A professional, production-grade SMTP server! No it's not. This demo project implements a very simple temporary e-mail, capable of receiving e-mails and storing them in libSQL (locally), sqld, or Turso.
Example deployment: https://sorry.idont.date/
In order to get it to work, run it on a machine with public IP, port 25 exposed, and add all appropriate DNS entries - an MX entry and its corresponding A entry that points to the IP address where eatmail is deployed.