pyGIMLi is a mature open-source geophysical modelling and inversion library, implemented as a C++ core with Python bindings. It provides mesh generation, finite-element solvers, data containers, and high-level manager classes for methods such as electrical resistivity tomography (ERT), vertical electrical sounding (VES), frequency-domain electromagnetics (FDEM), magnetics, gravity, traveltime, and spectral induced polarization. The library is not a GUI application; it is a programmatic toolkit with Python entry points, example scripts, and a console-app pattern in some managers.