Can you use the same domain/username for different fediverse services?
Is there a way to set it up so user@example.com can be a lemmy account and also a mastadon account? I seen people using subdomains like user@lemmy.example.com and user@mastadon.example.com is this nessasary? Could u also set up a matrix account with the same user@example.com? If not what woukd be requured to change to make this possible?
You do it via a webfinger. But the service itself has to request a specific resource in order to route it correctly. For example, mastodon and pixelfed ask for the same resource, so both services will end up getting the same service's account.
Has anyone actually done it? I cant seem to find any decent guides on how to do it?
Each fediverse service is different. Matrix has it's own webfinger configuration, as does diaspora, and mastodon. However, it looks like all ActivityPub services use the same webfinger configuration, which means that this method doesn't work for donations trying to reference user@domain.tld for activitypub. I would presume that the first AP service you have listed in the response is going to be the account that each AP service will federate with.
Here's a little bit about what I'm talking about:
https://www.hanselman.com/blog/use-your-own-user-domain-for-mastodon-discoverability-with-the-webfinger-protocol-without-hosting-a-server
https://github.com/pixelfed/pixelfed/issues/3563
No, not in the example that you've set up. The username is always @user@domain. This is like asking if you can have the same email address on Gmail and Hotmail or whatever. You can have the same user part, but not the domain.
People that have used user@x.domain and also user@y.domain is allowed because they're different domain names.
So u cant just do some weird routing rules and make it work.
Technically you sort of can do that with email. Most providers let you verify you own the other email and then use the other provider's SMTP to send from a different address.
I don't know if there's a service that provides both functions. I'm sure there's a way to do it - Lemmy posts are already accessible through Mastodon. Currently, I assume you would need the instance itself to offer both services under one account.
Well i recently got myself a new server and domain and was going to self host all my things though it would be cool to have the same username and domain across services without needing to do subdomain shenanigans.