Resend

A service for sending the automatic emails a website produces, such as receipts and password resets.

Transactional email is the mail a site sends to one person because of something they did: a confirmation, a receipt, a password reset. It is separate from newsletters, which go to a list.

Resend handles sending that mail and the domain setup that keeps it out of spam folders, including the DNS records that prove a site is allowed to send as its own domain.