diff --git a/lc-esp-sdk/src/main/java/lc/esp/sdk/ESPMessage.java b/lc-esp-sdk/src/main/java/lc/esp/sdk/ESPMessage.java
index 42cd3519458c0de149c1bf1538f2997fefac1782..22a73b090745bb101c4380b0b7d5e610225a087b 100644
--- a/lc-esp-sdk/src/main/java/lc/esp/sdk/ESPMessage.java
+++ b/lc-esp-sdk/src/main/java/lc/esp/sdk/ESPMessage.java
@@ -70,6 +70,9 @@ public class ESPMessage {
         return o;
     }
 
+    /**
+     * Return the payload of this message in JSON format.
+     */
     public JSONObject getPayload() {
         return payload;
     }