You can set up a wildcard/catchall alias instead of having to manually create an actual alias for each service. Someone can send email to anything@yourdomain.com and it will go to your inbox.
You can also send with a wildcard - the big desktop email clients, as well as the FastMail web interface, as well as FairEmail on Android all let you type something for the part before the @, so you can send from anything@yourdomain.com.
I have different categories per services: paid services go to @paid.mydomain.tld, social logins go to @social.mydomain.tld etc. So that means something like paypal@paid.mydomain.tld or twitter@social.mydomain.tld.
That does seem clean, but I would worry about normal people being confused by it. Having (business's name)@myname.com already gets a lot of questions / confirmations / confused responses.
Yes, doing that certainly does raise a lot of questions from people. They often pause and ask for clarification. Also, I've come to learn that some company's email validators do not accept `.email`. Thankfully this is a rare occurrence. And when it does happen, I've always been successful in bypassing it. I'm too attracted to the appeal of `.email`, so I happily put up with it.
I'm very interested about the aliases, but I'm not sure that I understand it correctly. I have a example00@fastmail.com address, does this mean that I can also register example01@fastmail.com and example02@fastmail.com as an alias on my account, and it will seem like I have three accounts and recipients will never known about example00@fastmail.com if I send from one of the two aliases? Do I then also "own" example01@fastmail.com and example02@fastmail.com in the same way I "own" example00@fastmail.com while a customer?. If understood correctly, I could register an alias for mailing lists, and disable it if too much spam is received without ruining my main address.
Yes, exactly. As long as the name is available. They all forward to the same inbox and if you use the web interface then fastmail knows to reply from the same alias as well.