The idea of the SYBA score is to train a model on comprehensive representations of both existing, easyto-synthesize compounds as well as non-existing, hardto-synthesize compounds. The former set was randomized from the ZINC15 database and the latter set was created from an easy-to-synthesize one using Nonpher tool by the iterative perturbing structure of the input molecules (adding/removing of atom or bond) up to a predefined complexity threshold. SYBA is a Bernoulli naïve Bayes classifier trained on both sets and it is available as a Conda package or at .