Wim for two inverters

Hi Renzo, I appreciate very much your work!! Very impressive to me. I thank you for this efforts! My SolarLog has gone after a lightining so I built your logger and it works well (sometimes recordings on SD cards is blocking, I investigate...). I have two inverters so I'm going to modify your firmware to gather data from inverters one and two. I developed a small React application (now only on PC, I'm new on this enviroment) to show the data-graph. My question is: how is possible to address the REST server from webApp without put in the code a fixed ip? Maybe I'm asking trivial question - I'm not a professional programmer!