diff --git a/package.json b/package.json
index f0455eb..2e7c047 100644
--- a/package.json
+++ b/package.json
@@ -9,15 +9,15 @@
     "./package.json": "./package.json",
     ".": {
       "require": "./dist/index.cjs",
-      "import": "./dist/index.js"
+      "import": "./dist/index.mjs"
     },
     "./client": {
       "require": "./dist/client/index.cjs",
-      "import": "./dist/client/index.js"
+      "import": "./dist/client/index.mjs"
     }
   },
-  "main": "./dist/index.js",
-  "module": "./dist/index.js",
+  "main": "./dist/index.mjs",
+  "module": "./dist/index.mjs",
   "types": "./dist/index.d.ts",
   "files": [
     "dist",
@@ -49,7 +49,7 @@
     "eslint": "^8.25.0",
     "nuxt": "3.0.0-rc.12",
     "pnpm": "^7.14.1",
-    "tsup": "6.0.1",
+    "tsup": "6.3.0",
     "typescript": "^4.7.4"
   },
   "eslintConfig": {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 25696ac..006f26a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -14,7 +14,7 @@ importers:
       nuxt: 3.0.0-rc.12
       ohash: ^0.1.5
       pnpm: ^7.14.1
-      tsup: 6.0.1
+      tsup: 6.3.0
       typescript: ^4.7.4
       ufo: ^0.8.6
     dependencies:
@@ -30,7 +30,7 @@ importers:
       eslint: 8.26.0
       nuxt: 3.0.0-rc.12_wyqvi574yv7oiwfeinomdzmc3m
       pnpm: 7.14.1
-      tsup: 6.0.1_typescript@4.8.4
+      tsup: 6.3.0_typescript@4.8.4
       typescript: 4.8.4
 
   docs:
@@ -2695,13 +2695,13 @@ packages:
       semver: 7.3.8
     dev: true
 
-  /bundle-require/3.1.0_esbuild@0.14.54:
+  /bundle-require/3.1.0_esbuild@0.15.12:
     resolution: {integrity: sha512-IIXtAO7fKcwPHNPt9kY/WNVJqy7NDy6YqJvv6ENH0TOZoJ+yjpEsn1w40WKZbR2ibfu5g1rfgJTvmFHpm5aOMA==}
     engines: {node: ^12.20.0 || ^14.13.1 || >=16.0.0}
     peerDependencies:
       esbuild: '>=0.13'
     dependencies:
-      esbuild: 0.14.54
+      esbuild: 0.15.12
       load-tsconfig: 0.2.3
     dev: true
 
@@ -9117,8 +9117,8 @@ packages:
     engines: {node: '>=0.6.x'}
     dev: true
 
-  /tsup/6.0.1_typescript@4.8.4:
-    resolution: {integrity: sha512-2Pl1YkEEvzfg4aYgwUILaHV0wwZQKO7mNHMQChyzdCNlQqf11eug7gWk86XCb3CvRofCXBX87x73BTGjyS3cOQ==}
+  /tsup/6.3.0_typescript@4.8.4:
+    resolution: {integrity: sha512-IaNQO/o1rFgadLhNonVKNCT2cks+vvnWX3DnL8sB87lBDqRvJXHENr5lSPJlqwplUlDxSwZK8dSg87rgBu6Emw==}
     engines: {node: '>=14'}
     hasBin: true
     peerDependencies:
@@ -9133,11 +9133,11 @@ packages:
       typescript:
         optional: true
     dependencies:
-      bundle-require: 3.1.0_esbuild@0.14.54
+      bundle-require: 3.1.0_esbuild@0.15.12
       cac: 6.7.14
       chokidar: 3.5.3
       debug: 4.3.4
-      esbuild: 0.14.54
+      esbuild: 0.15.12
       execa: 5.1.1
       globby: 11.1.0
       joycon: 3.1.1
diff --git a/tsup.config.ts b/tsup.config.ts
index e8b5a29..73d3a7e 100644
--- a/tsup.config.ts
+++ b/tsup.config.ts
@@ -7,4 +7,10 @@ export default defineConfig({
   clean: true,
   external: ['#app'],
   dts: true,
+  // @ts-expect-error: Missing type
+  outExtension({ format }) {
+    return {
+      js: format === 'esm' ? '.mjs' : `.${format}`,
+    }
+  },
 })