diff --git a/src/tracker/index.js b/src/tracker/index.js
index 2d9dd18e..b2899e8b 100644
--- a/src/tracker/index.js
+++ b/src/tracker/index.js
@@ -143,7 +143,7 @@
     const callback = window[beforeSend];
 
     if (typeof callback === 'function') {
-      payload = callback(type, payload);
+      payload = await Promise.resolve(callback(type, payload));
     }
 
     if (!payload) return;