Paste raw email headers and decode the Received chain, SPF/DKIM/DMARC results, hop delays, and sender IP. Nothing is logged.
Email headers are the technical metadata at the top of every message - From, To, Subject, plus a stack of Received lines showing every server the message passed through, plus authentication results (SPF, DKIM, DMARC). Most email clients hide them by default. When something goes wrong with deliverability, the headers are where the answer lives.
This tool parses raw headers and surfaces the key information: who sent it, what path it took, how long each hop took, whether authentication passed, what the originating IP was, and any obvious red flags. No signup, no logging, no storage - paste headers, get analysis, close the tab.
Our complete email authentication guide explains exactly what each result means, the alignment rules that decide DMARC, and how to fix common failures.
Read the SPF/DKIM/DMARC guideEach server records the time it received the message in its own clock. The differences between hops show delivery delay at each step. Most hops are under 1 second; long delays (10+ seconds, minutes, hours) indicate queueing - often because the receiving server was greylisting, throttling, or backlogged.
Two common reasons: (1) you pasted only the visible headers (From/To/Subject) and not the raw source, so the Received chain wasn't included; or (2) you forwarded the email to yourself and lost the original headers in transit. Re-do "Show Original" / "View raw" on the original message rather than a forward.
Either the sending domain didn't publish that record, or the receiving server didn't include the result in the Authentication-Results header. If you control the sending domain, publish all three records. If you don't, the absence is a deliverability signal - emails without authentication are routinely routed to spam by Gmail and Microsoft post-2024.
The first public IP in the chronological chain is the closest representation. Sometimes mail goes through a relay (ESP outbound IP) whose own outbound IP is what mailbox providers actually rate-limit and reputation-track. For ESP-sent mail this IP belongs to the ESP, not the customer. For directly-sent mail (self-hosted, transactional from your own server), this is your real sending IP.
No. Headers are processed in-memory only. The form submits to PHP, the analyzer parses and returns results, then the data is gone. We do not log, store, or retain any pasted content. The parser also stops at the first blank line - the message body is never inspected even if you paste it accidentally.