diff --git a/app/templates/base.html.j2 b/app/templates/base.html.j2
index d5b361b7..ce571e90 100644
--- a/app/templates/base.html.j2
+++ b/app/templates/base.html.j2
@@ -24,6 +24,7 @@
         {% endfor %}
       ];
     </script>
+    <script src="{{ url_for('static', filename='js/jsondiffpatch.umd.js') }}"></script>
     <script src="{{ url_for('static', filename='js/polls.js') }}"></script>
     {% endif %}
     <script src="{{ url_for('static', filename='js/list.js') }}"></script>