I’m interested in setting up my own instances for Lemmy, Mastodon, and Matrix.
Can I use the same https://domain.tld for all of them without any subdomains?
For example:
lemmyuser@mydomain.tld
mastodonuser@mydomain.tld
matrixuser@mydomain.tld
Will this work across all of my self-hosted instances, or do I need to append a subdomain for each, e.g., lemmyuser@lemmy.mydomain.tld?
Matrix (or even easier XMPP) can coexist on the same domain with Lemmy or Mastodon, but with two ActivityPub services that is AFAIK not possible.
All those services use a protocol named WebFinger that allows for having the servers in different domains but showing the users as being in a main domain. For example, my self-hosted Synapse server is at matrix.domain.tld, but my users are all like user@domain.tld.
Unfortunately I don’t really know how to set it all up manually, I just let Yumohost take care of managing it.