I found an interesting project (tool for numerical simulations) on Github with the following paragraph in its README:

You can redistribute it and/or modify it under the terms of the GNU General Public License version 3 as published by the Free Software Foundation. For the terms of this license, see licenses/gpl_v3.txt or http://www.gnu.org/licenses/ .

For a commercial usage/redistribution, please contact XXX to obtain a commercial license.

Does this make sense? To my understanding software under GPLv3 can be used commercially (e.g. as tool for company-internal calculations) with no restriction. Or am I wrong?

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    There's a large but when using GPLv3 software commercially: You cannot redistribute it with a larger closed-source project. So you cannot sell a commercial software that uses GPLv3 libraries. That's what LGPL is for.
    – PMF
    Oct 11, 2021 at 12:15
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    @PMF: You also cannot put it on locked hardware, which a lot of manufacturers want to do these days.
    – Kevin
    Oct 11, 2021 at 20:59
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    But you can "use" it yourself for commercial purposes. Just not bundle it in with any offering that leaves your hands. This does not exclude making it a prerequisite for your product as long as your product as shipped is not tainted with it.
    – mckenzm
    Oct 12, 2021 at 1:25
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    @PMF You definitely CAN sell commercial software that uses GPLv3, it just cannot be closed source. See Red Hat Enterprise Linux as an example of commercial software that contains a lot of GPLv3 components.
    – slebetman
    Oct 12, 2021 at 2:34
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    @PMF I've been involved with several projects where people definitely sold GPL software. The GPL license only governs the distributor of the software and the user. As long as both parties don't give away the source code you're still complying with GPL. GPL only requires the distributor to provide source to the user - not other 3rd parties. In one case the vendor does not want the source to be available to 3rd parties and the user is a government agency who also does not want the source to be available to 3rd parties. So GPLv3 is satisfied but the software is still not available to the public.
    – slebetman
    Oct 12, 2021 at 6:34

3 Answers 3


The second paragraph is an invitation for people who don't want to follow the terms of the GPL (e.g. who want to incorporate it into a larger closed-source work, or make closed-source modifications) to contact XXX for a less onerous (but more expensive) license. That would require that XXX have full rights to the software, that they did not for instance incorporate others' GPLed code.

It would be a stretch to read the second paragraph as attempting to limit the first paragraph, particularly given the "please".

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    Yep, the "please contact" for a different licence reads like an invitation to treat
    – user35069
    Oct 11, 2021 at 11:17
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    I doubt the "please" makes a difference Oct 12, 2021 at 8:17
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    @user253751 You'd be wrong to doubt it. In Landmark American Insurance Co. V. Lonergan Law Firm, PLLC, the court found that a contractual clause containing the world "please" was to be interpreted as a request, not a term of the contract.
    – Sneftel
    Oct 12, 2021 at 9:04
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    @Sneftel But note that the quoted text is not from the contract. It's just a descriptive text which essentially says "Click here to see the terms of the licence, or contact us if you want a different licence".
    – JBentley
    Oct 12, 2021 at 11:50
  • @JBentley You don't feel that "You can do X (which you would not otherwise have permission to do) as long as you do Y" constitutes a unilateral contract?
    – Sneftel
    Oct 12, 2021 at 12:08

To my understanding software under GPLv3 can be used commercially (e.g. as tool for company-internal calculations) with no restriction.

No, it can't be used commercially with no restriction. It must comply with the restrictions of the GPLv3, therefore it can only be used commercially within the restrictions of the GPLv3 (just like for non-commercial use).

Some companies don't like to comply with the terms of the GPLv3, e.g. they don't want to release their source code.

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    No, and this is a common misunderstanding of the GPL. It is addressed in the GPL FAQ (gnu.org/licenses/gpl-faq.en.html), which states "an organization can make a modified version and use it internally without ever releasing it outside the organization."
    – throx
    Oct 12, 2021 at 6:10
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    Can you clarify? In my answer, I say that you cannot use it commercially with no restriction, you have to comply with the restrictions in the GPLv3. In your comment, you say you can use it commercially if you comply with the restrictions of the GPLv3. So, as far as I can see, we are in perfect agreement, yet, you start your comment with "No, and this is a common misunderstanding of the GPL". What do you mean by that? Are you saying that the restriction not to publish the software is not a restriction? Oct 12, 2021 at 6:30
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    It's the perennial glass-half-whatever argument over whether GPL'd software restricts its recipients' freedom or grants them more freedom than they would otherwise have. This discussion is known to not be fruitful.
    – Sneftel
    Oct 12, 2021 at 9:08
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    @JanDorniak And JörgWMittag's point is that "for certain use cases GPL is not restrictive for commercial usage" (which implies that for certain other use cases GPL is restrictive) is just another way of rephrasing "it can only be used commercially within the restrictions of the GPL".
    – JBentley
    Oct 12, 2021 at 11:54
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    There are no restrictions in the GPLv3 on commercial usage, and impliying otherwise is at best misleading. Oct 13, 2021 at 22:07

On Open Source Initiative website you can get an explicite answer to your question. This website have list of all opensource licences including GNU GPLv3 :

Can Open Source software be used for commercial purposes?
Absolutely. All Open Source software can be used for commercial purpose; the Open Source Definition guarantees this. You can even sell Open Source software.

However, note that commercial is not the same as proprietary. If you receive software under an Open Source license, you can always use that software for commercial purposes, but that doesn't always mean you can place further restrictions on people who receive the software from you. In particular, copyleft-style Open Source licenses require that, in at least some cases, when you distribute the software, you must do so under the same license you received it under.

So for part, To my understanding software under GPLv3 can be used commercially (e.g. as tool for company-internal calculations) with no restriction.

You are correct software under GPLv3 can be used commercially with no restriction. But in that case your developed code must also be under GPLv3 and this is the restriction imposed so that no middlemen could strip off the freedom.

Intention is clear in What Is Copyleft? section.

The simplest way to make a program free is to put it in the public domain, uncopyrighted. This allows people to share the program and their improvements, if they are so minded. But it also allows uncooperative people to convert the program into proprietary software. They can make changes, many or few, and distribute the result as a proprietary product. People who receive the program in that modified form do not have the freedom that the original author gave them; the middleman has stripped it away.

In the GNU project, our aim is to give all users the freedom to redistribute and change GNU software. If middlemen could strip off the freedom, we might have many users, but those users would not have freedom. So instead of putting GNU software in the public domain, we “copyleft” it. Copyleft says that anyone who redistributes the software, with or without changes, must pass along the freedom to further copy and change it. Copyleft guarantees that every user has freedom.


To copyleft a program, we first state that it is copyrighted; then we add distribution terms, which are a legal instrument that gives everyone the rights to use, modify, and redistribute the program's code or any program derived from it but only if the distribution terms are unchanged. Thus, the code and the freedoms become legally inseparable.

That mean, if you are using GPLv3 licenced software then your developed application is also abide by GPLv3 and you need to share your source code with your client i.e. by putting it in public domain, share a copy of code with software etc.

Here comes the For a commercial usage/redistribution, please contact XXX to obtain a commercial license. part of the README. Offten, venders choose not to share their source code but wants to use the softwares which are available under GPLv3 licences. In that case, vendors evaluate the software and if it fits to their need then they ask for non-GPL licence from the origional software provider if the software provider have this option ( which is in this case).

  • No, your software is not in the public domain. If it was in the public domain, you'd have no obligations. You have the choice to always, without exception, distribute your software with source code, and then you have no further obligation to anyone. (Although those receiving the software could distribute it further, as long as they follow their obligations).
    – gnasher729
    Oct 16, 2021 at 11:12
  • @gnasher729 Yes, The requirement is that The source code must be availed to client. But not necessory to share with others ( and so not necessory to put in public domain). Putting the source code in public domain is just an example that how sourte code can be shared. Updated.
    – cse
    Oct 16, 2021 at 11:39

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