Many of the modern programming languages are backed up by a set of libraries (commonly referred to as toolkits) to create GUI applications, such as Qt, Tcl/Tk, and so on. PySide is a Python binding of the cross-platform GUI toolkit Qt, and it runs on all platforms that are supported by Qt, including Windows, Mac OS X, and Linux. It is one of the alternatives to toolkits such as Tkinter for GUI programming in Python.

PySide combines the advantages of Qt and Python. A PySide programmer has all the power of Qt, but it is able to exploit it with the simplicity of Python. PySide is licensed under the LGPL version 2.1 license, allowing both Free/Open Source software and proprietary software development. PySide is evolving continuously, like any other open source product, and you are free to contribute to its development. Some of the applications, such as matplotlib, PhotoGrabber, QBitTorrent, Lucas Chess, Fminer and so on, certify the wide spread usage of PySide in the software industry.

PySide has also become an enabler of mobile development. Qt Mobility is a project that is creating a new suite of Qt APIs for mobile device functionality. The project Pyside Mobility is a set of bindings that allows Python to access the Qt Mobility API. The Qt Mobility API enables the developer to access the bread and butter of services provided by the underlying operating system that are essential for any mobile application. Learning PySide, you learn this for free. Without further ado, let's get hacking!