Map Multiple Domains – Change the URL and replace the token

Change the URL definition defines the domain for which the preview opens when the preview button is enabled in the GTM user interface. One of the main advantages of server-side markup is that a first-party context can be established between the sending site and the endpoint of the server-side markup itself. Naturally, any additional sites created to collect data at the server-side markup endpoint place additional burden on the running instances in the stack and on your monthly bill. By default, however, only one user domain is associated with a given markup server. For a domain to be in first-party context with another domain, both must share a common top-level domain name under private control. This is because there is only one domain that can be configured as a branding server URL in Container Management. The underlying server infrastructure remains the same: assigning custom domains does not require additional servers to be added to the configuration or anything like that.