Email Header Analyzer

Paste your raw headers or a full raw email. Instantly visualize the hop chain, delays, IPs, SPF/DKIM/DMARC authentication and spam scores.

Understanding email headers

Email headers contain the complete history of the path a message took from sender to recipient. Every server that handles the message prepends a 'Received:' header recording where it came from, where it is going, the protocol used, and a timestamp. This information is essential for diagnosing delivery problems, identifying slow servers, or detecting misconfigurations.

The Authentication-Results header records whether the email passed SPF (was the sending IP authorised?), DKIM (is the message signed and unmodified?), and DMARC (do SPF/DKIM results align with the From domain?). A 'pass' for all three ensures the best deliverability. X-Spam-Score and X-Spam-Status headers reveal the anti-spam verdict of intermediate servers.

🔗

Full hop chain

Visualize every hop with source IP, destination server, protocol (SMTP, TLS) and the precise delay between each step.

🔐

Detailed authentication

SPF, DKIM, DMARC and ARC clearly interpreted. Instantly identify authentication failures causing delivery problems.

⚡

Delays and performance

Identify slow or overloaded servers delaying your emails. Total and per-hop delays highlighted in red when problematic.

Frequently asked questions

Email headers are metadata fields prepended to every email message. They record the path the email took, authentication results (SPF, DKIM, DMARC), timestamps, and anti-spam verdicts. Not normally visible to end users, they are essential for diagnosing delivery problems.
In Gmail: open the message, click the three-dot menu and choose 'Show original'. In Outlook: open the message, go to File > Properties and copy the 'Internet headers' field. In Apple Mail: use View > Message > All Headers. You can paste the full raw email, the body will be automatically stripped.
Each time an email passes through a mail server, that server prepends a 'Received:' header recording where it came from, where it is going, the protocol, and a timestamp. The hop chain shows these servers in chronological order (oldest first), with the delay between each hop. Unusually long delays identify slow or overloaded servers.
The Authentication-Results header records the outcome of SPF (was the sending IP authorised?), DKIM (is the message signed and unmodified?), and DMARC (do SPF/DKIM align with the From domain?). A 'pass' for all three is ideal. 'fail' or 'none' indicates a configuration problem that can cause emails to land in spam.
Header analysis reveals exactly where an email was delayed, which server rejected or modified it, whether authentication passed at every hop, and which anti-spam systems flagged it. Look for large delays, 'fail' in Authentication-Results, a high X-Spam-Score, or unexpected relay servers.

Go further with a full audit

Header analysis is the first step in diagnosis. Run a Sender Audit to verify SPF, DKIM, DMARC, TLS, blocklists and IP reputation in real time.

Run a free audit

Other free tools

SPF Checker DKIM Checker DMARC Checker Blocklist Checker