diff --git a/api-reference/openapi.json b/api-reference/openapi.json
index dc6370c..73fc537 100644
--- a/api-reference/openapi.json
+++ b/api-reference/openapi.json
@@ -641,13 +641,18 @@
           "order_id": {
             "type": "string"
           },
-          "transaction": {
+          "initiate_transaction": {
             "$ref": "#/components/schemas/EVMTransaction"
           },
+          "approval_transaction": {
+            "$ref": "#/components/schemas/EVMTransaction",
+            "nullable": true,
+            "description": "Can be null if no approval is needed."
+          },
           "typed_data": {
             "$ref": "#/components/schemas/EVMTypedData"
           }
-        }  
+        }
       },
       "StarknetTransaction": {
         "type": "object",