diff --git a/package.json b/package.json
index fc844bc..d3c5b0f 100644
--- a/package.json
+++ b/package.json
@@ -13,6 +13,7 @@
     "url": "http://bost.ocks.org/mike"
   },
   "main": "build/d3-tile.js",
+  "module": "index",
   "jsnext:main": "index",
   "repository": {
     "type": "git",