The present disclosure provides systems and methods for processing ammonia. A heater may heat reformers, where the reformers comprise ammonia (NH3) reforming catalysts in thermal communication with the heater. NH3 may be directed to the reformers from storage tanks, and the NH3 may be decomposed to generate a reformate stream comprising hydrogen (H2) and nitrogen (N2). At least part of the reformate stream can be used to heat reformers. Additionally, the reformate stream can be directed to a hydrogen processing module such as a fuel cell.