Email header analyzer
When a message lands in spam or fails authentication, its headers explain why. Paste the full headers into the analyzer to see which checks passed, whether they aligned with the sender's domain, and how the message travelled. The headers never leave your browser.
- Free, no subscription
- No account
- Part of the Email Security Checker
What it checks
- SPF, DKIM and DMARC results as reported by the receiving server.
- Whether SPF and DKIM align with the From domain, which is what DMARC actually requires.
- The DKIM signing domain and selector, with one click to check that domain's DNS.
- Every hop in the delivery path, in order, with the delay at each step.
- One-click unsubscribe headers required for bulk mail, and Microsoft's spam confidence level.
How to get the full headers
In Gmail, open the message, choose the three-dot menu and Show original. In Outlook on the web, open the message's menu and view the message source; in Outlook desktop, open the message's Properties. Copy everything from the first header line down to the first blank line and paste it in. Use a message you received, not one from your Sent folder, because only the received copy carries the receiver's authentication results.
Reading the verdict
DMARC passes when SPF or DKIM passes and aligns with the From domain. A common surprise is SPF passing for a sending service's own domain: it passes, but doesn't align, so it doesn't help DMARC. If DKIM is aligned, the message still passes. If neither aligns, the message fails DMARC even though nothing looks broken.
Frequently asked questions
Are my headers uploaded anywhere?
No. The analyzer runs entirely in your browser; nothing you paste is sent to ToolVeriq or anyone else.
Why does SPF pass but DMARC fail?
SPF passed for a different domain than the From address, usually the sending service's bounce domain, so it isn't aligned. DMARC then needs aligned DKIM.
Which header shows the authentication results?
Authentication-Results, added by the receiving server. The analyzer reads the topmost one, which belongs to the final receiver.
Can it tell why a message went to spam?
It shows the authentication results, alignment and spam score the receiver recorded. Content and reputation filters also play a part and aren't visible in headers.
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