Accurate stellar parameters, Teff and chemical composition, are imperative for the determination of masses, radii, and ages of PLATO stars. I will present the architecture and input physics of the SAPP pipeline that will be used to determine non-seismic stellar parameters for the PLATO core sample. In this talk, I will discuss how we cope with rapid yet painstaking developments in stellar atmosphere modelling, including radiation hydrodynamics theory, atomic and molecular physics, machine learning and numerical analysis methods, - the developments that form the basis of the unique diagnostic capabilties of the SAPP. I will highlight our successes and challenges, and close with the prospects for PLATO and other future projects that aim to capitalise on unprecendeted data available from ground- and space-based observations.