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Deliverability tools

Free, no-signup checks for the DNS records that decide whether your mail authenticates. Checkers run real DNS lookups server-side; generators and the header analyzer run entirely in your browser.

• SPF Checker/spf-checkerLook up a domain's SPF record, count DNS lookups against the 10-lookup limit, and catch permerrors.
• DKIM Checker/dkim-checkerFetch and validate a DKIM key by selector, or probe 16 common selectors.
• DMARC Checker/dmarc-checkerLook up and grade a domain's DMARC policy — reject, quarantine, none, or missing.
• MX Lookup/mx-lookupList a domain's mail servers in priority order and verify each one resolves.
• SPF Generator/spf-generatorBuild a valid SPF record from your sending sources — runs in your browser.
• DMARC Generator/dmarc-generatorCreate a DMARC record with staged-rollout guidance from p=none to p=reject.
• Email Authentication Checker/email-authentication-checkerOne summary board: SPF, DKIM, DMARC, MX and BIMI for any domain.
• Email DNS Check/email-dns-checkEvery mail-related DNS record for a domain in one audit: SPF, DKIM, DMARC, MX, PTR, BIMI.
• Blacklist Checker/blacklist-checkerQuery a curated set of free DNSBL zones for an IP or domain, with honest handling of Spamhaus limits.
• Reverse DNS Checker/reverse-dns-checkerPTR lookup with forward-confirmation (FCrDNS) for a sending IP, or a domain's MX hosts.
• BIMI Checker/bimi-checkerValidate a BIMI record, the logo SVG, the VMC, and the DMARC-enforcement prerequisite.
• Email Header Analyzer/email-header-analyzerPaste headers, see the delivery path and auth verdicts — parsed in your browser, nothing sent anywhere.
• Email Deliverability Setup Score/email-deliverability-scoreA 0–100 configuration score over SPF, DKIM, DMARC, MX, reverse DNS and BIMI — a setup audit, not an inbox placement test.
• Deliverability Troubleshooter/deliverability-troubleshooterA guided wizard from symptom to ranked probable causes — runs entirely in your browser, answers never leave it.

Next wave

In development — these need sending infrastructure (outbound SMTP connections), so they ship after that layer exists.

• SMTP TestComing soonConnect to a mail server and verify the handshake, including a TLS/STARTTLS tab.