.. _ref-deploy-commercial: Deploying Commercial PyQt4 Applications ======================================= When deploying commercial PyQt4 applications it is necessary to discourage users from accessing the underlying PyQt4 modules for themselves. A user that used the modules shipped with your application to develop new applications would themselves be considered a developer and would need their own commercial PyQt4 license. One solution to this problem is the `VendorID <http://www.riverbankcomputing.com/software/vendorid/>`__ package. This allows you to build Python extension modules that can only be imported by a digitally signed custom interpreter. The package enables you to create such an interpreter with your application embedded within it. The result is an interpreter that can only run your application, and PyQt4 modules that can only be imported by that interpreter. You can use the package to similarly restrict access to any extension module. In order to build PyQt4 with support for the VendorID package, pass the :option:`--vendorid <configure.py --vendorid>` command line option to :program:`configure.py`.
