How do you ensure 100% transactional email uptime?

Question

Elasticemail went out today and left some of my services high and dry. How do people deal with transactional emails that MUST go out? Thinking about building a fall-back to other services, but was curious if anyone had suggestions. Thanks!

pwg · Accepted Answer

SMTP has built in reliability and redundancy. You just setup multiple MX records in the DNS for the domain with differing priorities, referencing physically different systems that can receive email for the domain, and sending systems (if standards compliant) are supposed to work their way down the list if the primary MX server fails until delivery is successful.At which point, you only get non-delivery if all backup MX entries are offline along with the primary.