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Email header analyzer

Paste a raw email (headers are enough — body is ignored). The Received chain is parsed into a hop-by-hop trace; SPF, DKIM and DMARC verdicts are surfaced from Authentication-Results, and a live SPF check runs against the source IP. Press ⌘/Ctrl ⏎ to submit.

Tip: in Gmail on desktop, "Show original" → copy the whole thing.
Where do I find the raw headers?

On a computer

  • Gmail (web) — open the message, ⋮ menu → Show original → Copy to clipboard.
  • Outlook / Microsoft 365 (web) — ⋯ menu → View → View message source.
  • Apple Mail (macOS) — View → Message → All Headers (⇧⌘H).
  • Thunderbird — View → Message Source (⌘/Ctrl U).
  • Proton Mail — ⋯ menu → View headers.

On a phone

The Gmail, Outlook and Apple Mail mobile apps have no raw-source view — Show original is desktop-web only. Two ways around it:

  • Use the desktop site in your phone's browser. Open mail.google.com, then request the desktop version — Chrome: ⋮ → Desktop site; Safari: aA → Request Desktop Website. Show original then appears in the ⋮ menu.
  • Forward the message as an attachment to yourself (Gmail app: ⋮ → Forward as attachment), then open the .eml file — it is plain text, and the headers are everything above the first blank line.

Only the headers are needed. Paste them alone if you'd rather not include the body — nothing is stored beyond the snapshot this run creates.