Consider the case below:

  1. A Wordpress plugin must be GPL since Wordpress itself is GPL
  2. There are some plugin authors selling premium WordPress plugins, and assume the authors are okay with the GPL license, and so they make money by providing support in their forum (1yr only after purchase, e.g. $100 for 1st year, you enjoy plugin download and ask question in the forum)
  3. Now, a theft purchase the plugin for $100 and want to re-sell the GPL-ed plugin in another website for just $10.

Can the original authors do something to the theft?

  • 4
    Why would a plugin have to be GPL licensed if it is being developed for a GPL product? That would mean no commercial application is ever possible Linux - also GPL does not say you cannot charge - example Red Hat Linux. And when CentOS rebrands and redistributes Red Hat Linux for free it isn't theft - it is in the spirit of FOSS.
    – Y123
    Commented Apr 10, 2015 at 17:42
  • legal advice is explicitly off-topic per help center
    – gnat
    Commented Apr 10, 2015 at 17:46
  • 4
    Required reading about the GPL before asking questions about it: GPL FAQ. Hint: your question is in that document.
    – user22815
    Commented Apr 10, 2015 at 17:50
  • @YazadKhambata: the GPL FAQ states clearly that some kind of plugins have to be seen as "derived works" (thus must be GPL itself), others not, and having a short look into the WordPress API makes clear that WordPress plugins fall into the first category, whilst your example (commercial application on Linux) does not even fall under the "plugin" category.
    – Doc Brown
    Commented Apr 10, 2015 at 19:18

1 Answer 1


What you describe appears to be perfectly legal.

The GPL allows any licensee (anyone who bought it) to sub-license it to others for any price they want or even for free when they feel generous. Those other people are now also licensees who can also sell or gift the software to others. So when someone offers a GPL software for $100, and you want to pay less, you can seek out any of the people who already bought it and ask them if you can buy it from them for less. This is perfectly legal and intended. The only downside is that you won't get the support service offered by the original creator, because that's a completely independent contract not covered by the GPL. But when you need help with the software, you can make a support contract with anyone else you consider qualified.

However, that only applies to people who actually did receive the program under the conditions of the GPL, either directly or through any number of sub-sub-sub-licensees. Should one steal a copy of a GPL program illegally (through hacking, for example), they are not licensees, which means they do not have the right to sub-license it, and are violating the copyright of the original author when they do.

<advertising>When you have more questions about how one can monetize GPL software, you might want to commit to the new proposal Open Source Stackexchange. It still needs people to commit to it so it can go into beta phase.</advertising>

  • Some clarification: You can charge as much as you like for the actual software. You can charge your actual cost for providing source code. You may not charge for the license. (So I could charge you $100 for a CD with an app, maybe $10 for a CD with the source code, but nothing at all for the GPL license).
    – gnasher729
    Commented Apr 10, 2015 at 22:13
  • @gnasher729 I would like to know how this makes a difference in practice, but I think this goes too deep for programmers.se. I think I will ask a question about this on open source stackexchange when it goes into beta. Maybe you would like to commit to it so you can answer it then?
    – Philipp
    Commented Apr 11, 2015 at 9:17
  • I might have dual licensed software, and be the copyright owner. I sell it to you for $100 without GPL. I'm not allowed to charge you $200 with GPL license. I'm allowed to charge $200 with or without GPL, but I may not charge more for the GPL license. A concrete example is Apple's App Store, which explictely says that payments are for the license - which means you cannot ask for cash for GPL'd code; it must be free of charge to follow both GPL rules and app store rules.
    – gnasher729
    Commented Apr 11, 2015 at 11:53
  • @gnasher729 I don't think that this is correct. When you are the sole copyright holder you should be allowed sell it for any price to any conditions you want. When you are not you only have the GPL which doesn't give you another choice than licensing it under GPL. I think we should explore this in form of a proper question when Open Source Stackexchange goes into beta.
    – Philipp
    Commented Apr 12, 2015 at 18:37
  • The rules for payment are so that you cannot claim that something is GPL licensed while making it impossible for people to get their rights. So you can charge reasonable costs for providing a copy of the source code, but you cannot charge a million dollars which would make it practically impossible for me to get the source code which I should be able to get.
    – gnasher729
    Commented Aug 17, 2015 at 18:29

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