JPKCom DB

Mail Header Analyzer

Analyze email headers in your browser: parse RFC 5322 headers, visualize the delivery route, check SPF/DKIM/DMARC — your start for manual, examples, tips.

Make email headers readable — without anything leaving your browser

Every email drags along a block of technical headers that most clients keep hidden: where the message came from, which servers it passed through, whether it could prove it wasn't forged, and whether a spam filter flagged it. The Mail Header Analyzer makes exactly that block visible. You paste the raw headers, click Analyze, and the tool breaks them down into four readable views: the key fields at a glance, the delivery route as a timeline, the authentication results, and a searchable table of every header.

The key point: the whole analysis runs client-side, in your browser. No server ever sees your headers — and email headers in particular tend to carry sensitive details: internal server names, IP addresses, recipient addresses, subject lines. That none of it is uploaded is not a side effect here, it's the whole idea.

The tool is built for anyone who needs to get to the bottom of an email: admins and mail operators tracing why a delivery is stalling; developers checking their SPF, DKIM, and DMARC setup against real headers; support and security teams dissecting a suspicious phishing message; and anyone who simply wants to know why a message landed in spam or arrived hours late.

What the Mail Header Analyzer does — at a glance

  • Parse — paste raw headers, upload a .eml or .txt file, or drop one in; Analyze gets you going.
  • Overview — the central fields (From, To, Subject, Date and more) as a compact table, plus an authentication summary.
  • Route — the delivery path from the Received headers as a timeline from sender to recipient, including waiting times, TLS status, and total transit time.
  • Security — SPF, DKIM, and DMARC as result cards, plus a spam analysis built from the X-Spam-* headers.
  • All Headers — every single header in a searchable table, with copy and download functions.

Architecture: 100% in the browser, no backend

The Mail Header Analyzer has no server component. Parsing, route computation, authentication evaluation, and rendering all happen entirely in JavaScript in your browser. There is no API, no upload endpoint, no server-side caching. Even the file upload and drag-and-drop read the file locally through the browser's FileReader API — the file is never sent anywhere.

Because email headers can contain personal and confidential data, that's a real privacy advantage over many online header analyzers that ship your headers to a third-party server. One caveat: analyzed headers are stored in a local history within the tool (in your browser) so you can restore them after a reload — that, too, never leaves your machine. Details are in the manual.

Try it now

→ Open the Mail Header Analyzer — paste headers, click Analyze, done. No account, free, right in the browser. If you don't have a real email handy, the Example button loads a realistic sample header to play with.

  • DNS, SSL, Redirect & URL — check the DNS records behind SPF, DKIM, and DMARC once the analyzer points to a problem.
  • IP tools — look up and place a sender or relay IP pulled from the Received lines.
  • Hash generator — compute checksums, for instance to compare a downloaded header file against the original.

There's more on the sub-pages: the manual with every tab and parsing rule, real-world examples, and collected tips & tricks.