Header analyzer
Email header analyzer
Every email carries a hidden record of where it came from and what the receiving server thought of it. Paste the full headers of a message and we turn them into plain answers: did it pass SPF, DKIM and DMARC, who really sent it, and where it was held up. It runs in your browser, so nothing you paste is sent anywhere.
This tool runs entirely in your browser. Nothing you paste is sent to us or to anyone else, and nothing is stored.
How it works
What this checks
- Authentication results SPF, DKIM, DMARC and ARC results from the receiving server’s Authentication-Results header, and Microsoft’s combined verdict when present.
- Sender alignment Whether From matches the Return-Path, the DKIM signature and Reply-To, and tricks like an address hidden in the display name.
- Every hop and delay Each server the message passed through, oldest first, with the time between steps and any delay over five minutes.
- Message-ID domain The domain in the Message-ID, a quick clue to the system that created the message.
- Spam filter verdicts SpamAssassin style scores and Microsoft’s spam and bulk levels, when present.