Free tool · pre-send diagnostic

Email Deliverability Test

Audit your sending domain’s SPF, DMARC, DKIM, MX, and DNSBL blocklist status alongside optional message headers and content signals in a single diagnostic report.

How it works

What the diagnostic checks

We run five checks in one pass: live DNS queries for SPF, DMARC, and your DKIM selector; MX record validation; DNSBL lookups on the primary mail server IPv4; RFC 5322 header analysis when raw headers are pasted; and content/link hygiene rules when a subject or body is supplied.

Limits

Pre-send checks vs. inbox placement

  • Evaluates published SPF, DMARC, DKIM, MX, and DNSBL records over public DNS, plus optional RFC 5322 headers and content rules.
  • Passing authentication, DNS, blocklist, and content checks does not guarantee inbox placement; mailbox providers also weigh sender engagement and internal domain reputation.
  • Unreachable DNS or DNSBL servers are reported as Incomplete or Unchecked rather than assumed clean.
  • Anonymous use is limited to 30 diagnostics per hour.