Runs entirely in your browser. Alignment uses a simple rule for the organizational domain (last two labels, three for suffixes like co.uk), so treat it as approximate.
How to use it
- Send a normal email from the mailbox (and tool) you want to test to a Gmail or Outlook.com account you own.
- In Gmail open it, click the three dots and choose Show original, then Copy to clipboard. In Outlook on the web use View, then View message source.
- Paste it above and read the checklist. Fix the first failure, send a new test, and check again.
What it checks
The SPF, DKIM and DMARC results the receiving server wrote into Authentication-Results (or ARC-Authentication-Results), every DKIM signature and its domain, whether the From domain lines up with the DKIM and SPF domains, Microsoft's spam verdict (SFV, CAT, SCL and composite authentication) and SpamAssassin scores when present, TLS on each hop, the delay from Date to delivery, List-Unsubscribe and one-click unsubscribe, Message-ID and Date.
What it can't tell you
Gmail doesn't write a spam score into the headers, so for Gmail the folder the test landed in is the verdict. One test email is one snapshot: it shows your setup works, not where every recipient's copy lands. Alignment here uses a simple rule for the organizational domain (the last two labels, three for suffixes like co.uk), so it's approximate; the receiver's own DMARC result is the one that counts.
Private by design
The analyzer runs in your browser. The text you paste isn't uploaded, stored or logged, and the page doesn't load anything when you check. Headers can still contain addresses and IPs, so don't paste someone else's mail into tools you don't trust.
Questions people ask
How do I see the full headers of an email?
In Gmail, open the email, click the three dots next to Reply and choose Show original. In Outlook on the web, open it, use the three-dot menu, then View and View message source. In Yahoo Mail, choose More, then View raw message.
What does dmarc=fail mean if SPF and DKIM pass?
They passed for a domain that isn't your From domain, usually a sending tool's own domain. Have the tool sign DKIM with your domain, or send through your own mailbox.
What is SCL in Outlook headers?
Microsoft's spam confidence level, from -1 to 9. -1 means filtering was bypassed and 5 or higher generally means spam. In Microsoft 365 the SFV and CAT values in X-Forefront-Antispam-Report say more about how the message was filtered, so the analyzer reads those first.
Is this an email deliverability test?
It's the part you can check for free on one email: whether it was authenticated and accepted, and how. For placement across many mailboxes you need a seed-list test; our deliverability test guide lists free ones.
Is my email sent anywhere?
No. The analyzer runs in your browser and makes no network requests with what you paste.