Fastmail can fetch new messages and send mail through Gmail: https://www.fastmail.help/hc/en-us/articles/1500000278022-Using-other-email-addresses https://www.

Fastmail can fetch new messages and send mail through Gmail: https://www.fastmail.help/hc/en-us/articles/1500000278022-Using-other-email-addresses https://www.fastmail.help/hc/en-us/articles/1500000278022-Us... Use a "wildcard alias" to receive any e-mail sent to a custom domain: https://www.fastmail.help/hc/en-us/articles/1500000277942-Catchall-Wildcard-aliases https://www.fastmail.help/hc/en-us/articles/1500000277942-Ca...