Email Header Analyzer
Paste the raw headers of an email to see the servers it passed through, where it was delayed, and whether SPF, DKIM and DMARC passed.
Analysed in your browser. The headers are not sent to our server.
How to find the headers
- Gmail: open the message, click the three dots next to Reply, choose Show original, then Copy to clipboard.
- Outlook on the web: open the message, click the three dots, choose View, then View message source.
- Outlook for Windows: open the message in its own window, choose File, Properties, and copy the Internet headers box.
- Apple Mail: select the message, then View, Message, All Headers.
- Thunderbird: open the message and press Ctrl+U (Cmd+U on a Mac).
What headers tell you
Every server that handles an email adds a Received line at the top, so reading them from the bottom up traces the message from sender to inbox. The receiving server also records whether the message passed SPF, DKIM and DMARC in an Authentication-Results line. Together they answer most "why did this go to spam?" and "why was this so slow?" questions.
Reading the results
- Delays. A gap of a few seconds between hops is normal. Minutes usually mean a queue on one server, greylisting, or a spam filter holding the message.
- SPF, DKIM, DMARC. DMARC pass is what matters most. If DMARC fails, check that SPF or DKIM passed for the same domain as the From address.
- From and Return-Path. They often differ when a mailing service sends on your behalf. That is normal, as long as DKIM signs with your domain.
Limitations
- Any server can write anything into the headers below the ones your provider added, so trust the top hops (closest to you) most.
- Times come from each server's clock. A server with the wrong time can make delays look negative or too long.
- We read the results the receiving server recorded. We do not re-check signatures ourselves.