Every tool here takes a domain or a URL, performs a live lookup against a public data source, and reports what came back. A DNS check queries real public resolvers. An SSL check opens a real TLS connection and reads the real certificate. A WHOIS lookup queries the registry over RDAP.
None of these are hard problems, which is exactly the point. They are checks a site owner needs a few times a year, at the worst possible moment — mid-migration, mid-outage, or the morning a certificate expired. The value is that the answer is one field and one button away, and that it is correct.
How results are presented
A raw number on its own is not a result. Every value on this site is shown three ways at once: the measured value, a plain-language reading of it, and the threshold it was judged against.
So a certificate is never just expires 2026-09-14. It is that date, plus “39 days remaining”, plus the fact that the warning threshold is 30 days and why that number rather than another. If you disagree with the threshold, you can see it and ignore it. That is not possible when a tool only shows you a coloured badge.
Status is never carried by colour alone. Pass, warning and fail each have their own label and their own icon shape, so the result survives a screenshot, a greyscale print, and colour-blindness.
Why every result shows its working
Below each result is a transcript: a plain-text record of every query made, every answer received, the response time of each, and whether the answer was live or served from cache. It is ordinary selectable text, not an image.
There are two reasons for it. The first is verification — you can take any line out of a transcript, run the equivalent dig, openssl or curl command yourself, and get the same answer. The second is diagnosis. When three resolvers agree and a fourth does not, that disagreement is the finding. A tool that shows you one merged answer has thrown away the thing you came for.
What these tools cannot tell you
Public data has edges, and pretending otherwise would be the same sin as inventing a number:
- DNS answers are what a specific resolver held at a specific second. Cached records mean a resolver can report a value that is already stale at the authoritative nameserver.
- WHOIS and RDAP records are redacted for most private registrants under GDPR. Where the registry returns nothing, the page shows nothing — it does not fall back to a stale copy from elsewhere.
- Anything measured from our servers is measured from our network path, not yours. A site can be reachable for us and unreachable for you, and vice versa.
- Sites that block automated requests will block ours too. Our probes identify themselves honestly rather than pretending to be a browser, so some sites will refuse them.
Where a limit applies to a specific tool, it is written on that tool’s page, next to the result it affects.
How this site is funded
Affiliate commissions on hosting and domain registration. When a result shows a problem that one of those products genuinely solves — a certificate that has expired, a server that responds slowly from every region, a domain that is actually available — the page may suggest one, and we earn a commission if you buy.
Three rules keep that from corrupting the tools. A suggestion is only ever triggered by a finding, never by a page load and never by a passing result. Every suggestion states the problem before it names a product. And every commercial link is labelled as one where it appears. Full disclosure.