Free tool
See what receivers seein your email headers.
Paste the raw headers of any email. We parse the DKIM signatures and verify them against DNS, read the Authentication-Results, trace the mail path, and list every finding with its fix. No account, no API key.
In Gmail: open the message, click the three dots, then "Show original". Copy the full source and paste it above.
What this checks
DKIM, SPF, DMARC and more, from the actual message.
The spam checker reads DNS records. This tool reads the email itself. Paste the raw source and see what receivers saw when they decided whether to deliver it.
- DKIM signaturesEvery signature parsed, verified against the public key in DNS, and checked for key strength.
- Authentication-ResultsWhat the receiving MTA reported for SPF, DKIM and DMARC, extracted from the header.
- DMARC alignmentWhether the signing domain aligns with the From header domain, so DMARC can pass.
- Mail pathEvery Received hop from sender to receiver, with timestamps and protocols.
- Header complianceMessage-ID, Date and List-Unsubscribe. Missing any of these is a negative signal.
How to get your headers
Copy the full message source.
- In Gmail: open the message, click the three dots, then "Show original". Copy everything.
- In Outlook: open the message, click File, then Properties. The headers are in the "Internet headers" box.
- In Apple Mail: open the message, then View, then Message, then All Headers.
- From a Postmark or Mailgun dashboard: find the message in the activity log and copy the raw source.
API
Check your domain too.
The spam checker reads SPF and DMARC records from DNS for any domain. Together, the two tools cover both sides: what the domain publishes, and what the message actually carries.