This paper presents a software platform based on open source tools to simulate and fit parameter values of sensor device models based on MOSFET like the ISFET. In electronic simulation, electrical and mathematical models allow to describe the behavior of electronic devices. Although manufacturers provide device models, in some cases, this information is not enough to simulate their characteristics. In order to improve the parameter values of mathematical model, the fitting procedure compares the measured and simulated data. This platform allows testing different models such as ISFET or MOSFET using freely available SPICE simulator engines. It constructs the netlist based on the classical ISFET behavioral macromodel considering the values entered by the user, then via a set of methods simulate this customized model for both characteristics curves iDS vs vGS and iDS vs vDS and compare them with experimental results obtained from a characterization process.