MolScore is an open-source software written in Python 3, published under an MIT license and distributed via GitHub (). It depends on several packages such as RDKit [20], PyTorch , Streamlit, as well as integrating published works in the field such as RAscore , AiZynthFinder and ChemProp . MolScore is split into two sub-packages: 1) molscore for scoring de novo molecules proposed by a generative model, and 2) moleval for post-hoc evaluation using a suite of evaluation metrics. The structure of the sub-packages can be seen in Figure and integration into goal-directed de novo molecule generation in Figure . The following sections provide details of each subpackage.