diff --git a/examples/v3.0/callback-example.yaml b/examples/v3.0/callback-example.yaml
index c698b9704c..ecd271b95c 100644
--- a/examples/v3.0/callback-example.yaml
+++ b/examples/v3.0/callback-example.yaml
@@ -32,7 +32,7 @@ paths:
         onData:
           # when data is sent, it will be sent to the `callbackUrl` provided
           # when making the subscription PLUS the suffix `/data`
-          {$request.query.callbackUrl}/data:
+          '{$request.query.callbackUrl}/data':
             post:
               requestBody:
                 description: subscription payload