diff --git a/package.json b/package.json
index 2e9f85f..e64d5c3 100644
--- a/package.json
+++ b/package.json
@@ -3,6 +3,7 @@
   "version": "4.1.2",
   "description": "JSON Schema fluent API",
   "main": "src/FluentJSONSchema.js",
+  "type": "commonjs",
   "types": "types/FluentJSONSchema.d.ts",
   "keywords": [
     "JSON",