ReaperCloud

Email Header Analyzer

Paste the raw headers of a message. Nothing is sent anywhere and nothing is stored.

Everything from the top of the message down to the first blank line. Pasting the whole message works too — the body is ignored.
These describe the domain rather than this message, and need a few requests to the domain's servers, so they add a second or two. Untick to skip them.
How to get raw headers
  • GmailOpen the message → ⋮ menu → Show original → copy everything above the blank line.
  • Outlook (desktop)Open the message in its own window → File → Properties → Internet headers.
  • Outlook on the webOpen the message → ⋯ menu → View → View message details.
  • Apple MailView → Message → All Headers, or ⇧⌘H.
  • ThunderbirdView → Message Source, or ⌘/Ctrl+U.