Tools / Header analyzer · free · runs in your browser

What did the receiving server record about this message?

Paste the raw headers of a message you received. The analyzer reads the result the final receiving server recorded, ties it to the route, and says what it proves and what it doesn't.

Your headers stay in this browser

The analysis runs on this page. What you paste is not sent to our server, not stored and not added to analytics.

Where to find the headers

Gmail: open the message, then Show original. Outlook: View message source.

What it reads

The Received, Authentication-Results, ARC and DKIM-Signature lines, as the servers wrote them.

What it can't tell you

It looks nothing up and verifies no signature itself: it reports what the receiving server recorded, and only when that record can be tied to the route.