ProCaliper is an open-source Python library for functional and structural analysis, visualization, and annotation of proteomic data. ProCaliper enables interfacing with annotation resources such as UniProt, PhosphoSitePlus, AlphaFold, or user-supplied experimental data for computing structural and electromchemical property information, construction and analysis of residue-residue distance networks, and functional site identification at the residue or protein level. Funding Acknowledgments The software described here was funded by the Predictive Phenomics Science & Technology Initiative, conducted under the Laboratory Directed Research and Development Program, at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy Office of Science under Contract No. DE-AC05-76RL01830.