API-Designer.md

@@ -399,6 +399,22 @@ Example:
     </api>
 ```
 
+#### Setting Headers
+To set headers to the request add headers node inside rest node.
+
+Example:
+```
+<?xml version="1.0" ?>
+    <api method="post">
+        <rest method="post">
+            <url>https://sheets.googleapis.com/v4/spreadsheets</url>
+            <headers>
+		<header name="Content-Type" value="application/json"> </header>
+	    </headers>
+         </rest>
+     </api>
+
+
 #### SOAP Support 
 
 ```