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Header analyzer

/headers

Paste raw headers to trace a message's route and its authentication results.

Everything is parsed in your browser. Nothing is uploaded or stored.

What email headers tell you

  1. What it is

    Every message carries a hidden trail: each server it passed through, and the authentication verdict at each step.

  2. Why it matters

    Reading that trail shows exactly where a message slowed down, and whether it was authenticated on arrival.

  3. Without it

    Without reading headers, a delivery problem is guesswork — you can only see that mail was late or missing.

What we show

  • SPF, DKIM and DMARC results from the Authentication-Results header
  • Every Received hop, in the order the message travelled
  • The delay introduced at each hop, so you can spot slow relays
  • Key fields: From, To, Subject and Message-ID

Common questions

Where do I find raw headers?

In Gmail, open a message → the three-dot menu → "Show original". In Outlook, open the message → File → Properties → Internet headers. Paste the whole block.

Is my email data safe?

Yes. Parsing happens entirely in your browser — the headers never leave your device.