diff --git a/scripts/check-is-build-fresh.sh b/scripts/check-is-build-fresh.sh
new file mode 100755
index 00000000..7d4ba7b4
--- /dev/null
+++ b/scripts/check-is-build-fresh.sh
@@ -0,0 +1,12 @@
+#!/usr/bin/env sh
+
+npm run prepare
+git diff --exit-code ./build
+
+if [ $? -eq 0 ]
+then
+  echo "Build dir is up to date"
+else
+  echo "Build dir is out of date. Run 'npm run prepare' and commit changes to update it."
+  exit 1
+fi
\ No newline at end of file