When do I need a license to use Qt’s framework, tools, or libraries?

To protect the interest of the creators and maintainers of Qt, every user of Qt must either have a valid commercial license or needs to agree to the open-source terms and conditions. The commercial Qt license gives you the full rights to create and distribute software on your own terms without any open source license obligations. The Qt open-source licensing is ideal for use cases such as open source projects with open-source distribution, student/academic purposes, hobby projects, internal research projects without external distribution, or other projects where all GPL and LGPL obligations can be met.