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

# moduleFederation.options

- **Type:** [Rspack.ModuleFederationPluginOptions](https://rspack.rs/plugins/module-federation-plugin#options)
- **Default:** `undefined`

Used to configure the Rspack's Module Federation plugin (Module Federation v1.5).

:::tip
There are several versions of Module Federation implementations. Before using `moduleFederation.options`, please read the [Module Federation guide](/guide/advanced/module-federation.md) to understand the differences between different versions and how to make choices.
:::

## Introduction

When using Module Federation, it is recommended that you use the `moduleFederation.options` option provided by Rsbuild. This option will automatically adjust some related configurations to ensure that the module federation application can run correctly.

When you set the `moduleFederation.options` option, Rsbuild will take the following actions:

- Automatically register the [ModuleFederationPlugin](https://rspack.rs/plugins/module-federation-plugin) plugin, and pass the value of `options` to the plugin.
- Set the default value of the provider's [dev.assetPrefix](/config/dev/asset-prefix.md) configuration to `true`. This will ensure that the static asset URL is correct for remote modules.
- Set the default value of Rspack's [output.uniqueName](https://rspack.rs/config/output#outputuniquename) configuration to `moduleFederation.options.name`, this allows HMR to work as expected.

## Usage

The type of `moduleFederation.options` is exactly the same as the ModuleFederationPlugin plugin of Rspack:

```ts title="rsbuild.config.ts"
export default defineConfig({
  moduleFederation: {
    options: {
      name: 'remote',
      // other options
    },
  },
});
```

This option depends on the runtime package [@module-federation/runtime-tools](https://www.npmjs.com/package/@module-federation/runtime-tools), which provides runtime support for Module Federation. Install it first:


```sh [npm]
npm add @module-federation/runtime-tools
```

```sh [yarn]
yarn add @module-federation/runtime-tools
```

```sh [pnpm]
pnpm add @module-federation/runtime-tools
```

```sh [bun]
bun add @module-federation/runtime-tools
```

```sh [deno]
deno add npm:@module-federation/runtime-tools
```

> Refer to the [ModuleFederationPlugin](https://rspack.rs/plugins/module-federation-plugin) document for all available options.

## Example

Here is a minimal example:

- Remote App

```ts title="remote/rsbuild.config.ts"
import { defineConfig } from '@rsbuild/core';

export default defineConfig({
  server: {
    port: 3002,
  },
  moduleFederation: {
    options: {
      name: 'remote',
      exposes: {
        './Button': './src/Button',
      },
      filename: 'remoteEntry.js',
    },
  },
});
```

- Host App

```ts title="host/rsbuild.config.ts"
import { defineConfig } from '@rsbuild/core';

export default defineConfig({
  server: {
    port: 3002,
  },
  moduleFederation: {
    options: {
      name: 'host',
      remotes: {
        remote: 'remote@http://localhost:3002/remoteEntry.js',
      },
    },
  },
});
```

For more examples, please see:

- [Rsbuild - module-federation example](https://github.com/rstackjs/rstack-examples/tree/main/rsbuild/module-federation)
- [module-federation/module-federation-examples](https://github.com/module-federation/module-federation-examples)