diff --git a/src/helper/irs-api.ts b/src/helper/irs-api.ts
index 1092505..a079e08 100644
--- a/src/helper/irs-api.ts
+++ b/src/helper/irs-api.ts
@@ -42,7 +42,8 @@ export const doTransaction = async (
           .digest('hex');
 
         const options = {
-          headers: {'Content-Type': 'application/json'},
+          headers: {'Content-Type': 'application/json',
+                    'X-Merchant': `${merchantId}`},
         };
 
       const mergedDestination = destination;