Email header analyser
Paste the raw headers of an email to see its delivery path, the delay at each hop, SPF/DKIM/DMARC verdicts and spoofing red flags. Runs entirely in your browser.
What the headers tell you
Every server that handles a message adds a Received line at the top, so reading them from the bottom up gives the delivery path. The analyser puts the hops in order, shows the delay between each, and highlights the slowest one.
It also reads Authentication-Results to show whether SPF, DKIM and DMARC passed at the receiving server, and flags signs of spoofing: a Reply-To that differs from From, a display name that impersonates another address, or a From domain that failed authentication.
How to copy the headers
- Gmail: open the message, ⋮ menu, "Show original".
- Outlook on the web: open the message, … menu, "View", "View message details".
- Apple Mail: View, Message, "All Headers" (or Raw Source).
- Thunderbird: View, "Message Source".
Questions
- Is it safe to paste headers here?
- Yes. The analysis runs entirely in your browser and nothing is sent to MtrXTools or anyone else. Headers can contain internal hostnames and addresses, so avoid pasting them into tools that upload them.
- Why was my message delayed?
- Look for the hop with the biggest delay. A long gap at the first hop usually means the sending client or a queue held it; a gap at a filtering service means it was scanned or greylisted.