diff --git a/tailbone/api/batch/ordering.py b/tailbone/api/batch/ordering.py
index 1b11194e..204be8ad 100644
--- a/tailbone/api/batch/ordering.py
+++ b/tailbone/api/batch/ordering.py
@@ -86,6 +86,8 @@ class OrderingBatchViews(APIBatchView):
         Sets the mode to "ordering" for the new batch.
         """
         data = dict(data)
+        if not data.get('vendor_uuid'):
+            raise ValueError("You must specify the vendor")
         data['mode'] = self.enum.PURCHASE_BATCH_MODE_ORDERING
         batch = super().create_object(data)
         return batch
diff --git a/tailbone/api/master.py b/tailbone/api/master.py
index 70616484..2d17339e 100644
--- a/tailbone/api/master.py
+++ b/tailbone/api/master.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2023 Lance Edgar
+#  Copyright © 2010-2024 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -31,7 +31,7 @@ from rattail.db.util import get_fieldnames
 
 from cornice import resource, Service
 
-from tailbone.api import APIView, api
+from tailbone.api import APIView
 from tailbone.db import Session
 from tailbone.util import SortColumn
 
@@ -355,9 +355,13 @@ class APIMasterView(APIView):
         data = self.request.json_body
 
         # add instance to session, and return data for it
-        obj = self.create_object(data)
-        self.Session.flush()
-        return self._get(obj)
+        try:
+            obj = self.create_object(data)
+        except Exception as error:
+            return self.json_response({'error': str(error)})
+        else:
+            self.Session.flush()
+            return self._get(obj)
 
     def create_object(self, data):
         """