Email Header Analyzer

Paste raw email headers to see the Received-hop timeline, SPF/DKIM/DMARC verdicts, and sender-alignment/look-alike checks — parsed entirely in your browser.

What runs where: parsing the headers you paste — every field, the hop timeline, alignment, and anomaly checks below — happens entirely in your browser. Nothing is sent anywhere for that. Three deeper checks are available further down and each makes its own clearly-labeled request to our server, only when you click its button.
What this doesn't do: no spam-score/reputation scoring (that needs a paid API or stateful service this Worker can't run) and no shareable result links — nothing you paste is ever stored server-side, unlike most header analyzers. Refresh the page and it's gone.