Due to their chemical plasticity, Cysteine residues (Cys) can serve many different functions. Identification and classification of reactive Cys isnt a trivial job: currently, no available tool exists for an all-round, comprehensive (inclusive of all different functional types) analysis of Cys, herein we present a computational platform called Cp i pe, dedicated to this task: it implements state-of-the art protocols, elaborating and displaying a wealth of information, sufficiently orthogonal to allow a thorough evaluation of all major aspects of Cys reactivity.