diff --git a/.changeset/odd-lizards-appear.md b/.changeset/odd-lizards-appear.md
new file mode 100644
index 0000000..05128a9
--- /dev/null
+++ b/.changeset/odd-lizards-appear.md
@@ -0,0 +1,5 @@
+---
+"@aiou/webext-template": patch
+---
+
+bundle all packages into background bundle
diff --git a/tsup.config.ts b/tsup.config.ts
index 73251de..77cc52e 100644
--- a/tsup.config.ts
+++ b/tsup.config.ts
@@ -7,6 +7,8 @@ export default defineConfig(() => ({
     ...(isDev ? { mv3client: './scripts/client.ts' } : {}),
   },
   outDir: 'extension/dist',
+  // bundle all imported packages into bundle(background.ts)
+  noExternal: [/./],
   format: ['esm'],
   target: 'esnext',
   ignoreWatch: ['**/extension/**'],