Best free DNS and email deliverability checkers

AdminKit is built by Netbase JSC. AdminKit is listed below; the other tools are independent.

Criteria and how we weighted them

This roundup ranks eight tools against five published criteria, in priority order:

1. Free access, no account for at least one SPF, DKIM or DMARC check — a tool that fails this outright is still listed if it’s well known, but ranks behind every tool that passes.
2. Breadth of checks covered in one toolset: SPF, DKIM, DMARC, MX/general DNS, and blacklist, not just one of them.
3. DNS-based blacklist (DNSBL) coverage specifically, since it’s the single feature most requested alongside SPF/DKIM/DMARC checking.
4. Reporting or monitoring over time, for teams past a one-off check (aggregate-report analysis, scheduled rechecks).
5. API or automation access, for teams wiring a check into their own pipeline.

Ranking from those criteria, not from preference, is why AdminKit is third rather than first: AdminKit fails criterion 3 outright today (no blacklist check live) and is weak on criterion 5 (no public API live), while MxToolbox and DNSChecker both have a live blacklist check and MxToolbox additionally has a paid monitoring product and a public API. The table below shows the same facts by feature; the list underneath explains each tool’s placement.

The ranked list, explained

1. MxToolbox — the broadest single option on these criteria. Per MxToolbox’s own blacklist page, read 2026-10-26, it checks a domain or IP against “100+” (105, by its own count) DNS-based blacklists, built up since the company’s 2004 founding (footer copyright: ”© Copyright 2004-2026, MXToolBox, Inc.”). Its SPF, DMARC and DKIM tools are free with no stated account requirement, and its homepage links to both an API product and a “Delivery Center” monitoring product. MxToolbox leads on four of the five criteria; it does not offer one combined multi-signal report page the way AdminKit or DNSChecker’s Email Verifier do.

2. DNSChecker — close behind, and arguably the most feature-dense free option here. Based on dnschecker.org’s own indexed pages, read 2026-10-26 (see the transparency note below), it has dedicated free SPF, DKIM and DMARC checkers, a live IP/domain/email blacklist checker, an Email Verifier that checks six signals (SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI) in one pass, and DNS propagation checking across a stated 100+ global server locations — all with no login required. What its own pages don’t state is a specific DNSBL list count (unlike MxToolbox’s “105+”) or any paid monitoring/API product, which is why it sits behind MxToolbox rather than ahead of it.

3. AdminKit — free, no account, and the only tool here besides DNSChecker’s Email Verifier with a combined report: AdminKit’s SPF check, DMARC check and DKIM check run alongside AdminKit’s DNS, MX, WHOIS and reverse-DNS tools on one site. AdminKit is behind MxToolbox and DNSChecker specifically because its blacklist check and its DNS resolver/leak test are both coming with the AdminKit Check API, not live today, and AdminKit has no public API or paid monitoring product yet either — two of the five criteria this page uses.

4. EasyDMARC — per easydmarc.com, read 2026-10-26, a broad free toolset: DMARC Record Checker and Generator, a DMARC XML Report Analyzer with GeoMaps, SPF and DKIM checkers and generators, BIMI tools, a Domain Scanner and a general DNS Record Checker, with no account stated as required for a single check (its 14-day free trial is for the paid platform). No blacklist check was found on its own pages, which, along with no general MX-lookup tool specifically named, keeps it behind the top three.

5. dmarcian — the DMARC standard’s co-creator, and per dmarcian.com and its SPF Surveyor page, read 2026-10-26, it offers free SPF Surveyor, DMARC Inspector, DMARC Record Wizard, DKIM Inspector and Validator, and BIMI tools, plus a paid DMARC Management Platform with a 30-day trial and professional deployment services. It’s narrower than EasyDMARC on general DNS/MX tooling and has no blacklist check, which is why it ranks just behind EasyDMARC on breadth despite a comparable, well-regarded DMARC-specific toolset.

6. mail-tester — per its own SPF & DKIM Checker and DMARC Checker pages, read 2026-10-26, both are free, read records directly from a domain without requiring a test email to be sent, and the site links to its own API documentation. But mail-tester’s headline product is a spam-score report generated by sending an actual email to a disposable test address — a different job (testing one real message) from the other seven tools’ job (reading DNS records for any domain on demand), which is why it ranks here rather than with the dedicated record-checkers above it.

7. Google Admin Toolbox — per toolbox.googleapps.com, read 2026-10-26, Google’s own free, unauthenticated admin utility belt includes Dig (a web equivalent of the Unix dig command) and Check MX, which per its own page validates “MX and SPF Records” — useful, but with no dedicated DKIM or DMARC checker found on Google’s own pages, no blacklist check, and no monitoring or API product (it’s a diagnostic utility, not a vendor product). That narrower scope places it behind every dedicated SPF/DKIM/DMARC checker in this roundup.

8. intoDNS — per intodns.com, read 2026-10-26, it “checks the health and configuration and provides DNS report and mail servers report,” covering DNS delegation, nameserver health, SOA, MX and A records. Its own report output does not check SPF or DMARC records at all, which is the single biggest reason it’s included here for completeness (it’s a well-known free DNS/mail-health tool) rather than ranked alongside the SPF/DKIM/DMARC-focused tools above it.

A transparency note on DNSChecker

Every automated fetch of dnschecker.org’s own pages for this comparison returned an HTTP 403 (blocked) at verification time (2026-10-26). Rather than drop a well-known, relevant tool from the roundup or guess at its feature set, the facts cited above come from that domain’s own publicly indexed page titles, descriptions and specific tool-page URLs — each one linked directly above so it can be checked by visiting dnschecker.org itself. This is the same honest-when-blocked approach AdminKit’s comparison with ipinfo.io and whatismyipaddress.com uses when a direct fetch fails.

Best for your specific need

• A quick one-off SPF/DKIM/DMARC check, no account: AdminKit or DNSChecker — both run all three checks free, with no sign-up.
• Bulk blacklist monitoring across many DNSBLs: MxToolbox, for its sourced “105+” list count and years of accumulated DNSBL relationships.
• An ongoing DMARC rollout with aggregate-report analysis: dmarcian or EasyDMARC, both of which sell a dedicated platform for exactly this, beyond the free one-off checkers.
• Wiring a check into your own pipeline: MxToolbox or mail-tester, the two tools here with a documented API product.
• Testing how a real outgoing email will be treated by spam filters: mail-tester — the only tool in this roundup built around sending an actual test message.
• A quick lookup from inside Google Workspace admin tooling: Google Admin Toolbox’s Dig or Check MX.
• A general DNS delegation and mail-server health audit, not SPF/DMARC specifically: intoDNS.

Where AdminKit is honestly behind

AdminKit does not match MxToolbox’s or DNSChecker’s blacklist coverage today — the blacklist check is coming with the AdminKit Check API, not live — and AdminKit has no public API or paid monitoring product to compare against MxToolbox’s Delivery Center, EasyDMARC’s or dmarcian’s rollout platforms. What AdminKit does offer today is a free, no-account combined report across SPF, DKIM, DMARC, MX, DNS and WHOIS on one page, which is why it ranks third rather than last — ahead of tools that are narrower (Google Admin Toolbox), differently scoped (mail-tester, intoDNS), or that gate ongoing use behind a paid platform (EasyDMARC, dmarcian) sooner than AdminKit’s checks do.

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Trademarks belong to their respective owners; AdminKit is not affiliated with MxToolbox, Inc., DNSChecker, EasyDMARC, dmarcian, Google, intoDNS or mail-tester.