You can do this without masked email too. I have a wildcard alias setup so *@mydomain.tld are accepted, and I have a wildcard sending identity *@mydomain.tld
If you have a sending identity that matches with the address the email was received, on the app and webui it will reply from that address.
Disclaimer: I work at Fastmail, but not on the webui or app.
If you have a sending identity that matches with the address the email was received, on the app and webui it will reply from that address.
Disclaimer: I work at Fastmail, but not on the webui or app.