Cross-platform JSON-driven MSI package builder. Unlike a bunch of WiX/wixl wrappers (python-wix, go-msi, msi-packager etc.) WiX.Py is a standalone application. It uses libmsi on UNIX platforms and msi.dll on MS Windows. Application has been designed for build toolchains under Docker environment, i.e. it doesn't depend on windowing system or networking features. Thus it allows building MSI packages in CI services without dedicated MSW cloud instance. This one decreases project infrastructure cost and speed-ups builds.