You can use an HMI as the landing page for SmartSpace Web. This means that the pages /SmartSpace, and /SmartSpace/Auth will redirect automatically to the published version of this HMI.
When you create (or edit) the HMI, in the Settings tab of the Interface dialog, set the Link property to "_". See Creating a new HMI for further information. The HMI should be given roles such that any valid user can access the page. So if unauthenticated users are allowed to visit SmartSpace, this HMI should be visible to unauthenticated users. See Roles settings for further information.
You can also specify the title of the HMI in code so it will appear on the browser title bar. For example:
window.titleSymbol = "Welcome to SmartSpace for ACME Industries";
This property is copied to document.title as the HMI API is initialized.