Paste an email's header and see the route, per-hop delays and SPF, DKIM and DMARC results, all in the browser.
Every email carries a technical header that records where the message went and how it was authenticated. This tool interprets that header: it reconstructs the chain of Received servers in the correct chronological order (origin → destination), computes the time spent at each hop to reveal delivery bottlenecks, and extracts the essential fields (From, To, Delivered-To, Subject, Date, Message-ID, Return-Path, Reply-To). Most importantly, it reads the authentication results (Authentication-Results and Received-SPF) and shows whether SPF, DKIM and DMARC passed or failed. It also flags classic phishing tells, such as the From differing from the Return-Path, the Reply-To pointing to another domain, or a display name that contains a different address than the real one (e.g. showing “[email protected]” <[email protected]>). Because everything runs in the browser, you can analyze suspicious messages without exposing them to third parties.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
<iframe
src="https://jkit.tools/embed/en-US/email-header-analyzer"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="Email Header Analyzer"
></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
In Gmail, open the message, click the three dots (⋮) and choose “Show original”. In Outlook, open the message, go to File › Properties and copy the “Internet headers”. In Apple Mail, use View › Message › All Headers. Paste the whole block here.
Paste the original header (Gmail: ⋮ › “Show original”; Outlook: File › Properties › Internet headers). Folded lines and the blank line before the body are handled automatically.
The tool reconstructs the path the message traveled (Received chain), computes the delay at each hop, extracts the key fields and shows the SPF, DKIM and DMARC results. Nothing leaves your browser.
For safety and privacy, this tool sends nothing anywhere: you paste the header and all analysis, parsing, route and authentication, runs 100% in your browser. No server is used as an intermediary.