diff --git a/package.json b/package.json
index 7b73de4..0cece0b 100644
--- a/package.json
+++ b/package.json
@@ -91,7 +91,8 @@
     "react-test-renderer": "^16.4.1",
     "refunk": "^3.0.1",
     "rimraf": "^2.6.2",
-    "sinon": "^6.0.0"
+    "sinon": "^6.0.0",
+    "webpack-dev-middleware": "3.6.0"
   },
   "x0": {
     "title": "x0",