Free tool
Email header analyzer
Paste the headers of a message and read what the servers wrote down: SPF, DKIM and DMARC results, whether the signature aligns with the From domain, the path the message took, where it waited, and how it threads. Your headers never leave your browser.
Analyze headers
Runs in your browser
Paste the whole message or just the header block. Parsing stops at the first blank line.
FAQ
Questions about email headers
What are email headers?
The lines at the top of every message that record who sent it, who it was for, and what happened on the way: one Received line per server it passed through, the receiving server's SPF, DKIM and DMARC results, and the IDs that tie a reply to the message it answers. Mail clients hide them; the raw message has them all.
How do I read the Received headers?
Bottom to top. Each server adds its Received line above the ones already there, so the lowest is the first hop and the top one is your own mail server. The analyzer puts them in order, oldest first, and shows the delay between each pair.
Why does my message say DMARC passed when SPF failed?
DMARC needs only one of SPF or DKIM to pass and align with the From domain. A message relayed through a forwarder or a mailing list often fails SPF, because the forwarding server is not in the sender's record, while its DKIM signature survives and carries DMARC.
What does DKIM alignment mean?
The domain in the signature's d= tag matches the domain in the From address. Relaxed alignment accepts the same organizational domain (mail.example.com signing for example.com); strict alignment needs the exact domain. A valid signature from an unrelated domain proves nothing about the From line.
Does this tool verify DKIM signatures itself?
No. It reads the Authentication-Results header the receiving server wrote, which is the verdict that server acted on. Verifying a signature again would need the message body and a DNS lookup, and this page makes no network requests.
Are my headers uploaded anywhere?
No. Parsing runs in this page in your browser. Nothing you paste or drop is sent to SendRaven or anyone else, and nothing is stored after you close the tab.
Next step
Replies that arrive as threads, with the authentication already read
SendRaven is email infrastructure for AI agents. Inbound mail comes back parsed, joined to the message it answers on Message-ID, and flagged with sender_authenticated.