Email header analyzer
Paste raw email headers to trace the delivery path hop by hop, spot where a message was delayed, and check SPF, DKIM, and DMARC authentication.
- 100% in your browser — never uploaded
- Works with full raw emails too
- Free, no signup
Before you paste
How to get the raw headers
Gmail
Open the message → ⋮ menu (top right) → “Show original” → copy everything.
Outlook (desktop)
Open the message → File → Properties → copy the “Internet headers” box.
Outlook (web)
Open the message → ⋯ → View → “View message details”.
Apple Mail
Open the message → View → Message → All Headers (or Raw Source).
Thunderbird
Open the message → More → “View Source” → copy the top block.
Yahoo Mail
Open the message → ⋯ → “View raw message”.
FAQ
Are my email headers uploaded anywhere?
No. The analysis runs entirely in your browser with JavaScript — nothing you paste here is sent to our servers. You can disconnect from the internet after the page loads and it still works.
How do I read the Received chain?
Each mail server that handles a message stamps a Received header on top, so the raw headers read newest-first. This tool reverses them into chronological order: the first hop is the sender's server, the last is your mailbox provider, and the delay column shows how long each server took to pass the message on.
What are SPF, DKIM, and DMARC?
Three sender-authentication checks your mail provider runs on arrival. SPF verifies the sending server is allowed to send for the domain, DKIM verifies a cryptographic signature over the message, and DMARC checks that at least one of those aligns with the visible From domain and says what to do if not. “pass” on all three means the sender is who they claim to be.
Does a failed SPF or DKIM check mean the email is fake?
Not always — forwarding commonly breaks SPF, and mailing lists can break DKIM. But a DMARC fail on a message that claims to be from your bank is a serious red flag. Combine the checks with the routing path and the Reply-To/Return-Path signals shown above.
Why is there a big delay between two hops?
The receiving server may have greylisted the message (asked the sender to retry), been backlogged, or the sender queued it. Occasional delays are normal; consistent multi-minute delays point at the server after the gap.
Working with a saved .eml file instead? Open it in our free EML viewer to see the rendered message, headers, and attachments.