Does anyone know where the inverter data is actually stored/sent? I see there's a set of "frontends", all accessing the same data (DESSMonitor, ESSMonitor.. etc.), but from where they are actually retrieving that data? Is there a unique "master server"?
I'm trying to write my own data software, reading the raw data, and I don't won't to use the RS232/USB port, but reading the data already sent to the cloud via WiFi.
Thanks.

You're better off reading directly from the inverter

I know, but as I specified in the first post (I don't want to use the local port), that's not what I need to do, as reading the data from the inverter it means using additional hardware, for something that I already have available (I need to make the data available on Internet), unless I can access the inverter IP (wifi interface) someway.

For one, you're at the mercy of whoever the Devs are of the apps, they're mostly uncontactable. From the behaviour I've seen with WatchPower. uptime is a joke. Historical data is hit and miss. Data frequency / resolution is typically 5 minutes or longer

That's OK, the parm i need to read remotely it's the battery SOC (five minutes or even longer is more than enough for my purposes). I found the WiFi module very convenient for the usage... if I'll figure how to get advantage of it. I want to avoid to install an RPi there as I'll add more complexity to the system.