Every one of these reads live DNS in your browser. Nothing is stored, nothing reaches our servers, and none of them ask for an email address.
All four run on the same engine. They query your records against Cloudflare's public resolver from the page you are on, name the service that actually sends your mail, and report what they find without inventing the parts they cannot know.
The full picture. Reads MX, SPF, DKIM and DMARC in one pass, identifies your sending provider, and flags the failures that a DNS panel displays as healthy. Below it, a 15-question audit of your wider setup with a score and the specific fixes.
Reads the SPF policy at your apex, names the providers it authorises, and shows the raw record. Detects the two failures people miss: duplicate SPF records, which cause a permanent error, and a +all qualifier, which authorises the entire internet to send as you.
Probes 32 of the DKIM selectors used by the major providers and reports which returned a key. It also explains why an empty result is not proof of absence, which is something most DKIM checkers get wrong.
Queries _dmarc on your domain, reads the policy, and tells you plainly whether anything is enforced and whether aggregate reports are being collected. Most published DMARC records enforce nothing, and they look identical to ones that do until you read the policy tag.
Blocklist status. Spamhaus, Barracuda and the other major DNSBLs refuse queries arriving from public resolvers, so a browser has no way to ask. Any page showing you a live blocklist result is paying for a private feed or guessing. We do neither, so we do not claim it.
Inbox placement is a separate question again. Authentication is a precondition for landing in the inbox, not a guarantee: a domain can pass every check here and still go to spam on content, list quality or complaint rate.
We used the engine behind these tools to audit 156 lead generation agencies. Fifty-six percent of them carry a real defect on their own domain, and only 19% enforce DMARC. The method and raw counts are published with the study.