diff --git a/windows/WebViewFetchWindow.cs b/windows/WebViewFetchWindow.cs
index 78d944f..3a2751c 100644
--- a/windows/WebViewFetchWindow.cs
+++ b/windows/WebViewFetchWindow.cs
@@ -42,7 +42,7 @@ internal sealed class WebViewFetchWindow : Window
         msgHandler = (_, args) =>
         {
             _wv.CoreWebView2.WebMessageReceived -= msgHandler;
-            tcs.TrySetResult(args.WebMessageAsString);
+            tcs.TrySetResult(args.WebMessageAsJson);
         };
         _wv.CoreWebView2.WebMessageReceived += msgHandler;