diff --git a/src/scwidgets/exercise/_widget_exercise_registry.py b/src/scwidgets/exercise/_widget_exercise_registry.py
index 030a8be..1a82adf 100644
--- a/src/scwidgets/exercise/_widget_exercise_registry.py
+++ b/src/scwidgets/exercise/_widget_exercise_registry.py
@@ -124,8 +124,8 @@ def is_valid_filename(prefix, filename):
         ) and (filename.endswith("json"))
 
     @staticmethod
-    def standardize_filename(filename):
-        return filename
+    def standardize_filename(filename: str) -> str:
+        return filename.lower().replace(" ", "_")
 
     @property
     def filename_prefix(self):