Best free MX record lookup tools
AdminKit's MX lookup resolves a domain's mail-exchanger records in priority order, then resolves each host's A/AAAA record so you can see which can actually receive mail; MxToolbox's MX Lookup Tool runs the same priority-ordered lookup plus live SMTP and blacklist diagnostics, while DNSChecker, Google Admin Toolbox and intoDNS run a broadly similar MX check, per their own pages.
AdminKit is built by Netbase JSC. AdminKit is listed below; MxToolbox, DNSChecker, Google Admin Toolbox and intoDNS are independent and not affiliated with AdminKit.
What each tool’s own page confirms
MxToolbox’s MX Lookup Tool, read 2026-11-04, states plainly: “This test will list MX records for a domain in priority order. The MX lookup is done directly against the domain’s authoritative name server, so changes to MX Records should show up instantly.” The same page goes well beyond a plain MX lookup, offering diagnostics to connect to the listed mail servers directly, verify reverse DNS, run an Open Relay check, measure response times, and check the server’s IP “against 105 DNS based blacklists” — a bundled mail-diagnostics suite, not just a record reader. No pricing or account requirement is stated on the page itself.
DNSChecker is a well-known free DNS tool site, and AdminKit’s existing DNSChecker vs MxToolbox comparison already sources its SPF, DKIM, DMARC and blacklist checkers from the site’s own indexed pages. A direct automated fetch of its MX lookup page returned an HTTP 403 (blocked) at verification time for this page (2026-11-04) — see the transparency note below for why this page states only that the tool exists at that URL rather than guessing at its result layout.
Google Admin Toolbox’s Check MX, read 2026-11-04, is a free, unauthenticated tool whose own page states it will “Check MX and SPF Records” for a domain — a quick two-signal check, with no dedicated DKIM or DMARC checker, blacklist check, or bundled SMTP diagnostics found on Google’s own pages.
intoDNS, read 2026-11-04, states on its own homepage: “IntoDNS checks the health and configuration and provides DNS report and mail servers report,” covering DNS delegation, nameserver health, SOA, MX and A records together as one general audit. It has no standalone, dedicated MX-only lookup the way the other three tools here do — MX records are one part of a much broader report.
AdminKit’s MX lookup queries the same DNS-over-HTTPS proxy as the general DNS lookup tool, filtered to the MX type defined in RFC 1035 (§3.3.9), then makes a second round of A/AAAA lookups for up to 5 of the listed mail hosts so you can see at a glance whether a correctly listed host can actually receive mail. It is free, requires no account, and does not bundle a live SMTP connectivity test, reverse-DNS check or blacklist check into the same lookup — those live separately as AdminKit’s SPF, DMARC and DKIM checks today, with a blacklist check coming with the AdminKit Check API.
A transparency note on DNSChecker
A direct automated fetch of dnschecker.org’s MX lookup page returned an HTTP 403 (blocked) at verification time (2026-11-04) for this specific page, the same block AdminKit’s other DNSChecker comparisons have documented. Rather than drop a well-known, relevant tool from this roundup or guess at its result layout, this page states only what is already independently sourced elsewhere on AdminKit (DNSChecker’s known free SPF/DKIM/DMARC/blacklist tool catalog) and otherwise marks DNSChecker’s MX-specific row cells unverified (dash) rather than inventing a feature it may or may not have.
The honest angle
If you want a single MX lookup bundled with live SMTP connectivity, reverse-DNS and blacklist diagnostics, MxToolbox’s own page offers the most in one tool. If you want a quick MX+SPF read without leaving Google Workspace admin tooling, Google Admin Toolbox’s Check MX does that and nothing more. If you’re auditing a domain’s overall DNS and mail-server health rather than just its MX records, intoDNS’s combined report covers more ground than a dedicated MX lookup. AdminKit’s MX lookup sits between these: a dedicated, free, no-account MX lookup that also confirms each host actually resolves, without folding in a live SMTP test or blacklist check — see what MX record priority actually does and the glossary entry for MX record for what the priority column and a missing record each actually mean.
For the matching email-authentication check once mail is routed to the right host, see best free DKIM record checkers and SPF, DKIM and DMARC explained.
Trademarks belong to their respective owners; AdminKit is not affiliated with MxToolbox, Inc., DNSChecker, Google, or the operators of intoDNS.
| Feature | AdminKit | MxToolbox | DNSChecker | Google Admin Toolbox | intoDNS |
|---|---|---|---|---|---|
| Free, standalone MX record lookup you can run directly on the page, no account required | ✓ | ✓ | ✓ | ✓ | MX shown inside a general mail-servers report, not a standalone MX tool (own page) |
| Shows each MX record's priority/preference value | ✓ | ✓ | — | — | — |
| Also resolves whether each listed mail host's own A/AAAA record exists | ✓ | — | — | — | — |
| Bundles further mail/network diagnostics (live SMTP connect, reverse DNS, open relay, blacklist check) on the same page | ✗ | ✓ | — | — | ✓ |
| Also validates SPF, DMARC or DKIM records in the same toolset (elsewhere on the same site) | ✓ | ✓ | Separate SPF/DKIM/DMARC checkers on the same site (own indexed pages) | ✗ | ✗ |
AdminKit vs MxToolbox
Free, standalone MX record lookup you can run directly on the page, no account required
Shows each MX record's priority/preference value
Also resolves whether each listed mail host's own A/AAAA record exists
Bundles further mail/network diagnostics (live SMTP connect, reverse DNS, open relay, blacklist check) on the same page
Also validates SPF, DMARC or DKIM records in the same toolset (elsewhere on the same site)
AdminKit vs DNSChecker
Free, standalone MX record lookup you can run directly on the page, no account required
Shows each MX record's priority/preference value
Also resolves whether each listed mail host's own A/AAAA record exists
Bundles further mail/network diagnostics (live SMTP connect, reverse DNS, open relay, blacklist check) on the same page
Also validates SPF, DMARC or DKIM records in the same toolset (elsewhere on the same site)
AdminKit vs Google Admin Toolbox
Free, standalone MX record lookup you can run directly on the page, no account required
Shows each MX record's priority/preference value
Also resolves whether each listed mail host's own A/AAAA record exists
Bundles further mail/network diagnostics (live SMTP connect, reverse DNS, open relay, blacklist check) on the same page
Also validates SPF, DMARC or DKIM records in the same toolset (elsewhere on the same site)
AdminKit vs intoDNS
Free, standalone MX record lookup you can run directly on the page, no account required
Shows each MX record's priority/preference value
Also resolves whether each listed mail host's own A/AAAA record exists
Bundles further mail/network diagnostics (live SMTP connect, reverse DNS, open relay, blacklist check) on the same page
Also validates SPF, DMARC or DKIM records in the same toolset (elsewhere on the same site)
Frequently asked questions
Is this page ranking MxToolbox, DNSChecker, Google Admin Toolbox and intoDNS from best to worst?
No. A standalone MX-only lookup, the same lookup bundled with live SMTP/blacklist diagnostics, a quick MX+SPF utility, and MX records folded into a much wider general DNS/mail-health report solve different problems, so a single best-to-worst order would misrepresent what each is for. The table below states only what each tool's own page confirms, so you can match the tool to what you actually need.
Does AdminKit's MX lookup also confirm the mail host actually accepts mail?
No. AdminKit's MX lookup resolves each listed mail host's A/AAAA record, which confirms the hostname exists in DNS, not that it accepts a live SMTP connection on port 25 — that needs an actual SMTP test, which this tool does not make. See [how to read an MX lookup result](/guides/how-to-read-an-mx-lookup-result/) for what the priority and host-resolution columns do and don't confirm.
Why does this page describe some of DNSChecker's MX lookup facts as based on indexed pages rather than a direct read?
A direct automated fetch of dnschecker.org/mx-lookup.php returned an HTTP 403 (blocked) at verification time (2026-11-04). Rather than drop a well-known, relevant tool from the roundup or guess at its feature set, this page states only that the page exists at that URL and is part of DNSChecker's known free tool catalog (already sourced elsewhere on AdminKit, e.g. [DNSChecker vs MxToolbox](/compare/dnschecker-vs-mxtoolbox/)), and leaves unverified specifics about its result layout out of the table entirely.
Does intoDNS have a dedicated, standalone MX lookup tool like the others in this roundup?
No. intoDNS's own homepage states it "checks the health and configuration and provides DNS report and mail servers report" — MX records appear inside that general mail-servers report, not as a dedicated, standalone MX-only lookup the way AdminKit, MxToolbox, DNSChecker and Google Admin Toolbox's Check MX each offer. It's included here for completeness as a well-known free DNS/mail-health tool, not as a peer standalone MX lookup.
Does this page use MxToolbox's, DNSChecker's, Google's or intoDNS's logo or brand assets?
No. All four names are used only to identify and compare publicly available services (nominative use). AdminKit is not affiliated with or endorsed by MxToolbox, Inc., DNSChecker, Google, or the operators of intoDNS.
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