How to use this check
Paste message headers in the browser to inspect Authentication-Results, Received-SPF and DKIM-Signature lines locally.
The analyzer unfolds header lines in the browser and extracts only authentication status clues for display.
Choose an amount before the secure payment page opens.
Message headers
Browser-side onlyHeader Analyzer
Parse raw message headers locally to summarize SPF, DKIM, DMARC and alignment clues.
Health score--Browser-side only
Signal checklist
The result summarizes authentication signals, detected domains and privacy-safe warnings.
Header Analyzer
Paste message headers in the browser to inspect Authentication-Results, Received-SPF and DKIM-Signature lines locally.
Result
Paste raw message headers before running the analyzer.
Support
Keep this free result available
Use the result first. Support and promotional areas stay separate from the useful result.
- Useful result first
- No signup required
- Promotions kept separate
Choose an amount before the secure payment page opens.
Guide and interpretation
How to interpret the result
Authentication-Results from the receiving system is usually more trustworthy than a sender-provided claim.
Example
A header with spf=pass dkim=pass dmarc=pass and aligned From/Return-Path domains is generally healthier.
Common issues and next steps
Forwarding and mailing lists can change Return-Path or body signatures, causing SPF or DKIM to fail.
Compare Authentication-Results, From, Return-Path and DKIM d= domains before changing DNS.
Methodology and limits
Headers can contain personal addresses and message IDs; the free analyzer never sends them to an API.
FAQ
Are pasted headers uploaded?
No. Header analysis runs in the browser and does not use localStorage, sessionStorage or a product API.
Can this prove a message is legitimate?
No. Header analysis is one signal and must be combined with sender, content and account context.