diff --git a/latexonhttp/resources/json_api.py b/latexonhttp/resources/json_api.py
index e71c0d4..23394a2 100644
--- a/latexonhttp/resources/json_api.py
+++ b/latexonhttp/resources/json_api.py
@@ -17,6 +17,8 @@
 
 
 def parse_json_resources_spec(json_payload):
+    if not json_payload:
+        return None, None
     json_spec = {}
 
     # Select / copy several keys.