Utilizing the user-supplied coordinates of a protein structure, the COREX/BEST Server generates a structural thermodynamic ensemble. This conformational ensemble can then be used to calculate the regional variations in stability of a protein structure, and the stabilities are presented in units of energy (kcal/mol). The regional stabilities, which are calculated at the resolution of individual residues, can be mapped onto the protein structure for visual representation and downloaded from the site in the form of tab delimited text. The site provides an easy to follow summary of the theoretical and algorithmic approaches and provides links to references for more detailed descriptions.