Email header analyzer: see what the receiver saw
Paste the headers: we show you the SPF, DKIM and DMARC results, who signed the email and which servers it went through.
- Free, no sign-up
- All in your browser: nothing is sent
- SPF, DKIM, DMARC and route
The analysis runs only in your browser: the headers are not sent anywhere.
Where to find the headers
Open the original email
Gmail: ⋮ › “Show original”. Outlook: File › Properties.
Copy and paste
All the headers, from the first “Received” line on.
Read the result
SPF, DKIM and DMARC as the receiver saw them, and the server route.
In Gmail open the email, ⋮ menu › “Show original” and copy everything. In Outlook: open the email, File › Properties, “Internet headers” box. In Apple Mail: View › Message › All Headers.
The SPF, DKIM and DMARC results are in the Authentication-Results line, written by the server that received the email.
Frequently asked questions
Are the headers sent to MailSenpai?
No: the analysis runs in your browser. Only if you click “Check the DNS records” is the sender’s domain checked.
Why does DKIM show “fail”?
The email was changed after signing, or the published key doesn’t match the one the sending service used.
What does dmarc=fail with SPF and DKIM pass mean?
They pass on a domain different from the From domain: alignment is missing.
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