A computer device is provided that includes a processor and non-volatile memory including stored instructions executable by the processor, the stored instructions being configured to cause the processor to execute an operating system including an application programming interface for an on-demand installer that is callable by installed application programs during run-time. The on-demand installer is configured to receive a request from an application program to install a target resource package of the application program, query an installer server that is a source of an application program package of the application program to retrieve the target resource package from the installer server, and install the target resource package of the application program.