diff --git a/event_routing_backends/helpers.py b/event_routing_backends/helpers.py
index 281640fa..2fe357cc 100644
--- a/event_routing_backends/helpers.py
+++ b/event_routing_backends/helpers.py
@@ -4,6 +4,7 @@
 import datetime
 import logging
 import uuid
+from functools import lru_cache
 from urllib.parse import parse_qs, urlparse
 
 from dateutil.parser import parse
@@ -52,6 +53,7 @@ def get_uuid5(namespace_key, name):
     return uuid.uuid5(base_namespace, name)
 
 
+@lru_cache
 def get_anonymous_user_id(username_or_id, external_type):
     """
     Generate anonymous user id.
@@ -150,6 +152,7 @@ def get_user_email(username_or_id):
     return user_email
 
 
+@lru_cache
 def get_course_from_id(course_id):
     """
     Get Course object using the `course_id`.
diff --git a/event_routing_backends/tests/test_helpers.py b/event_routing_backends/tests/test_helpers.py
index 4e7f560e..9fdac254 100644
--- a/event_routing_backends/tests/test_helpers.py
+++ b/event_routing_backends/tests/test_helpers.py
@@ -53,7 +53,7 @@ def test_get_anonymous_user_id_with_error(self, mocked_external_id):
         mocked_external_id.add_new_user_id.return_value = (None, False)
         # Test that a failure to add an external id raises an error
         with self.assertRaises(ValueError):
-            get_anonymous_user_id('edx', 'XAPI')
+            get_anonymous_user_id('edx2', 'XAPI')
 
         # Test that an unknown user raises this error
         with self.assertRaises(ValueError):