Python-C Parallel KVFinder (pyKVFinder) is an efficient and integrable Python package for biomolecular cavity detection and characterization in data science. Besides conventional cavity properties such as volume and area, which are stored as Python dictionaries, pyKVFinder computes cavity depth and hydropathy. Similar to cavity points, these spatial and physicochemical properties are stored as Python ndarrays and can be visualized using Python molecular visualization widgets. In general, pyKVFinder is designed for efficient scripting routines built on easy-to-handle data structures, such as Python dictionaries and NumPy N-dimensional arrays (ndarrays), and can be building blocks for data science and drug design applications.