Site Builder: Test Web Site Customization without Taking the Site Offline / Maintenance Mode

Enabling the Take web site offline for maintenance (Setup > Site Builder > Set Up Web Site) will make all users, including admins, who access the site will see the maintenance message.

To be able for a user to test their deployments, it would be best to test them using the following:

1. Using a Sandbox account for testing.
   Note: Sandbox accounts needs to be purchased.
2. Users can use the Multiple Web Sites feature to create another web site solely for testing.
   Note: This needs to be purchased and enabled on the account.