Simple subscribe_json call raises a compiler error

[Troon]

I’m guessing you mean this example?

https://esphome.io/custom/custom_component.html#mqtt-custom-component

Assuming you have also included the #include, maybe this post will help:

ArduinoJson v5 or v6?

Well, its seems that the current example is indeed wrong (at least with the current ArduinoJson library)! Here is the corrections that must be made to be able to use JSON MQTT messages: // The original code: //void on_json_message(JsonObject &root) // must be changed to this: void on_json_message(JsonObject root) { if (!root.containsKey("key")) return; int value = root["key"]; // do something with Json Object // publish JSON using lambda syntax // The original c…