Untitled

bool on = true;

server.on("/get/scan", HTTP_GET, [](AsyncWebServerRequest *request){
    String onParam = request->arg("on");
    on = onParam.toInt() == 1;

    String response = "{\"modulation\":\"Modulation_" + String(on) + "\"}";
    request->send(200, "application/json", response);
  });