foo@bar.com
Something that I’m surprised a lot of devs don’t know; there are official domains you’re supposed to use for documentation, testing, etc. They are specifically reserved by IANA for these purposes. Originally I think it was just example.com, but they now have a list of all them: <a href="https://www.iana.org/domains/reserved" rel="nofollow">https://www.iana.org/domains/reserved</a>