Spatialize is an open-source Python/C++ library for Ensemble Spatial Interpolation (ESI), combining simple interpolation with geostatistics like Kriging. It uses random space partitions (Mondrian and Voronoi forests) and ensemble learning for robust, scalable spatial interpolation and uncertainty quantification. Designed for non-experts, Spatialize supports gridded and non-gridded data, automates hyperparameter search, and delivers competitive accuracy in geoscientific applications.