diff --git a/pkgs/development/python-modules/roadrecon/default.nix b/pkgs/development/python-modules/roadrecon/default.nix
index 4bbbf63be2ed..75c3da3bd630 100644
--- a/pkgs/development/python-modules/roadrecon/default.nix
+++ b/pkgs/development/python-modules/roadrecon/default.nix
@@ -25,7 +25,10 @@ buildPythonPackage rec {
     hash = "sha256-fvfwgUqVr74JdL3dteX0UXbALva3vWQWEpotk8QQAiI=";
   };
 
-  pythonRelaxDeps = [ "flask" ];
+  pythonRelaxDeps = [
+    "marshmallow"
+    "flask"
+  ];
 
   build-system = [ setuptools ];