diff --git a/packages/foundkey-js/package.json b/packages/foundkey-js/package.json
index b5c54697c..6c541f9fe 100644
--- a/packages/foundkey-js/package.json
+++ b/packages/foundkey-js/package.json
@@ -2,6 +2,7 @@
 	"name": "foundkey-js",
 	"version": "13.0.0-preview1",
 	"description": "Fork of misskey-js for Foundkey",
+	"type": "module",
 	"main": "./built/index.js",
 	"types": "./built/index.d.ts",
 	"scripts": {