Best free DKIM record checkers

AdminKit is built by Netbase JSC. AdminKit is listed below; MxToolbox, DNSChecker, EasyDMARC, dmarcian and mail-tester are independent and not affiliated with AdminKit.

What each tool’s own page confirms

MxToolbox’s DKIM record check, read 2026-11-04, “will perform a DKIM record test against a domain name and selector for a valid published DKIM key record.” Its form accepts either a combined domain:selector value, or the full selector hostname entered in the Domain field with the Selector field left empty — two input shortcuts, but a selector is still required either way. No pricing or account requirement is stated on the page.

DNSChecker is a well-known free DNS tool site; AdminKit’s existing best free SPF and DMARC checkers roundup already sources a dedicated free DKIM checker from the site’s own indexed pages (confirmed 2026-10-26). A direct automated fetch of this specific page returned an HTTP 403 (blocked) at verification time for this page (2026-11-04) — see the transparency note below.

EasyDMARC’s DKIM Lookup Tool, read 2026-11-04, “simplifies the DKIM record-checking process by locating your domain’s DKIM record and validating its accuracy.” Its form asks for a domain and selector, but also offers a “Detect all selectors” option that tries to find a domain’s selector automatically rather than requiring you to already know it — a genuine step beyond the other tools in this roundup, none of which states an equivalent auto-detect feature.

dmarcian’s DKIM Inspector, read 2026-11-04, “helps verify that the public key portion of the DKIM signature has been published correctly.” It’s listed under dmarcian’s free DMARC Tools, requires both an “Enter domain” and “Enter selector” field, is free with no account required, and its own page states: “We respect your privacy. We won’t store the information you enter in this tool or use it for sales or marketing purposes.”

mail-tester’s SPF & DKIM Checker, read 2026-11-04, reads: “Check if your domain has these 2 email signatures set up and valid,” with separate “Domain name” and “DKIM Selector” input fields. It’s listed under mail-tester’s free tools, with no account requirement stated for using the checker itself.

AdminKit’s DKIM check asks for a domain and selector, fetches the TXT record at <selector>._domainkey.<domain>, and validates its syntax and public key with AdminKit’s own code, explaining the p=, k= and t= tags registered in IANA’s DKIM-Signature Tag Specifications. It’s free, requires no account, and — like MxToolbox, dmarcian and mail-tester — asks you to already know the selector rather than detecting it automatically the way EasyDMARC’s tool does; instead, AdminKit’s tool page explains common selector-hint patterns by provider to help you find it.

A transparency note on DNSChecker

A direct automated fetch of dnschecker.org’s DKIM checker page returned an HTTP 403 (blocked) at verification time (2026-11-04), 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 form fields, this page reuses the fact already sourced elsewhere on AdminKit from the domain’s own indexed pages (confirmed 2026-10-26: DNSChecker has a dedicated free DKIM checker alongside its SPF, DMARC and blacklist checkers) and marks anything not independently re-verified today — such as whether a selector field is required or optional — as unverified (dash) rather than inventing it.

The honest angle

Every tool in this roundup runs a free DKIM lookup with no account required. The real differences are at the edges: EasyDMARC’s own page is the only one here offering to detect a domain’s selectors automatically, which matters because RFC 6376 defines no DNS record listing a domain’s active selectors (§3.1) — everyone else, including AdminKit, asks you to supply it. MxToolbox, EasyDMARC and dmarcian all sell a paid platform for ongoing DMARC/DKIM management behind their free checkers; AdminKit and mail-tester don’t today. AdminKit’s DKIM check sits alongside AdminKit’s own SPF and DMARC checks on one site, the same bundling pattern MxToolbox, DNSChecker, EasyDMARC, dmarcian and mail-tester each offer in their own way — see DKIM selector and record mistakes that break signing for what an empty key, wrong selector or missing record each actually mean, and the glossary entries for DKIM and DKIM selector for the underlying terms.

For the mail-routing record checked upstream of DKIM, see best free MX record lookup tools; for how all three authentication records fit together, see SPF, DKIM and DMARC explained.

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