Chromo (formerly known as IMPY) is a Python frontend that provides a unified interface to popular generators of hadronic interactions, such as EPOS, DPMJet, QGSJet, Sibyll, and Pythia, which are used to simulate air showers or minimum bias events at colliders. Chromo is a thin wrapper on top of these codes, which are written in Fortran or C++, and does not impose a notable performance penalty. As a Python library, Chromo runs in Jupyter notebooks or Python scripts and also comes with a command-line mode similar to the program CRMC. Events can be written to HepMC and ROOT files or exposed as Numpy arrays. These can be inspected and transformed with Python code, directly accumulated as histograms, and saved to disk even after modifications. Chromo’s source code is distributed via GitHub and is automatically tested and built by a continuous integration service. The installation process is extremely simple, since the software package is distributed as a binary wheel via PyPI for Linux, macOS, and Windows. Therefore, it can be readily used in education, for new projects, or as a drop-in replacement for CRMC. Chromo is the central tool for the computing of secondary particle distributions in the MCEq cascade solver, and has been extensively used for the development and testing of the DPMJet and Sibyll event generators.