@lamp Can you explain the problem you're trying to solve? I might be able to accommodate it.

Currently all URLs, including properties that ActivityPub typically uses URLs for, are generated at runtime based on a configuration hostname loaded at startup. So, you can stop the server and change one line and start it again and serve it on another domain. But during runtime it cannot server on two domains simultaneously, at least not the activitypub stuff. Does that work for you?