How to check a domain's MX records (can it receive email?)

Every email address ends in a domain, and that domain has to tell senders where its mail should go. It does that with MX records in DNS. Checking them answers practical questions: is this customer's address real, why has our email stopped arriving since we moved provider, and is this domain set up to receive mail at all?

What an MX record contains

• A mail server name, such as mx1.mailprovider.example.
• A priority number. Lower numbers are tried first; higher ones are backups. Records with the same number share the load.

A domain can have one MX record or several.

Look them up

1. Open the Email Address Validator.
2. Enter one or more email addresses at the domains you want to check.
3. Press “Check mail servers (MX)”. For each domain, it shows the mail servers and priorities, or explains what was found instead.

It also checks each address's format and suggests fixes for common typos such as gmial.com. Only the domain names, the part after the @, are sent for the DNS lookup; the full addresses stay in your browser.

What the results mean

• MX records found: the domain accepts email at those servers. This does not prove a particular mailbox exists, only that the domain takes mail.
• No MX, but the domain has an address: under the email standards, senders may fall back to delivering to the domain's own address. That works occasionally but usually indicates a domain not set up for email.
• Null MX: a single record with priority 0 and a target of “.” is the domain's explicit statement that it accepts no email. Do not send to it.
• Domain does not exist: the address is certainly undeliverable, often a typo.

After changing email provider

When you move to a new email service, its setup instructions give new MX records. Common problems:

• Old MX records left in place alongside the new ones, so some mail goes to the old service.
• Priorities copied wrongly, sending mail to a backup server first.
• DNS changes not yet visible everywhere. Records are cached for their time-to-live, often an hour or more, so allow time before concluding something is broken.
• MX records added at the wrong DNS provider, when the domain's nameservers point elsewhere.

MX is not the whole picture

MX records cover receiving. Whether your sent mail is trusted depends on other DNS records: SPF, DKIM and DMARC, which are TXT records that prove which servers may send for your domain. A domain can receive perfectly and still have its outgoing mail land in spam if those are missing.

Using MX checks on sign-up forms

Checking that a domain has mail servers catches typos and fake domains at sign-up, before you send a confirmation email into the void. It cannot confirm the mailbox itself; only a confirmation email does that. For address format rules, see how to check an email address is valid.