diff --git a/Makefile b/Makefile
index fdebe11..066b44d 100755
--- a/Makefile
+++ b/Makefile
@@ -96,6 +96,7 @@ build: build-bundle build-docs
 
 build-bundle: node_modules
 	$(NODE_BIN)/rollup --config $(CONFIG_PATH)/rollup.js
+	sed -i '1s;^;#! /usr/bin/env node\n\n;' $(TARGET_PATH)/index.js
 
 build-docs: ## generate html docs
 	$(NODE_BIN)/api-extractor run --config $(CONFIG_PATH)/api-extractor.json --local -v