In an information processing device connected to an external device via a network, the external device includes an application platform of an image forming device and the information processing device includes a platform emulator that emulates the application platform. The platform emulator includes an implementing information acquiring part that receives a list of information items of interfaces implemented on the application platform in the external device from the external device and stores the list of information items in a holding part, a determining part that determines, in response to an interface calling request from an application using the platform emulator, whether an interface is implemented in the external device based on the stored list of information items, and an external calling part that transmits, when the interface is implemented, a request of execution of the interface to the external device.