Can I charge customer to use Software if I have created Software using open source Qt?
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Hi,
WARNING: I am NOT a lawyer.
Yes you can, LGPL does not impose anything with regard to selling software.
What you have to do is provide an easy to find and clear place in your application where you show to your users the list of libraries you use. Usually in the About part of your application. Qt even offers a dedicated message box for that.
Note that is nothing specific to Qt, any library that you use in your application that is under the LGPL has the same. Also, if you do any changes to Qt for one reason or another, you have to publish these changes.
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Thank you for quick response.
I will display the Qt library which I am using dynamically.
Just for clarification. I am not selling my software and codebase. I am planning to charge customer for use of features, which is provided by my software.
I hope this is also allow under open source Qt. Is that Correct?
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Thank you for quick response.
I will display the Qt library which I am using dynamically.
Just for clarification. I am not selling my software and codebase. I am planning to charge customer for use of features, which is provided by my software.
I hope this is also allow under open source Qt. Is that Correct?
As already written: It has nothing to do with Qt itself. The LGPL is not specific to Qt.
As for how you charge your software, whether it's for the core functionality or plugins, it's up to you.
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Hi,
WARNING: I am NOT a lawyer.
Yes you can, LGPL does not impose anything with regard to selling software.
What you have to do is provide an easy to find and clear place in your application where you show to your users the list of libraries you use. Usually in the About part of your application. Qt even offers a dedicated message box for that.
Note that is nothing specific to Qt, any library that you use in your application that is under the LGPL has the same. Also, if you do any changes to Qt for one reason or another, you have to publish these changes.
@SGaist said in Can I charge customer to use Software if I have created Software using open source Qt?:
Also, if you do any changes to Qt for one reason or another, you have to publish these changes.
In addition to what @SGaist said: You need to have the source code of the Qt version that you used. You can either provide a written offer valid for at least 3 months for your customer to request the Qt source code (not your own source code). Or you provide the Qt source code in the same way as your software (if your software can be downloaded, place a download link to the Qt source code in the same place). A download link to someone else hosting the same Qt source code does not count. You have to host it in the same place as your software.
Furthermore, the LGPL requires that the user is able to relink with a different Qt version. If you are using Qt's DLLs this is taken care of already as the user can just replace the DLLs.
