Host-guest complexes can also avoid ambiguities that arise in protein-ligand systems, such as uncertain protonation states. Thus, experimental host-guest binding data are an appealing additional data type to integrate into the experimental dataset used to optimize potential functions. Here, we report the extension of the Open Force Field Evaluator framework to enable the systematic calculation of host-guest binding free energies and their gradients with respect to force field parameters, coupled with the curation of 126 host-guest complexes with available experimental binding free energies.