PyQt is a set of Python bindings for The Qt Company's Qt application framework. The bindings are implemented as a set of Python modules and contain over 1,000 classes.
PyQt6 supports Qt6 and runs on Windows (Intel and ARM), macOS (Intel and Apple Silicon) and Linux (Intel and ARM).
PyQt5 supports Qt5 and runs on Windows (Intel), macOS (Intel and Apple Silicon), Android, iOS and Linux (Intel).
PyQt4 supports Qt v4 but both are no longer supported and no new releases will be made.
PyQt is dual licensed on all supported platforms under the GNU GPL v3 and the Riverbank Commercial License. Unlike Qt, PyQt is not available under the LGPL. You can purchase the commercial version of PyQt here. More information about licensing can be found in the License FAQ.
PyQt does not include a copy of Qt. You must obtain a correctly licensed copy of Qt yourself. However, binary wheels of the GPL version of PyQt6 and PyQt5 are provided and these include a copy of the corresponding LGPL version of Qt.
A description of the components of PyQt5 can be found in the PyQt5 Reference Guide.
A description of the components of PyQt4 can be found in the PyQt4 Reference Guide.
PyQt brings together the Qt C++ cross-platform application framework and the cross-platform interpreted language Python.
Qt is more than a GUI toolkit. It includes abstractions of network sockets, threads, Unicode, regular expressions, SQL databases, SVG, OpenGL, XML, a fully functional web browser, a help system, a multimedia framework, as well as a rich collection of GUI widgets.
Qt classes employ a signal/slot mechanism for communicating between objects that is type safe but loosely coupled making it easy to create re-usable software components.
Qt also includes Qt Designer, a graphical user interface designer. PyQt is able to generate Python code from Qt Designer. It is also possible to add new GUI controls written in Python to Qt Designer.
Python is a simple but powerful object-orientated language. Its simplicity makes it easy to learn, but its power means that large and complex applications can be created. Its interpreted nature means that Python programmers are very productive because there is no edit/compile/link/run development cycle.
Much of Python's power comes from its comprehensive set of extension modules providing a wide variety of functions including HTTP servers, XML parsers, database access, data compression tools and, of course, graphical user interfaces. Extension modules are usually implemented in either Python, C or C++. Using tools such as SIP it is relatively straight forward to create an extension module that encapsulates an existing C or C++ library. Used in this way, Python can then become the glue to create new applications from established libraries.
PyQt combines all the advantages of Qt and Python. A programmer has all the power of Qt, but is able to exploit it with the simplicity of Python.