DNSChecker vs MxToolbox: which is better for diagnosing email and DNS problems?
Neither tool clearly wins for diagnosing email and DNS problems: MxToolbox checks a domain or IP against 105+ DNS-based blacklists (mxtoolbox.com/blacklists.aspx, read 2026-10-26), while DNSChecker checks DNS propagation across 100+ global server locations and runs a six-signal Email Verifier (dnschecker.org, read 2026-10-26) — pick MxToolbox for blacklist depth and its monitoring/API product, DNSChecker for propagation checks and a combined auth-signal report, and AdminKit's free SPF, DKIM, DMARC and MX checks fit alongside either today.
AdminKit is built by Netbase JSC. AdminKit is listed below; DNSChecker and MxToolbox are independent.
What each tool actually is
DNSChecker and MxToolbox overlap more than most pairs of DNS tools: based on dnschecker.org’s own indexed pages, read 2026-10-26 (see the transparency note below), DNSChecker has dedicated free SPF, DKIM and DMARC checkers and a live IP/domain/email blacklist checker, the same core set MxToolbox is best known for. Per MxToolbox’s own blacklist page, read 2026-10-26, it checks “100+” (105, by its own count) DNS-based blacklists, and its SPF, DMARC and DKIM tools are free with no stated account requirement, backed by a company operating, per its footer copyright notice, since 2004.
The difference shows up at the edges. DNSChecker’s own pages lean into DNS propagation: a stated 100+ global server locations for checking how a DNS change has spread, plus an Email Verifier that checks six authentication signals (SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI) together. MxToolbox’s own pages don’t describe a comparable multi-location propagation tool, but do link to a paid “Delivery Center” monitoring product and a public API from its homepage — neither of which DNSChecker’s own pages mention.
Side by side
The table above lines up both tools against the same six features. Neither tool wins every row: DNSChecker’s own pages show a DNSBL checker and global propagation checking with no stated monitoring/API product, while MxToolbox’s own pages show a specific, larger DNSBL count, a longer stated operating history, and a monitoring/API product DNSChecker’s pages don’t mention.
Where AdminKit fits
AdminKit’s SPF check, DMARC check and DKIM check match the core free, no-account checks both DNSChecker and MxToolbox offer, combined on one page with AdminKit’s MX lookup, DNS and WHOIS tools. AdminKit does not have a DNS propagation checker like DNSChecker’s, and its blacklist check is coming with the AdminKit Check API rather than live today — so for blacklist screening or multi-location propagation specifically, DNSChecker and MxToolbox are both more complete right now. AdminKit also has no paid monitoring product or public API yet, unlike MxToolbox.
Best for your specific need
- Checking how a DNS change has propagated globally after a migration: DNSChecker, for its stated 100+ global server locations.
- The widest sourced DNSBL blacklist coverage, with a specific list count: MxToolbox, at “105+” lists per its own page.
- A single free report covering SPF, DKIM, DMARC and more authentication signals in one pass: DNSChecker’s Email Verifier, or AdminKit’s combined SPF/DKIM/DMARC/DNS/MX/WHOIS report.
- Ongoing monitoring with a vendor-provided dashboard or API: MxToolbox, for its stated Delivery Center and API products.
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). The facts above about DNSChecker’s SPF, DKIM, DMARC, blacklist, Email Verifier and propagation tools 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, in keeping with the rule that every claim about a competitor here must trace back to that competitor’s own page.
Trademarks belong to their respective owners; AdminKit is not affiliated with DNSChecker or MxToolbox, Inc.
| Feature | AdminKit | DNSChecker | MxToolbox |
|---|---|---|---|
| Dedicated free SPF, DKIM and DMARC checkers, no account required | ✓ | ✓ | ✓ |
| DNS-based blacklist (DNSBL) / IP blacklist check | Coming with the API | ✓ | 105+ lists (own page) |
| DNS propagation check across many global server locations | — | 100+ global servers (own page) | — |
| Combined multi-signal email-auth report in one pass | SPF+DKIM+DMARC+DNS+IP in one page | Email Verifier: 6 signals (own page) | — |
| Paid monitoring platform or public API | Coming with the API | Not publicly listed | Delivery Center + API (own page) |
| Years operating (own stated history) | Launched 2026 | Not publicly listed | Since 2004 (own copyright notice) |
AdminKit vs DNSChecker
DNS-based blacklist (DNSBL) / IP blacklist check
DNS propagation check across many global server locations
Combined multi-signal email-auth report in one pass
Paid monitoring platform or public API
Years operating (own stated history)
AdminKit vs MxToolbox
DNS-based blacklist (DNSBL) / IP blacklist check
Combined multi-signal email-auth report in one pass
Paid monitoring platform or public API
Years operating (own stated history)
Last checked
Sources: DNSChecker — homepage, DNSChecker — SPF checker, DNSChecker — DKIM checker, DNSChecker — DMARC checker, DNSChecker — IP blacklist checker, DNSChecker — Email Verifier, DNSChecker — MX lookup, MxToolbox — homepage, MxToolbox — Blacklist check, MxToolbox — SPF record check, MxToolbox — DMARC record check, MxToolbox — DKIM record check
Frequently asked questions
Which is better overall, DNSChecker or MxToolbox?
They're close on the checks most people need (SPF, DKIM, DMARC and blacklist are all free and live on both), so "better" depends on the job. MxToolbox's own blacklist page states a specific DNSBL count (105+) and its homepage links to a paid monitoring product and an API; DNSChecker's own pages emphasize DNS propagation checking across a stated 100+ global server locations and a six-signal Email Verifier, with no DNSBL count or monitoring product stated. Neither page claims to beat the other across the board, and neither should this page.
Does DNSChecker check DKIM records, not just SPF and DMARC?
Yes. Per DNSChecker's own DKIM Checker page, it has a dedicated DKIM lookup tool that takes a domain and DKIM selector and shows whether a DKIM record is configured — alongside its separate SPF and DMARC checkers and its Email Verifier, which checks SPF, DKIM, DMARC, MTA-STS, TLS-RPT and BIMI together.
Does AdminKit do DNS propagation checking like DNSChecker?
No, not today. AdminKit's DNS resolver/leak test — which shows which resolver your own connection uses, a related but different check from DNSChecker's multi-location propagation lookup for a domain — is coming with the AdminKit API, not live. AdminKit does not offer a global multi-location propagation checker and has no current plan described for one.
Why does this page describe some DNSChecker facts as based on indexed page content rather than a direct fetch?
Every automated attempt to fetch dnschecker.org's own pages for this comparison returned an HTTP 403 (blocked) at verification time (2026-10-26). Rather than guess at its feature set or drop it from a comparison buyers are actively searching for, the facts here are drawn from dnschecker.org's own publicly indexed page titles, descriptions and specific tool-page URLs, each linked so it can be verified directly by visiting the page.
Does this page use DNSChecker's or MxToolbox's logo or brand assets?
No. Both names are used only to identify and compare publicly available services (nominative use). AdminKit is not affiliated with or endorsed by DNSChecker or MxToolbox, Inc.
Want AdminKit to watch this for you?
Free checks tell you the state today. Protective DNS and monitoring tell you when it changes.