I have a web app that's emailing to a fair number of new and existing users.
I'm looking for a simple way to ensure that my site's reputation doesn't get unnecessarily hurt in a way which will decrease deliverability with ISPs or popular web mails.
Typical scenarios I want to prevent:
- trying to email to an address from which an email previously bounced
- trying again to send a message which a server returned a 5xx error for
- trying to email an address for which the domain isn't registered or doesn't have proper MX records
Is there some tool I can put between my web app and my smtp server that will take care of these and similar issues?