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

# environments

Rsbuild supports building outputs for multiple environments. You can use `environments` to define different Rsbuild configurations for each environment.

> Please refer to [Multi-environment builds](/guide/advanced/environments.md) for more information.

- **Type:**

```ts
type Environments = {
  [name: string]: EnvironmentConfig;
};
```

- **Default:** `undefined`

## Available options

`EnvironmentConfig` is a subset of the Rsbuild configuration, supporting most options.

Since multiple environments share the same server instance, the following options are currently not supported in `EnvironmentConfig`:

- `root`
- `mode`
- `logLevel`
- `customLogger`
- `environments`
- `server.*`
- `dev.watchFiles`
- `dev.cliShortcuts`

## Example

Configure Rsbuild configuration for `web` (client) and `node` (SSR) environments:

```ts title="rsbuild.config.ts"
export default {
  // Shared configuration for all environments
  resolve: {
    alias: {
      '@common': './src/common',
    },
  },
  environments: {
    // configuration for client
    web: {
      source: {
        entry: {
          index: './src/index.client.js',
        },
      },
      output: {
        target: 'web',
        distPath: {
          root: 'dist/client',
        },
      },
      resolve: {
        alias: {
          '@common1': './src/web/common1',
        },
      },
    },
    // configuration for SSR
    node: {
      source: {
        entry: {
          index: './src/index.server.js',
        },
      },
      output: {
        target: 'node',
        distPath: {
          root: 'dist/server',
        },
      },
      resolve: {
        alias: {
          '@common1': './src/ssr/common1',
        },
      },
    },
  },
};
```

For the `web` environment, the merged Rsbuild configuration is:

```js
const webConfig = {
  source: {
    entry: {
      index: './src/index.client.js',
    },
  },
  output: {
    target: 'web',
    distPath: {
      root: 'dist/client',
    },
  },
  resolve: {
    alias: {
      '@common': './src/common',
      '@common1': './src/web/common1',
    },
  },
};
```

For the `node` environment, the merged Rsbuild configuration is:

```js
const nodeConfig = {
  source: {
    entry: {
      index: './src/index.server.js',
    },
  },
  output: {
    target: 'node',
    distPath: {
      root: 'dist/server',
    },
  },
  resolve: {
    alias: {
      '@common': './src/common',
      '@common1': './src/ssr/common1',
    },
  },
};
```

## Environment name

Since environment names are used in directory names and object property names, we recommend using only letters, numbers, `-`, `_`, and `$`. When other characters are used, Rsbuild will show a warning.

```ts title="rsbuild.config.ts"
export default {
  environments: {
    someName: {}, // ✅
    some_name: {}, // ✅
    'some-name': {}, // ✅
    'some:name': {}, // ❌
  },
};
```