Which newsgroup for json parsing?

Hi all,
I am trying to parse a json string received through MQTT from a "Shelly Plug S", e.g.
{"id":0, "source":"button", "output":true, "apower":0.0, "voltage":237.9, "current":0.000, "aenergy":{"total":0.000,"by_minute":[0.000,0.000,0.000],"minute_ts":1715172119},"temperature":{"tC":41.1, "tF":106.0}}
I am trying to use libjson-glib but I can't figure out what to use as the first argument to json_gobject_from_data()!
I am also looking at libjson-c but cannot find any examples that could guide me.
Thanks in advance,
Josef