Question 1

What are MX records?

Accepted Answer

MX (mail exchange) records tell the internet which servers accept inbound email for your domain. If your domain has no MX records, most mail providers treat it as not accepting mail and may reject or discard messages addressed to it.

Question 2

What does this MX checker actually test?

Accepted Answer

It looks up your MX records, resolves each mail server to its IP address, and checks the reverse DNS (PTR) record for those IPs. A domain whose MX records point to servers that do not resolve to an IP, or that have no PTR, is a common cause of mail being rejected or treated as spam.

Question 3

Why do MX and PTR matter for deliverability?

Accepted Answer

Receiving mail servers verify that your MX records point to real, resolvable hosts and that those hosts have a matching reverse DNS (PTR) record. Missing MX records, MX hosts that do not resolve, or missing PTR are among the fastest ways to get mail rejected or pushed to the spam folder before SPF, DKIM and DMARC are even evaluated.

Question 4

My domain has no MX records. What should I do?

Accepted Answer

If you send or receive mail on the domain, add MX records for your mail provider (Google Workspace, Microsoft 365, your host's mail server, or an ESP like SendGrid or Postmark). If the domain never handles mail, consider adding a null MX or documenting that it is not a mail domain.

Question 5

Is this MX checker free?

Accepted Answer

Yes. The MX, PTR and STARTTLS check is free and requires no signup. You can optionally add an email to run and save the full deliverability audit, which adds SPF, DKIM, DMARC, blocklist and IP reputation checks.

MX record checker

Check the whole domain, not just the MX

MX is only one signal