Distributing programs in runnable form is necessary
266  necessary for conveniently installable free operating systems.)  It is  for conveniently installable free operating systems.)  It is OK if there
267  ok if there is no way to produce a binary or executable form for a  is no way to produce a binary or executable form for a certain program
268  certain program (since some languages don't support that feature), but  (since some languages don't support that feature), but you must have the
269  you must have the freedom to redistribute such forms should you find  freedom to redistribute such forms should you find or develop a way to
270  or develop a way to make them.  make them.
271    </p>
272  <P>  
273  In order for the freedoms to make changes, and to publish improved  <h4>Copyleft</h4>
 versions, to be meaningful, you must have access to the source code of  
 the program.  Therefore, accessibility of source code is a necessary  
 condition for free software.  
   
 <P>  
 In order for these freedoms to be real, they must be irrevocable as  
 long as you do nothing wrong; if the developer of the software has the  
 power to revoke the license, without your doing anything to give  
 cause, the software is not free.  
274    
275  <P>  <p>
276  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
277  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
278  freedoms.  For example, copyleft (very simply stated) is the rule that  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>
279  when redistributing the program, you cannot add restrictions to deny  (very simply stated) is the rule that when redistributing the program,
280  other people the central freedoms.  This rule does not conflict with  you cannot add restrictions to deny other people the central freedoms.
281  the central freedoms; rather it protects them.  This rule does not conflict with the central freedoms; rather it
282    protects them.
283  <P>  </p>
284  Thus, you may have paid money to get copies of free software, or you  
285  may have obtained copies at no charge.  But regardless of how you got  <p>
286  your copies, you always have the freedom to copy and change the  In the GNU project, we use copyleft to protect the four freedoms
287  software, even to <A HREF="/philosophy/selling.html">sell copies</A>.  legally for everyone.  We believe there are important reasons why
288  <P>  <a href="/philosophy/pragmatic.html">it is better to use
289    copyleft</a>.  However,
290  ``Free software'' does not mean ``non-commercial''.  A free program  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
291  must be available for commercial use, commercial development, and  noncopylefted free software</a> is ethical
292  commercial distribution.  Commercial development of free software is  too.  See <a href="/philosophy/categories.html">Categories of Free
293  no longer unusual; such free commercial software is very important.  Software</a> for a description of how &ldquo;free software,&rdquo;
294    &ldquo;copylefted software&rdquo; and other categories of software
295  <P>  relate to each other.
296  Rules about how to package a modified version are acceptable, if they  </p>
297  don't effectively block your freedom to release modified versions.  
298  Rules that ``if you make the program available in this way, you must  <h4>Rules about packaging and distribution details</h4>
299  make it available in that way also'' can be acceptable too, on the  
300  same condition.  (Note that such a rule still leaves you the choice of  <p>
301  whether to publish the program or not.)  It is also acceptable for the  Rules about how to package a modified version are acceptable,
302  license to require that, if you have distributed a modified version  if they don't substantively limit your freedom to release modified
303  and a previous developer asks for a copy of it, you must send one.  versions, or your freedom to make and use modified versions privately.
304    Thus, it is acceptable for the license to require that you change the
305  <P>  name of the modified version, remove a logo, or identify your
306  In the GNU project, we use <A HREF="/copyleft/copyleft.html">  modifications as yours.  As long as these requirements are not so
307  ``copyleft''</A> to protect these freedoms legally for everyone.  But  burdensome that they effectively hamper you from releasing your
308  <A HREF="/philosophy/categories.html#Non-CopyleftedFreeSoftware">  changes, they are acceptable; you're already making other changes to
309  non-copylefted free software</A> also exists.  We believe there are  the program, so you won't have trouble making a few more.
310  important reasons why <A HREF="/philosophy/pragmatic.html"> it is  </p>
311  better to use copyleft</A>, but if your program is non-copylefted free  
312  software, we can still use it.  <p>
313    Rules that &ldquo;if you make your version available in this way, you
314  <P>  must make it available in that way also&rdquo; can be acceptable too,
315  See <A HREF="/philosophy/categories.html">Categories of Free Software  on the same condition.  An example of such an acceptable rule is one
316         (18k characters)</A>  saying that if you have distributed a
317  for a description of how ``free software,'' ``copylefted software'' and  modified version and a previous developer asks for a copy of it, you
318  other categories of software relate to each other.  must send one.  (Note that such a rule still leaves you the choice of
319    whether to distribute your version at all.)  Rules that require release
320  <P>  of source code to the users for versions that you put into public use
321  Sometimes government <A NAME="exportcontrol">export control  are also acceptable.
322  regulations</A> and trade sanctions can constrain your freedom to  </p>
323  distribute copies of programs internationally.  Software developers do  
324  not have the power to eliminate or override these restrictions, but  <p>
325  what they can and must do is refuse to impose them as conditions of  A special issue arises when a license requires changing the name by
326  use of the program.  In this way, the restrictions will not affect  which the program will be invoked from other programs.  That
327  activities and people outside the jurisdictions of these governments.  effectively hampers you from releasing your changed version so that it
328    can replace the original when invoked by those other programs.  This
329  <P>  sort of requirement is acceptable only if there's a suitable aliasing
330  Most free software licenses are based on copyright, and there are  facility that allows you to specify the original program's name as an
331  limits on what kinds of requirements can be imposed through copyright.  alias for the modified version.</p>
332  If a copyright-based license respects freedom in the ways described  
333  above, it is unlikely to have some other sort of problem that we never  <h4>Export regulations</h4>
334  anticipated (though this does happen occasionally).  However, some  
335  free software licenses are based on contracts, and contracts can  <p>
336  impose a much larger range of possible restrictions.  That means there  Sometimes government <a id="exportcontrol">export control regulations</a>
337  are many possible ways such a license could be unacceptably  and trade sanctions can constrain your freedom to distribute copies of
338  restrictive and non-free.  programs internationally.  Software developers do not have the power to
339  <P>  eliminate or override these restrictions, but what they can and must do
340  We can't possibly list all the possible contract restrictions that  is refuse to impose them as conditions of use of the program.  In this
341  would be unacceptable.  If a contract-based license restricts the user  way, the restrictions will not affect activities and people outside the
342  in an unusual way that copyright-based licenses cannot, and which  jurisdictions of these governments.  Thus, free software licenses
343  isn't mentioned here as legitimate, we will have to think about it,  must not require obedience to any nontrivial export regulations as a
344  and we will probably decide it is non-free.  condition of exercising any of the essential freedoms.
345  <P>  </p>
346  When talking about free software, it is best to avoid using terms like  
347  ``give away'' or ``for free'', because those terms imply that the  <p>
348  issue is about price, not freedom.  Some common terms such as  Merely mentioning the existence of export regulations, without making
349  ``piracy'' embody opinions we hope you won't endorse.  See <A  them a condition of the license itself, is acceptable since it does
350  HREF="/philosophy/words-to-avoid.html">Confusing Words and Phrases  not restrict users.  If an export regulation is actually trivial for
351  that are Worth Avoiding</A> for a discussion of these terms.  free software, then requiring it as a condition is not an actual
352  We also have a list of <A HREF="/philosophy/fs-translations.html">translations  problem; however, it is a potential problem, since a later change in
353  of "free software"</A> into various languages.  export law could make the requirement nontrivial and thus render the
354    software nonfree.
355    </p>
356    
357    <h4>Legal considerations</h4>
358    
359    <p>
360    In order for these freedoms to be real, they must be permanent and
361    irrevocable as long as you do nothing wrong; if the developer of the
362    software has the power to revoke the license, or retroactively add
363    restrictions to its terms, without your doing anything wrong to give
364    cause, the software is not free.
365    </p>
366    
367    <p>
368    A free license may not require compliance with the license of a
369    nonfree program.  Thus, for instance, if a license requires you to
370    comply with the licenses of &ldquo;all the programs you use&rdquo;, in
371    the case of a user that runs nonfree programs this would require
372    compliance with the licenses of those nonfree programs; that makes the
373    license nonfree.
374    </p>
375    
376    <p>
377    It is acceptable for a free license to specify which jurisdiction's
378    law applies, or where litigation must be done, or both.
379    </p>
380    
381    <h4>Contract-based licenses</h4>
382    
383    <p>
384    Most free software licenses are based on copyright, and there are limits
385    on what kinds of requirements can be imposed through copyright.  If a
386    copyright-based license respects freedom in the ways described above, it
387    is unlikely to have some other sort of problem that we never anticipated
388    (though this does happen occasionally).  However, some free software
389    licenses are based on contracts, and contracts can impose a much larger
390    range of possible restrictions.  That means there are many possible ways
391    such a license could be unacceptably restrictive and nonfree.
392    </p>
393    
394    <p>
395    We can't possibly list all the ways that might happen.  If a
396    contract-based license restricts the user in an unusual way that
397    copyright-based licenses cannot, and which isn't mentioned here as
398    legitimate, we will have to think about it, and we will probably conclude
399    it is nonfree.
400    </p>
401    
402    <h4>Use the right words when talking about free software</h4>
403    
404    <p>
405    When talking about free software, it is best to avoid using terms
406    like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
407    the issue is about price, not freedom.  Some common terms such
408    as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
409    <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
410    are Worth Avoiding</a> for a discussion of these terms.  We also have
411    a list of proper <a href="/philosophy/fs-translations.html">translations of
412    &ldquo;free software&rdquo;</a> into various languages.
413    </p>
414    
415  <P>  <h4>How we interpret these criteria</h4>
416    
417    <p>
418  Finally, note that criteria such as those stated in this free software  Finally, note that criteria such as those stated in this free software
419  definition require careful thought for their interpretation.  To  definition require careful thought for their interpretation.  To decide
420  decide whether a specific software license qualifies as a free  whether a specific software license qualifies as a free software license,
421  software license, we judge it based on these criteria to determine  we judge it based on these criteria to determine whether it fits their
422  whether it fits their spirit as well as the precise words.  If a  spirit as well as the precise words.  If a license includes unconscionable
423  license includes unconscionable restrictions, we reject it, even if we  restrictions, we reject it, even if we did not anticipate the issue
424  did not anticipate the issue in these criteria.  Sometimes a license  in these criteria.  Sometimes a license requirement raises an issue
425  requirement raises an issue that calls for extensive thought,  that calls for extensive thought, including discussions with a lawyer,
426  including discussions with a lawyer, before we can decide if the  before we can decide if the requirement is acceptable.  When we reach
427  requirement is acceptable.  When we reach a conclusion about a new  a conclusion about a new issue, we often update these criteria to make
428  issue, we often update these criteria to make it easier to see why  it easier to see why certain licenses do or don't qualify.
429  certain licenses do or don't qualify.  </p>
430    
431  <P>  <h4>Get help with free licenses</h4>
432    
433  If you are interested in whether a specific license qualifies as a  <p>
434  free software license, see our <A  If you are interested in whether a specific license qualifies as a free
435  HREF="/licenses/license-list.html">list of licenses</A>.  If the  software license, see our <a href="/licenses/license-list.html">list
436  license you are concerned with is not listed there, you can ask us  of licenses</a>.  If the license you are concerned with is not
437  about it by sending us email at <A  listed there, you can ask us about it by sending us email at
438  HREF="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</A>.  <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
439    </p>
440  <HR>  
441    <p>
442  <H4><A HREF="/philosophy/philosophy.html">Other Texts to Read</A></H4>  If you are contemplating writing a new license, please contact the
443    Free Software Foundation first by writing to that address. The
444  <P>  proliferation of different free software licenses means increased work
445  Another group has started using the term "open source" to mean  for users in understanding the licenses; we may be able to help you
446  something close (but not identical) to "free software".  We prefer the  find an existing free software license that meets your needs.
447  term "free software" because, once you have heard it refers to freedom  </p>
448  rather than price, <A HREF="free-software-for-freedom.html">it calls  
449  to mind freedom</A>.  <p>
450    If that isn't possible, if you really need a new license, with our
451  <HR>  help you can ensure that the license really is a free software license
452  [  and avoid various practical problems.
453  <!-- Please keep this list alphabetical -->  </p>
454  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  
455  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <h3 id="beyond-software">Beyond Software</h3>
456  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  
457  | <A HREF="/philosophy/free-sw.da.html">Danish</A>  <p>
458  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
459  | <A HREF="/philosophy/free-sw.html">English</A>  for the same reasons that software must be free, and because the
460  | <A HREF="/philosophy/free-sw.fr.html">French</A>  manuals are in effect part of the software.
461  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  </p>
462  | <A HREF="/philosophy/free-sw.de.html">German</A>  
463  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <p>
464  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  The same arguments also make sense for other kinds of works of
465  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  practical use &mdash; that is to say, works that embody useful knowledge,
466  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  such as educational works and reference
467  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  works.  <a href="http://wikipedia.org">Wikipedia</a> is the best-known
468  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  example.
469  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  </p>
470  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  
471  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  <p>
472  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  Any kind of work <em>can</em> be free, and the definition of free software
473  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>        has been extended to a definition of <a href="http://freedomdefined.org/">
474  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  free cultural works</a> applicable to any kind of works.
475  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  </p>
476  <!-- Please keep this list alphabetical -->  
477  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  <h3 id="open-source">Open Source?</h3>
478  ]  
479  <P>  <p>
480  Return to <A HREF="/home.html">GNU's home page</A>.  Another group uses the term &ldquo;open source&rdquo; to mean
481  <P>  something close (but not identical) to &ldquo;free software&rdquo;.  We
482    prefer the term &ldquo;free software&rdquo; because, once you have heard that
483  Please send FSF &amp; GNU inquiries &amp; questions to  it refers to freedom rather than price, it calls to mind freedom.  The
484    word &ldquo;open&rdquo; <a href="/philosophy/open-source-misses-the-point.html">
485  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  never refers to freedom</a>.
486  There are also <A HREF="/home.html#ContactInfo">other ways to  </p>
487  contact</A> the FSF.  </div>
488  <P>  
489    <h3 id="History">History</h3>
490  Please send comments on these web pages to  
491    <p>From time to time we revise this Free Software Definition.  Here is
492  <A HREF="mailto:webmasters@gnu.org"><EM>webmasters@gnu.org</EM></A>,  the list of substantive changes, along with links to show exactly what
493  send other questions to  was changed.</p>
494  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  
495  <P>  <ul>
496  Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, Free  
497  Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.168&amp;r2=1.169">Version
498  02111,  USA  1.169</a>: Explain more clearly why the four freedoms must apply
499  <P>  to commercial activity.  Explain why the four freedoms imply the
500  Verbatim copying and distribution of this entire article is  freedom not to run the program and the freedom to delete it, so there
501  permitted in any medium, provided this notice is preserved.  is no need to state those as separate requirements.</li>
502  <P>  
503  Updated:  <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.164&amp;r2=1.165">Version
504    1.165</a>: Clarify that arbitrary annoyances in the code do not
505    negate freedom 0, and that freedoms 1 and 3 enable users to remove them.</li>
506    
507    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.152&amp;r2=1.153">Version
508    1.153</a>: Clarify that freedom to run the program means nothing stops
509    you from making it run.</li>
510    
511    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.140&amp;r2=1.141">Version
512    1.141</a>: Clarify which code needs to be free.</li>
513    
514    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.134&amp;r2=1.135">Version
515    1.135</a>: Say each time that freedom 0 is the freedom to run the program
516    as you wish.</li>
517    
518    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.133&amp;r2=1.134">Version
519    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
520    
521    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.130&amp;r2=1.131">Version
522    1.131</a>: A free license may not require compliance with a nonfree license
523    of another program.</li>
524    
525    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.128&amp;r2=1.129">Version
526    1.129</a>: State explicitly that choice of law and choice of forum
527    specifications are allowed.  (This was always our policy.)</li>
528    
529    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.121&amp;r2=1.122">Version
530    1.122</a>: An export control requirement is a real problem if the
531    requirement is nontrivial; otherwise it is only a potential problem.</li>
532    
533    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.117&amp;r2=1.118">Version
534    1.118</a>: Clarification: the issue is limits on your right to modify,
535    not on what modifications you have made.  And modifications are not limited
536    to &ldquo;improvements&rdquo;</li>
537    
538    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.110&amp;r2=1.111">Version
539    1.111</a>: Clarify 1.77 by saying that only
540    retroactive <em>restrictions</em> are unacceptable.  The copyright
541    holders can always grant additional <em>permission</em> for use of the
542    work by releasing the work in another way in parallel.</li>
543    
544    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.104&amp;r2=1.105">Version
545    1.105</a>: Reflect, in the brief statement of freedom 1, the point
546    (already stated in version 1.80) that it includes really using your modified
547    version for your computing.</li>
548    
549    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.91&amp;r2=1.92">Version
550    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
551    
552    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.89&amp;r2=1.90">Version
553    1.90</a>: Clarify that freedom 3 means the right to distribute copies
554    of your own modified or improved version, not a right to participate
555    in someone else's development project.</li>
556    
557    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.88&amp;r2=1.89">Version
558    1.89</a>: Freedom 3 includes the right to release modified versions as
559    free software.</li>
560    
561    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.79&amp;r2=1.80">Version
562    1.80</a>: Freedom 1 must be practical, not just theoretical;
563    i.e., no tivoization.</li>
564    
565    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.76&amp;r2=1.77">Version
566    1.77</a>: Clarify that all retroactive changes to the license are
567    unacceptable, even if it's not described as a complete
568    replacement.</li>
569    
570    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.73&amp;r2=1.74">Version
571    1.74</a>: Four clarifications of points not explicit enough, or stated
572    in some places but not reflected everywhere:
573    <ul>
574    <li>"Improvements" does not mean the license can
575    substantively limit what kinds of modified versions you can release.
576    Freedom 3 includes distributing modified versions, not just changes.</li>
577    <li>The right to merge in existing modules
578    refers to those that are suitably licensed.</li>
579    <li>Explicitly state the conclusion of the point about export controls.</li>
580    <li>Imposing a license change constitutes revoking the old license.</li>
581    </ul>
582    </li>
583    
584    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.56&amp;r2=1.57">Version
585    1.57</a>: Add &quot;Beyond Software&quot; section.</li>
586    
587    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.45&amp;r2=1.46">Version
588    1.46</a>: Clarify whose purpose is significant in the freedom to run
589    the program for any purpose.</li>
590    
591    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.40&amp;r2=1.41">Version
592    1.41</a>: Clarify wording about contract-based licenses.</li>
593    
594    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.39&amp;r2=1.40">Version
595    1.40</a>: Explain that a free license must allow to you use other
596    available free software to create your modifications.</li>
597    
598    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.38&amp;r2=1.39">Version
599    1.39</a>: Note that it is acceptable for a license to require you to
600    provide source for versions of the software you put into public
601    use.</li>
602    
603    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.30&amp;r2=1.31">Version
604    1.31</a>: Note that it is acceptable for a license to require you to
605    identify yourself as the author of modifications.  Other minor
606    clarifications throughout the text.</li>
607    
608    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.22&amp;r2=1.23">Version
609    1.23</a>: Address potential problems related to contract-based
610    licenses.</li>
611    
612    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.15&amp;r2=1.16">Version
613    1.16</a>: Explain why distribution of binaries is important.</li>
614    
615    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.10&amp;r2=1.11">Version
616    1.11</a>: Note that a free license may require you to send a copy of
617    versions you distribute to previous developers on request.</li>
618    
619    </ul>
620    
621    <p>There are gaps in the version numbers shown above because there are
622    other changes in this page that do not affect the definition or its
623    interpretations.  For instance, the list does not include changes in
624    asides, formatting, spelling, punctuation, or other parts of the page.
625    You can review the complete list of changes to the page through
626    the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
627    interface</a>.</p>
628    
629    <h3 style="font-size:1em">Footnote</h3>
630    <ol>
631    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
632    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
633    the freedom to run the program needed to be mentioned explicitly.
634    It was clearly more basic than the other three, so it properly should
635    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
636    </ol>
637    
638    </div><!-- for id="content", starts in the include above -->
639    <!--#include virtual="/server/footer.html" -->
640    <div id="footer">
641    <div class="unprintable">
642    
643    <p>Please send general FSF &amp; GNU inquiries to
644    <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
645    There are also <a href="/contact/">other ways to contact</a>
646    the FSF.  Broken links and other corrections or suggestions can be sent
647    to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
648    
649    <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
650            replace it with the translation of these two:
651    
652            We work hard and do our best to provide accurate, good quality
653            translations.  However, we are not exempt from imperfection.
654            Please send your comments and general suggestions in this regard
655            to <a href="mailto:web-translators@gnu.org">
656            &lt;web-translators@gnu.org&gt;</a>.</p>
657    
658            <p>For information on coordinating and submitting translations of
659            our web pages, see <a
660            href="/server/standards/README.translations.html">Translations
661            README</a>. -->
662    Please see the <a
663    href="/server/standards/README.translations.html">Translations
664    README</a> for information on coordinating and submitting translations
665    of this article.</p>
666    </div>
667    
668    <!-- Regarding copyright, in general, standalone pages (as opposed to
669         files generated as part of manuals) on the GNU web server should
670         be under CC BY-ND 4.0.  Please do NOT change or remove this
671         without talking with the webmasters or licensing team first.
672         Please make sure the copyright date is consistent with the
673         document.  For web pages, it is ok to list just the latest year the
674         document was modified, or published.
675        
676         If you wish to list earlier years, that is ok too.
677         Either "2001, 2002, 2003" or "2001-2003" are ok for specifying
678         years, as long as each year in the range is in fact a copyrightable
679         year, i.e., a year in which the document was published (including
680         being publicly visible on the web or in a revision control system).
681        
682         There is more detail about copyright years in the GNU Maintainers
683         Information document, www.gnu.org/prep/maintain. -->
684    
685    <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2019, 2021
686    Free Software Foundation, Inc.</p>
687    
688    <p>This page is licensed under a <a rel="license"
689    href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
690    Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
691    
692    <!--#include virtual="/server/bottom-notes.html" -->
693    
694    <p class="unprintable">Updated:
695  <!-- timestamp start -->  <!-- timestamp start -->
696  $Date$ $Author$  $Date$
697  <!-- timestamp end -->  <!-- timestamp end -->
698  <HR>  </p>
699  </BODY>  </div>
700  </HTML>  </div><!-- for class="inner", starts in the banner include -->
701    </body>
702    </html>
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