But can you host it ? (Can't find much on federation). I use fastmail and a custom domain for my email. If I'm unhappy with the service I can migrate or host i

But can you host it ? (Can't find much on federation). I use fastmail and a custom domain for my email. If I'm unhappy with the service I can migrate or host it. If you can't leave having your own domain is not much help. Note: I believe webfinger are supported by Mastodon too, so not so special of a feature.