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Licensing question for my project



  • Hey, guys! How are you doing?

    So, I created an open source project based on Qt fifteen years ago and I'm running it until today. Since the project is mature enough, I would like to create a second version of the project with some extra features but only for a paying audience in order to gather some financial support. :)

    I'll keep working on the "standard" version applying patches and creating small new features here and there, and, of course, distributing its source code under GPL3. The "paid" version will receive more focus on new major features, while its source will be available only to the paying users, on demand.

    My question is: can I work on this monetization model without breaking Qt's open source license? Sometimes I get confused by the license options, so I would like to get some advices from people more used to them. :)

    I think that the commercial version of Qt can attend me on this matter but the prices, unfortunately, can't fit my pocket! Even the "small business" license is to expensive for me. :(

    Thanks in advance!


  • Moderators

    @rkhaotix said in Licensing question for my project:

    So, I created an open source project based on Qt fifteen years ago and I'm running it until today.

    Congrats! It's good to see longevity in a project :-D

    My question is: can I work on this monetization model without breaking Qt's open source license?

    The main question is: Which Qt license are you using?

    • If you use Qt under the GPL, then your software must also be released under the GPL. You can ask for payment, but all the usual GPL rules apply (e.g. you must share the source code with your customers, allow them to modify and rebuild the code, and allow them to share the code with others)
    • If you use Qt under the LGPL, then you can release your software under a different license.

    Note: All Qt modules are available under the GPL and commercial licenses, but only a subset are available under the LGPL.



  • Hi @JKSH

    Currently, I'm using Qt under GPL. Anyway, your explanation was quite clarifying. It's not my intention to close the source completely, I just want to make the improved version available for the paying users, so I think I can keep sticking with GPL.

    Thanks for your response.


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