#server.open

• Type:

type Open =
  | boolean
  | string
  | string[]
  | {
      target?: string | string[];
      before?: () => Promise<void> | void;
    };

• Default: undefined

server.open configures which page URLs Rsbuild should automatically open in the browser after starting the server.

You can also use the --open option of Rsbuild CLI to open the pages. When using server.open and --open at the same time, --open takes precedence.

#Example

server.open can be set to the following values.

• Open the project's default preview page, which defaults to http://localhost:<port>. If server.host is configured, it defaults to http://<host>:<port>.

export default {
  server: {
    open: true,
  },
};

• Open the specified page:

export default {
  server: {
    open: 'http://localhost:3000',
  },
};

• Open the specified path, equivalent to http://localhost:<port>/home:

export default {
  server: {
    open: '/home',
  },
};

• Open multiple pages:

export default {
  server: {
    open: ['/', '/about'],
  },
};

• Open a non-localhost URL (used with proxy):

export default {
  server: {
    open: 'http://www.example.com',
  },
};

#Port placeholder

The port number that Rsbuild server listens on may change. For example, if the port is in use, Rsbuild will automatically increment the port number until it finds an available port.

To avoid server.open becoming invalid due to port changes, you can use one of the following methods:

• Enable server.strictPort.
• Use the <port> placeholder to refer to the current port number. Rsbuild will replace the placeholder with the actual port number it is listening on.

export default {
  server: {
    open: 'http://localhost:<port>/home',
  },
};

#Specify browser

By default, Rsbuild opens pages in the system's default browser. You can specify which browser to use via the BROWSER environment variable.

#Browser name

Rsbuild uses the open library to open browsers, and supports opening Chrome, Edge, and Firefox:

# Chrome
BROWSER=chrome npx rsbuild dev

# Edge
BROWSER=edge npx rsbuild dev

# Firefox
BROWSER=firefox npx rsbuild dev

On Windows, use cross-env to set environment variables:

npm i cross-env -D
cross-env BROWSER=chrome npx rsbuild dev

You can also refer to the app option of open for additional BROWSER values, such as OS-specific browser names:

# macOS
BROWSER="google chrome" npx rsbuild dev

# Linux
BROWSER="google-chrome" npx rsbuild dev

#Browser arguments

Pass browser arguments through BROWSER_ARGS, with multiple arguments separated by spaces:

BROWSER=chrome BROWSER_ARGS="--incognito" npx rsbuild dev

#AppleScript

On macOS, Rsbuild also supports opening the browser through AppleScript, which allows you to reuse existing browser tabs to open pages.

The following are the browser names supported by AppleScript:

• Google Chrome Canary
• Google Chrome Dev
• Google Chrome Beta
• Google Chrome
• Microsoft Edge
• Brave Browser
• Vivaldi
• Chromium

For example:

BROWSER="Google Chrome Canary" npx rsbuild dev

#Configure environment variable

You can set the BROWSER environment variable in your local .env.local file. This eliminates the need to manually set it each time you start the dev server and prevents affecting other developers on the project.

# .env.local
BROWSER=chrome

#Callback

By using open.before, you can trigger a callback function before opening the page.

export default {
  server: {
    open: {
      before: async () => {
        await doSomeThing();
      },
    },
  },
};

When using open.before, the page URLs can be configured via open.target.

export default {
  server: {
    open: {
      target: ['/', '/about'],
      before: async () => {
        await doSomeThing();
      },
    },
  },
};