diff --git a/pkgs/servers/mail/mailman/hyperkitty.nix b/pkgs/servers/mail/mailman/hyperkitty.nix
index 758433ba3a4..7e696f6d27f 100644
--- a/pkgs/servers/mail/mailman/hyperkitty.nix
+++ b/pkgs/servers/mail/mailman/hyperkitty.nix
@@ -15,14 +15,19 @@ buildPythonPackage rec {
   };
 
   nativeBuildInputs = [ isort ];
-  buildInputs = [ coverage mock ];
   propagatedBuildInputs = [
     robot-detection django_extensions rjsmin cssmin django-mailman3
     django-haystack flufl_lock networkx dateutil defusedxml
     django-paintstore djangorestframework django django-q
-    django_compressor beautifulsoup4 six psycopg2 whoosh isort elasticsearch
+    django_compressor six psycopg2 isort
   ];
 
+  # Some of these are optional runtime dependencies that are not
+  # listed as dependencies in setup.py.  To use these, they should be
+  # dependencies of the Django Python environment, but not of
+  # HyperKitty so they're not included for people who don't need them.
+  checkInputs = [ beautifulsoup4 coverage elasticsearch mock whoosh ];
+
   checkPhase = ''
     cd $NIX_BUILD_TOP/$sourceRoot
     PYTHONPATH=.:$PYTHONPATH python example_project/manage.py test \