Geochemical modeling plays a crucial role in understanding natural processes in soils and other porous media. However, the implementation of reactive transport models in multiphysics platforms often encounters difficulties, especially when the use of extensive geochemical databases is needed, as it requires the manual creation of libraries containing the necessary formulation of each chemical species. The present work addresses this limitation by means of a tool created in Python capable of efficiently managing large geochemical databases in Phreeqc format. DAT4GM software (DAT file for Geochemical Modeling) allows the generation of the necessary code to model reactive transport in multiphysics platforms automatically, regardless of the number of species composing the selected geochemical system. Additionally, it can define the initial and boundary conditions of the transport problem. For the verification of this tool, different cases have been implemented in COMSOL. These include geochemical speciation and reactive transport with redox species in a one-dimensional configuration. In all cases, the results are satisfactory, even with geochemical configurations involving a large number of components and secondary species.