diff --git a/examples/OneOpenAir/OneOpenAir.ino b/examples/OneOpenAir/OneOpenAir.ino
index 448284d..7230e14 100644
--- a/examples/OneOpenAir/OneOpenAir.ino
+++ b/examples/OneOpenAir/OneOpenAir.ino
@@ -1150,6 +1150,9 @@ static void sendDataToServer(void) {
         "Online mode and isPostToAirGradient = true: watchdog reset");
     Serial.println();
   }
+
+  /** Log current free heap size */
+  Serial.printf("Free heap: %u\n", ESP.getFreeHeap());
 }
 
 static void tempHumUpdate(void) {
diff --git a/src/AgValue.cpp b/src/AgValue.cpp
index 769fddd..ab3e731 100644
--- a/src/AgValue.cpp
+++ b/src/AgValue.cpp
@@ -612,6 +612,10 @@ String Measurements::toString(bool localServer, AgFirmwareMode fwMode, int rssi,
     root["serialno"] = ag.deviceId();
     root["firmware"] = ag.getVersion();
     root["model"] = AgFirmwareModeName(fwMode);
+  } else {
+#ifndef ESP8266
+    root["freeHeap"] = ESP.getFreeHeap();
+#endif
   }
 
   String result = JSON.stringify(root);