---
title: externals
configName: output.externals
---

# output.externals

- **Type:**

```ts
type Externals =
  | string
  | object
  | function
  | RegExp
  | Array<string | object | function | RegExp>;
```

- **Default:** `undefined`

At build time, prevent some `import` dependencies from being packed into bundles in your code, and instead fetch them externally at runtime.

import RsbuildConig from '@site-docs-en/components/rsbuild-config-tooltip';

<RsbuildConig />
