diff --git a/package.json b/package.json
index 6f37286..a3470ed 100644
--- a/package.json
+++ b/package.json
@@ -54,6 +54,7 @@
     "@babel/eslint-parser": "^7.29.7",
     "@babel/preset-env": "^7.29.7",
     "@babel/register": "^7.29.7",
+    "@rolldown/plugin-babel": "0.2.3",
     "ava": "^3.0.0",
     "babel-plugin-add-module-exports": "^1.0.4",
     "babel-plugin-istanbul": "^8.0.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 7d721b4..8f302f6 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -23,6 +23,9 @@ importers:
       '@babel/register':
         specifier: ^7.29.7
         version: 7.29.7(@babel/core@7.29.7)
+      '@rolldown/plugin-babel':
+        specifier: 0.2.3
+        version: 0.2.3(@babel/core@7.29.7)(rolldown@1.1.1)
       ava:
         specifier: ^3.0.0
         version: 3.15.0
@@ -819,6 +822,23 @@ packages:
     cpu: [x64]
     os: [win32]
 
+  '@rolldown/plugin-babel@0.2.3':
+    resolution: {integrity: sha512-+zEk16yGlz1F9STiRr6uG9hmIXb6nprjLczV/htGptYuLoCuxb+itZ03RKCEeOhBpDDd1NU7qF6x1VLMUp62bw==}
+    engines: {node: '>=22.12.0 || ^24.0.0'}
+    peerDependencies:
+      '@babel/core': ^7.29.0 || ^8.0.0-rc.1
+      '@babel/plugin-transform-runtime': ^7.29.0 || ^8.0.0-rc.1
+      '@babel/runtime': ^7.27.0 || ^8.0.0-rc.1
+      rolldown: ^1.0.0-rc.5
+      vite: ^8.0.0
+    peerDependenciesMeta:
+      '@babel/plugin-transform-runtime':
+        optional: true
+      '@babel/runtime':
+        optional: true
+      vite:
+        optional: true
+
   '@rolldown/pluginutils@1.0.1':
     resolution: {integrity: sha512-2j9bGt5Jh8hj+vPtgzPtl72j0yRxHAyumoo6TNfAjsLB04UtpSvPbPcDcBMxz7n+9CYB0c1GxQFxYRg2jimqGw==}
 
@@ -4909,6 +4929,12 @@ snapshots:
   '@rolldown/binding-win32-x64-msvc@1.1.1':
     optional: true
 
+  '@rolldown/plugin-babel@0.2.3(@babel/core@7.29.7)(rolldown@1.1.1)':
+    dependencies:
+      '@babel/core': 7.29.7
+      picomatch: 4.0.4
+      rolldown: 1.1.1
+
   '@rolldown/pluginutils@1.0.1': {}
 
   '@rtsao/scc@1.1.0': {}
diff --git a/tsdown.config.ts b/tsdown.config.ts
index d975eff..5537bc0 100644
--- a/tsdown.config.ts
+++ b/tsdown.config.ts
@@ -1,4 +1,5 @@
 import { defineConfig } from 'tsdown';
+import babel from '@rolldown/plugin-babel'
 
 const banner = `Bowser - a browser detector
 https://github.com/lancedikson/bowser
@@ -9,6 +10,23 @@ export default defineConfig([
   {
     entry: ['src/bowser.js'],
     format: ['umd'],
+    plugins:[
+      babel({
+        presets: [['@babel/preset-env', {
+          useBuiltIns: 'usage',
+          corejs: '3',
+          modules: 'cjs',
+          loose: true,
+          targets: {
+            ie: '8',
+            browsers: '>2%'
+          }
+        }]],
+        "plugins": [
+          "add-module-exports"
+        ]
+      })
+    ],
     outDir: 'dist/umd', // universal module definition
     globalName: 'Bowser',
     dts: false,