> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# server.baseUrl

- **Type:** `string | string[]`
- **Default:** `undefined`

Uniformly set the prefix of server-side routes (commonly used in situations where multiple applications share the same domain name to distinguish traffic).

```ts title="modern.config.ts"
export default defineConfig({
  server: {
    // All generated routes will automatically have the prefix `/base`
    // Generated server-side route file path: dist/route.json
    baseUrl: '/base'

    // Multiple baseUrl
    baseUrl: ['/base-new', '/base-old']
  }
})
```

After running `dev`, you will see that the route access will have the corresponding prefix added:

```bash
  > Local:    http://localhost:8080/base/
  > Network:  http://192.168.0.1:8080/base/
```