diff --git a/shell.nix b/shell.nix
index 3ea215d02cfbbb0e66a6990183289fc003792947..1bb9ad03040d740c25cad830d00fd17063300d34 100644
--- a/shell.nix
+++ b/shell.nix
@@ -117,6 +117,7 @@ pkgs.mkShell {
     pkgs.closurecompiler
     pkgs.minify
     pkgs.nodejs
+    python  # needed for msgpack etc
     repl
     serve
     pkgs.pulp