diff --git a/roles/mailman3/templates/settings.py.j2 b/roles/mailman3/templates/settings.py.j2
index d7d33c2fef..029f981533 100644
--- a/roles/mailman3/templates/settings.py.j2
+++ b/roles/mailman3/templates/settings.py.j2
@@ -323,6 +323,9 @@ Q_CLUSTER = {
 #
 REST_FRAMEWORK = {
     'PAGE_SIZE': 10,
+    'DEFAULT_RENDERER_CLASSES': [
+        'rest_framework.renderers.JSONRenderer',
+    ],
     'DEFAULT_FILTER_BACKENDS': (
         'rest_framework.filters.OrderingFilter',
     ),