Free tool

Email header analyzer

Paste the raw headers of an email to see how it authenticated (SPF, DKIM, DMARC), the route it took with per-hop delays, and whether it carries the required unsubscribe header. Everything is parsed in your browser.

How to get the raw headers

• Gmail: open the message → ⋮ menu → Show original → copy all.
• Outlook: open the message → File → Properties → copy the Internet headers.
• Apple Mail: View → Message → All Headers.

If SPF, DKIM or DMARC shows fail, run your sending domain through the checker and fix the records.