Licensing¶

KFR is dual licensed. You may use it under the GNU General Public License, version 2 or later (GPLv2+), or under a commercial KFR license. You must comply with one of these licenses before distributing software that uses KFR.

Using KFR under GPLv2+¶

GPLv2+ is designed for software whose source code is available to its users. It allows you to use, study, modify, and redistribute KFR, including in commercial products.

When you distribute an application that uses KFR under GPLv2+, you must also publish the complete corresponding source code under GPLv2+ and preserve the applicable copyright and license notices. For KFR, this includes your application and all libraries linked with it, whether the linkage is static or dynamic. Recipients must be able to obtain, modify, and redistribute that source code under the GPL.

In practical terms, GPLv2+ is suitable when you can release the complete source code for the distributed product and its linked libraries under the GPL. It is not suitable for distributing a closed-source application that links to KFR.

Commercial license¶

If you cannot comply with the GPLv2+ requirements and still want to use KFR, you must purchase a commercial license. A commercial license lets you use KFR in proprietary or closed-source software without the GPL publication requirements.

Purchase a commercial license at kfr.dev/purchase. Commercial licenses are perpetual, and future KFR versions are always available free of charge to licensed users.

Important¶

This page is a short, practical overview and is not legal advice. Read the full GPLv2 license and consult a qualified legal professional if you need advice about your specific use case.