[PyQt] PyQt Licensing Issue

Richard Esplin richard-lists at esplins.org
Wed Dec 9 15:32:04 GMT 2009

Your confusion is understandable, especially with the recent Qt licensing changes made by Nokia.

However, the licensing changes make it much less expensive to use PyQt to produce proprietary applications.

The key thing to understand is that you need a separate license for each tool in your development stack. The Qt and PyQt licenses are different.

Qt is released under the LGPL. You therefore only need to release your changes to the Qt source code itself. If you want to keep those changes proprietary, you need a commercial license.

PyQt is released under the GPL. You therefore need to release all code you build using PyQt unless you purchase a commercial license.

I previously had to avoid PyQt on client projects because of the costs of the PyQt + Qt development stack. However, I think the cost of PyQt alone is pretty reasonable.

I'm redirecting this email back to the list so that someone will hopefully correct any errors I make in this explanation.

Good luck,


On Wed 9 December 2009 05:58:47 Prashant Saxena <animator333 at yahoo.com> wrote:
> Buying a commercial PyQt license is not a problem. But if in any case I would be needing files(.dll or .lib) from Qt SDK then I am sure
> I have to buy Qt's commercial license also and that would be too costly.
> Right now I haven't done any test but I'll compile some application modules(.py) using (gcc+cython) for code protection
> as well as speed gains. I don't if in this case PyQt's (.dll or .lib) files would do the job or I would be needing Qt's files also.
> I do have a bit of confusion here.
> Prashant
> ----- Original Message ----
> From: Richard Esplin <richard-lists at esplins.org>
> To: pyqt at riverbankcomputing.com
> Sent: Wed, 9 December, 2009 12:55:01 PM
> Subject: Re: [PyQt] PyQt Licensing Issue
> If you don't want to give away your code, you should buy the commercial license.
> Richard
> On Wed 9 December 2009 00:12:45 james infield <bimbam09 at gmail.com> wrote:
> > Hello,
> > 
> > That might be slightly off topic what do you mean by "...I won't be
> > including the source code..." ?
> > 
> > Is that your code or PyQt code ?
> > Is there a way to release without giving your code and/or PyQt code ?
> > 
> > bimbam

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