h5py is a Python library that provides an interface to the HDF5 (Hierarchical Data Format version 5) binary data format. It allows users to store and manipulate large amounts of numerical data efficiently. With h5py, you can create, open, and modify HDF5 files, which are designed to handle large datasets flexibly and with high performance. The library integrates closely with NumPy, offering robust support for NumPy arrays and enabling seamless data exchange between HDF5 files and Python data structures. This makes it particularly useful for scientific computing, data analysis, and machine learning applications.