The PiNNwall plug-in allows for PiNN to interface with the MetalWalls code and to perform molecular dynamics simulations of electrochemical systems that involve heterogeneous electrodes, which goes beyond what the standard Siepmann-Sprik model 37 can offer. Here, heterogeneous electrodes refer to the ones that contain multiple chemical elements, atomic defects, surface corrugation or functionalization. The PiNNwall interface reads in the electrode structure and then predicts the charge response kernel as well as the base charge using PiNet2-χ and PiNet2-dipole respectively. This information is then passed to MetalWalls to compute the response charge of the electrode atoms under an external field E 0 accordingly