The scientific goals of the PLATO mission are to search for planetary transits across a large number of stars. We describe its end-to-end data processing architecture, including the infrastructure to configure the instrument consisting of 26 cameras and 14 data-processing units, the on-board data acquisition, processing and storage, and the ground processing pipeline. In the case of PLATO, only the combination of onboard and on-ground data processing makes it possible to achieve the ambitious goals.