What each check means
SPF lists which servers may send as your domain. We count its DNS lookups: over 10 and receivers ignore the record. DKIM signs each message with a key published in DNS; we try 15 common selectors and any you enter. DMARC tells receivers what to do when SPF and DKIM fail, and where to send reports. MX shows where replies land; a sending domain with no MX cannot receive replies or bounces. Age comes from the registry; domains under 30 days get filtered harder.
What this cannot see
Inbox placement, spam complaint rate and reputation live inside Gmail and Outlook, not in DNS. For those, verify the domain in Google Postmaster Tools and Microsoft SNDS. This check tells you whether the foundation is right; it cannot tell you how the house is standing.
Questions
Why does the check say no DKIM found when I have DKIM?
DKIM keys live under a selector name that only you and your provider know. We try 15 common ones. Enter your selector in the optional field and run it again.
What DMARC policy should a cold email domain use?
Start at p=none with a rua address to collect reports. Once reports show your mail aligned and passing, move to p=quarantine, then p=reject.
How many SPF lookups is too many?
The limit is 10. Google Workspace alone uses 4. Past 10, every receiver treats the record as a permanent error.
Do you store the domains people check?
No. Lookups run against public DNS and results are cached for five minutes to reduce load. Nothing is logged against a visitor.
