Qt is a powerful cross-platform application library which is ideal for connected devices. In Sailfish OS systems it serves as the main application development environment and provides consistent APIs into most other commonly used device functions. Sailfish currently uses Qt version 5.2, but is working on updating the stack to Qt 5.6.
The following modules are used within Sailfish OS:
There are many other Qt modules which are not used; most are obvious but these are worth noting: