What is MX record?

An MX record is the DNS entry that names the mail servers which receive email for a domain, each with a priority number.

Also called: mail exchanger record.

When anyone sends mail to name@example.com, their server looks up the MX records for example.com and delivers to the server with the lowest priority number, falling back to the others if it is unavailable. A domain with no MX record (and no usable fallback) cannot receive email at all.

For a sender, MX records matter twice. On your own sending domain they decide whether replies arrive: a cold email domain with no MX is a domain that cannot hear back from prospects. On a recipient's domain, the MX lookup is the first step of SMTP verification; no MX usually means every address at the domain is undeliverable.

The MX host also hints at who runs the mailbox. Records pointing at Google or Microsoft show the business uses Google Workspace or Microsoft 365, which changes how verification and inbox placement behave.

Check your own domain's MX, SPF and DMARC together with the free SPF, DMARC and MX checker.