diff --git a/mjs_fs/api_mqtt.js b/mjs_fs/api_mqtt.js
index a4847f4..dd29bb7 100644
--- a/mjs_fs/api_mqtt.js
+++ b/mjs_fs/api_mqtt.js
@@ -40,7 +40,8 @@ let MQTT = {
   // ```
   pub: function(t, m, qos, retain) {
     qos = qos || 0;
-    return this._pub(t, m, m.length, qos, retain || false);
+    let message = typeof m === "number" ? JSON.stringify( m ) : m;
+    return this._pub(t, message, message.length, qos, retain || false);
   },
 
   // ## **`MQTT.setEventHandler(handler, userdata)`**