diff --git a/web3.js/src/index.js b/web3.js/src/index.js
index bf9db6748c..2a12c49a56 100644
--- a/web3.js/src/index.js
+++ b/web3.js/src/index.js
@@ -1,2 +1,3 @@
+// @flow
 export {Account} from './account';
 export {Connection} from './connection';