I use a subdomain; making your main domain a catch-all will eventually result in a deluge of spam.
Instead of [everything]@example.com, I set up [everything]@yo.example.com. Discovering subdomains is much harder and the one time I encountered a form that didn't like a subdomain, I just made a forwarding address on my main domain.
Using Fastmail's rules, I have a setup where every message arriving to @yo.example.com gets shunted into a folder unless there's a different rule putting it somewhere else.
Is this because you don’t publish MX records in DNS for the subdomains and the default setting on the main domain is to accept only specific addresses (and reject catch-all addresses)?
Instead of [everything]@example.com, I set up [everything]@yo.example.com. Discovering subdomains is much harder and the one time I encountered a form that didn't like a subdomain, I just made a forwarding address on my main domain.
Using Fastmail's rules, I have a setup where every message arriving to @yo.example.com gets shunted into a folder unless there's a different rule putting it somewhere else.