A free MX record lookup that resolves every MX record for a domain with its priority, flags Null MX, and identifies the mail provider behind the host. The MX record lookup tool free of signup and free of caching.
This free MX record checker asks authoritative nameservers which servers accept mail for a domain, and in what order. It is the first query to run when mail stops arriving, because every other mail check assumes an MX record lookup already passed.
MX records are a prioritised list rather than a single answer. Lower priority numbers are tried first and equal numbers load-balance, so this free MX record checker lists every host with its number — the backup MX is where mail ends up when the primary is down.
This MX lookup also separates a missing MX from a Null MX. A domain with no records may still receive mail through inconsistent implicit-MX fallback; a Null MX is an explicit refusal. This MX record lookup that reports both as empty is losing the distinction that matters.
aspmx.l.google.com and its backups. An MX record lookup shows all five hosts with their priorities.
mail.protection.outlook.com. A single host, so our MX lookup result is short and unambiguous.
A self-hosted or niche provider. An MX record lookup reports the hostnames; the provider is whatever runs them.
What it reads
An MX record lookup asks authoritative nameservers which servers accept mail for a domain, and in what order. It is the first query to run when mail stops arriving, because every later check assumes our MX record lookup already passed.
Each MX record carries a hostname and a priority number. Lower numbers are tried first, and equal numbers are load-balanced. An MX record lookup that shows only the first host is hiding the failover path.
Our free MX record checker lists every host with its priority, because the backup MX is where mail ends up when the primary is down.
A domain with no MX records cannot receive mail through the usual path. Our MX lookup reports that as a definitive finding rather than an empty result.
SMTP historically falls back to the domain's A record when no MX exists. That implicit-MX behaviour is inconsistent across receivers, so treat a missing MX as broken rather than as a working fallback.
A single MX record pointing at a dot is a Null MX: the domain is stating it accepts no mail at all. The free MX record checker that reports this as a normal record is misreading it.
Null MX is correct configuration for domains that only serve websites, and it stops senders wasting delivery attempts.
aspmx.l.google.com means Google Workspace, mail.protection.outlook.com means Microsoft 365. An MX lookup effectively identifies who runs mail for a domain.
That is useful before outreach, and an MX lookup is the fastest way to confirm a migration actually completed.
Findings
Four outcomes, each with a different next step.
The domain is configured to receive mail. If delivery is still failing, the cause is downstream: the mailbox, authentication, or reputation.
An MX lookup rules out one whole class of problem in a second, which is why it belongs first in the sequence.
Nothing will arrive through the normal path. Either the domain never had mail configured or the records were removed during a migration.
Publish MX records before anything else; a free MX record checker cannot find what was never created.
The domain is explicitly refusing mail. This is intentional configuration, not a fault.
Do not send. An address on a Null MX domain cannot receive anything, whatever the local part looks like.
The classic half-finished migration. Old MX records keep routing mail to a mailbox nobody reads.
This is why an MX lookup belongs in every migration checklist, run after propagation rather than before.
When to run it
MX is the layer everything above it assumes is working, and nothing tells you when it stops.
First query, every time. Our MX record lookup takes a second and eliminates the most common cause of a domain-wide mail failure.
If this MX lookup is clean, move on to SPF, DMARC, and the mailbox itself.
Old and new MX records coexist for the length of the TTL. Our free MX record checker tells you which one authoritative nameservers are actually serving right now.
Lower TTLs a day ahead so the cutover is minutes rather than hours.
A domain with no mail route will bounce every address on it. This free MX record checker on the domain is faster than verifying a hundred addresses individually.
For the addresses themselves, use Bulk Email Verification once our MX lookup confirms the domain can receive anything at all.
The MX host identifies the mail provider, which tells you something about the organisation's stack before the first conversation.
An MX lookup with no signup makes that a two-second check rather than a research task.
Limits
MX is domain-level routing. Four things sit outside it.
MX records serve every address at the domain, live and dead alike. This MX record lookup confirms the domain can receive mail, not that anyone reads a particular inbox.
For that, use Email Verifier; our MX record lookup and a mailbox probe answer different halves of the question.
SPF, DKIM, and DMARC live in different records. A perfect MX lookup result says nothing about whether your mail will pass alignment.
Those are separate queries with separate tools.
Correct MX records mean mail can be routed. Whether it lands in the inbox depends on reputation, content, and complaint history.
A free MX record checker is a precondition check, not a delivery prediction.
An MX record lookup queries authoritative nameservers. Your own machine and your ISP may still be serving something older until the TTL expires.
That gap is normal and is not something an MX lookup can shorten.
Reference
MX records are defined by the IETF, and the tools beside this MX lookup interpret what an MX lookup returns.
The IETF's RFC 5321 defines how senders resolve MX records, the priority ordering, and the implicit-MX fallback this MX lookup deliberately reports separately.
Null MX is defined in RFC 7505, which is why the free MX record checker treats it as its own finding.
A free MX record checker covers routing. The SPF Checker and DMARC checker cover authentication, which lives in different records entirely.
Run all three before a campaign; an MX lookup alone is one third of the picture.
A working mail route is not a working mailbox. The Email Verifier runs a live SMTP probe against the specific address.
A MX record lookup tool free of signup answers the domain question; the verifier answers the person question.
Nineteen free tools alongside the paid AI features, none of them requiring an account.
Free Tools
Free DNS record lookup for any domain: A, AAAA, MX, TXT, NS, CNAME, SOA resolved live from authoritative nameservers. DNS record lookup tool, free, no signup.
Domain or infrastructure evidence — not mailbox proof.
Email Verify Tools
Free email validator for address syntax and published MX records. Run an email syntax and MX check instantly, without claiming SMTP mailbox proof.
Recipient evidence — not sender or DNS configuration.
Email Verify Tools
Check if an email address is valid with a free email verifier, no signup — syntax, MX, SMTP mailbox, disposable, role and catch-all checks.
Free Tools
Free SPF record checker: resolve the live SPF record for any domain, count DNS lookups, and validate the syntax. SPF record checker and validator, no signup.
Free Tools
Free DMARC record checker: resolve the live DMARC record for any domain, parse every tag, and report the effective policy. DMARC record checker and validator, no signup.
Email Tools
Free email deliverability test: send one message and get authentication, DNS, spam-filter, blacklist, header, and content scores. A free email inbox placement test, no signup.
Sender or message diagnostics — not address discovery.
Yes — a free MX record lookup with no signup and no account. Query as many domains as you need. It is an MX record lookup tool free of caching too: every MX record lookup resolves live against authoritative nameservers.
Lower is tried first. Equal numbers are load-balanced between hosts. Our free MX record checker that shows only the first host hides the failover path, which is exactly where mail goes when the primary server is unavailable.
The domain cannot receive mail through the normal path. Either it was never configured or the records were removed during a migration. Publish MX records first — this MX record lookup cannot find what was never created.
A single MX record pointing at a dot, meaning the domain accepts no mail at all. It is correct configuration for website-only domains and it stops senders wasting delivery attempts. This MX lookup reports it as its own finding rather than as an empty result.
TTL. Old records keep being served from caches until it expires, and a half-finished migration leaves them in place permanently. Re-run this MX record lookup after propagation, and lower TTLs a day before any planned cutover.
It means the domain can receive mail. Whether a specific mailbox exists, and whether your message passes authentication and reputation checks, are separate questions. An MX record lookup is a precondition check rather than a delivery prediction, and an MX record lookup tool free of that caveat would be overselling.
An MX record lookup tool free of signup and caching. Our MX record lookup resolves every host with priorities, catches Null MX, and identifies the provider.
Free MX record lookup, no signup · MX lookup, live nameservers · Priorities and Null MX flagged · MX lookup, no account
