I know with Mastodon you can use WEB_DOMAIN https://docs.joinmastodon.org/admin/config/#web_domain and LOCAL_DOMAIN so you could be @edent@shkspr.mobi but have the Mastodon interface on actpubmicroblog.shkspr.mobi if you wanted Why that subdomain? Well, Mastodon is currently the major Activity Pub Microblogging software so it's reasonably generic for reuse: just remember that Mastodon alternatives are not necessarily 100% compatible (and vice versa: some now support quote posts but Mastodon doesn't so the UI is a bit different) I've got no idea how well the user handles and webfinger will work with Pixelfed etc: but as Look Around You taught us "A scientist conducted an experiment..." 🙂