- Info
Open Source Business Model
Qt products are available under a software licensing model called Dual Licensing. Under the Dual Licensing model, Qt products are available under both a commercial license for proprietary software development, and under the GPL (General Public License; Versions 2 and 3) for development of free and open source software.
LGPL to be Added to Qt Licensing Model with Qt 4.5
On January 14th, Nokia announced that its Qt cross-platform user interface (UI) and application
framework for desktop and embedded platforms will be available under the open
source LGPL version 2.1 license from the release of Qt 4.5, scheduled for March
2009. For more information, review
the announcement.
Dual Licensing: Quid pro quo
The Dual Licensing model is based on the principal of Quid pro quo: literally meaning “something for something.” Simply put, this is how it works: In return for the value you receive from using Qt to create your application, we require that you give back by doing one of the following – depending on the type of software you yourself are developing:
| Developing commercial software? |
Developing open source software? |
| Contribute to the continued development of Qt by purchasing a commercial license from Qt Software. This option secures you the right to develop, use and distribute your application under the standard commercial license terms of your choice. |
Contribute to free and open source software development by placing your application under an Open Source license (e.g. GPL version 2 or GPL version 3). This GPL demands that all users the rights to obtain, modify and redistribute the full source code of your application. |
Please note that it is necessary to choose either the Open Source or Commercial license at the outset of your development project. Qt’s commercial license terms do not allow you to start developing proprietary software using the Open Source licensing.
Dual Licensing a Key to Our Success
By offering Qt both commercial and open source licenses since 1994, Qt Software (originally Trolltech) has been able to grow steadily and rapidly deliver new innovation in Qt. Learn more about our cooperation with the open source community.
More information on Qt licensing options can be found at the Qt Licensing page.
Partnership with the Open Source Community
In addition to commercial licenses, since 1996 Qt has been available for open source development under the GPL (General Public License). This has resulted in the emergence of a large and dynamic community of software developers who use Qt to develop exciting free and open source software projects – such as the KDE Linux Desktop Environment, Scribus, Licq and Last.fm.
The Virtuous Cycle
This active community of both commercial and open source developers is the key reason why Qt has become the standard cross-platform application framework. The symbiotic relationship we enjoy with our user communities is best illustrated through what we call The Virtuous Cycle:
Through the sale of Qt to commercial customers, we are able to staff a full-time development team dedicated to building and releasing new versions of Qt, and can provide our customers with first-class technical support and services.
By freely providing Qt under open source licenses, we receive a broad stream of incoming input from a community of thousands of open source software developers who use Qt every day. This allows us to build more innovation into Qt, and release stable new Qt versions back to our community of users more quickly, speeding the cycle of innovation.
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