diff --git a/.changeset/late-beds-call.md b/.changeset/late-beds-call.md
new file mode 100644
index 0000000..042f286
--- /dev/null
+++ b/.changeset/late-beds-call.md
@@ -0,0 +1,5 @@
+---
+'fireworkers': patch
+---
+
+set pkg.sideEffects to false
diff --git a/package.json b/package.json
index a5e1109..db971ae 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "fireworkers",
   "version": "0.1.1",
   "description": "Use Cloud Firestore inside Cloudflare Workers.",
+  "sideEffects": false,
   "type": "module",
   "module": "dist/index.js",
   "types": "dist/types/index.d.ts",