diff --git a/xos/xos/exceptions.py b/xos/xos/exceptions.py
index 9ce38a3..ad24708 100644
--- a/xos/xos/exceptions.py
+++ b/xos/xos/exceptions.py
@@ -54,3 +54,10 @@
         APIException.__init__(self, {"error": "XOSConfigurationError",
                             "specific_error": why,
                             "fields": fields})
+
+class XOSConflictingField(APIException):
+    status_code=400
+    def __init__(self, why="conflicting field", fields={}):
+        APIException.__init__(self, {"error": "XOSMissingField",
+                            "specific_error": why,
+                            "fields": fields})