Paste the raw headers from any email to trace its delivery path hop by hop, see where time was lost, read the SPF, DKIM and DMARC verdicts the receiving server recorded, and check whether the From domain aligned. Parsed entirely in your browser; nothing is uploaded.
Every server that handles a message stamps a Received header on top of the stack, so the raw headers read newest first. This analyzer reverses them into delivery order, works out the delay at each hop, and picks out the sending server's IP. A single hop holding mail for minutes usually means greylisting or a backed-up queue.
The receiving server records its authentication verdicts in Authentication-Results. Trust only the topmost one: it was added by your own provider. Anything below it is ordinary text that the sender could have written, including a forged "pass".
SPF, DKIM, DMARC and ARC verdicts as the receiver saw them at delivery time.
Whether the SPF domain or a DKIM signing domain matches the From domain, which is what DMARC actually checks.
Each hop from origin to mailbox, oldest first, with the time it spent there.
Signing domain, selector and algorithm, with a link to check each key.
Message-ID, a sane Date, and one-click unsubscribe (List-Unsubscribe plus List-Unsubscribe-Post), which Gmail and Yahoo require.
Alignment. SPF passed for the Return-Path domain, but that is your platform's domain, not your From domain. DKIM-sign as your own domain, or set up a custom return path, and DMARC will pass.
Messages copied from a Sent folder, drafts, and some internal mail never pass through a receiving server's checks. Analyze a copy you received in another mailbox instead.
One of the servers has a wrong clock or time zone. Delays around that hop are unreliable; the rest of the path is still accurate.
No. Parsing happens in your browser and nothing leaves it.
Point an MCP client (Claude, Cursor, any agent) at https://powerline.ai/mcp and call analyze_headers, or hit the JSON endpoint directly. No key, no account.
curl -X POST https://powerline.ai/api/tools/headers \ -H "Content-Type: text/plain" \ --data-binary @headers.txt
Open .eml and .emlx files in the browser: rendered body, headers, authentication and attachments.
Check a sending IP against 18 email DNS blacklists, grouped by how much each one matters.
Find the DKIM public key for a selector (or auto-detect common ones) and check its size and flags.
Read the DMARC policy, alignment and reporting tags, and check that report addresses will accept reports.
See how your HTML email actually renders in real Gmail, Outlook.com and Yahoo Mail accounts. Free screenshots.