BindProfX is a renewed approach to assess protein-protein binding free-energy changes (ΔΔG) induced by single- and multiple-mutations. This is an update on the BindProf method, which was designed to calculate the protein binding free-energy from the multiple sequence alignments of interface structure profiles. The major difference between BindProf and BindProfX is at the core algorithm to assess binding free-energy: While BindProf is based on the log-odds likelihood calculation, BindProfX calculates the binding free-energy change as the logarithm of relative probability of mutant amino acids over wild-type ones, which significantly increased the correlation to the experimental ΔΔG measurements. The improvement is mainly due to the introduction of multiple pseudo counts that account for the inter-amino acid mutation probability and improve the robustness of the profile score on limited structural library. BindProfX is particularly useful for designing and engineering protein-protein interactions with enhanced binding affinity. It has also the power to help understand roles of disease-related mutations associated with protein-protein interactions (>> Read more about BindProfX).