Wanted to add something: at Mailgun, we always make a point to have a few engineers available to our customers every day. The very same people who've built our message queue, our parsing services, our analytics package, will be answering your questions in case they turn out to be too hardcore for our support team to handle.<p>Moreover, we invite customers of competing services to reach out to us if they have any email-related complication/issue at work. Will be happy to help.