[Display omitted] • Increasing importance of hydrogen in the current and future energy scenario. • A fully-customisable simulation platform for PEM electrolyzer models is designed. • Control, simulation, visualisation and comparison of models are archived. • Graphical User Interface to facilitate interactivity between the user and the models. • Interaction of three environments: MATLAB, Simulink and App Designer. This work presents the development and implementation of a simulation platform based on MATLAB/Simulink devoted to analysing the behaviour of Polymer Electrolyte Membrane (PEM) electrolyzer (PEMEL) models. A graphical user interface (GUI) designed in App Designer is included for controlling the platform and visualising simulation results. Through this GUI, the user is able to study the models hosted on the platform under various operating conditions, compare the results obtained and even modify the characteristic parameters of the models. The main objective of the platform is to facilitate the study of PEMEL for the development of a digital replica of a physical device housed in a smart microgrid. In these systems, PEMEL are integrated with renewable energy sources for the generation of green hydrogen, which is used as an energy carrier to cope with variations in demand in the medium and long term. The proposal overcomes the limitations identified in previous literature such as the absence of a GUI to facilitate model handling, model modification and the comparison and simulation of different models in the same application. The design and implementation of the simulation platform is reported along with a series of simulation cases to prove its feasibility and successful performance. [ABSTRACT FROM AUTHOR]