# Implementation

- Type: `string`
- Required: No
- Default value: `undefined`

The `implementation` option is used to modify the actual bundler runtime version. It should be set to the path of `@module-federation/runtime-tools`.

When working with Module Federation, the runtime is responsible for handling the loading and sharing of remote modules. By default, the bundler uses a specific version of the runtime that is compatible with its version. However, in some cases, you might need to use a different version of the runtime or a custom implementation.

By specifying the `implementation` option, you can provide a path to the desired runtime implementation. This is particularly useful if you need to use features from a newer or older version of the runtime that are not available in the default version provided by the bundler.

For example, if you want to use a specific version of `@module-federation/runtime-tools`, you can set the `implementation` option in your configuration file:

```javascript
module.exports = {
  // ...other configurations
  plugins: [
    new ModuleFederation({
      // ...other Module Federation options
      implementation: require.resolve('@module-federation/runtime-tools'),
    }),
  ],
};
```