One check for the things that quietly take a business offline: expiry dates, certificates, DNS, email authentication and reputation.
Most domains do not fail dramatically. They fail on a date nobody had in their calendar: a certificate lapses, a registration quietly expires, an SPF record gets one include: too many and invoices start landing in spam. Each of those is preventable, and each one is usually found by a customer rather than by the business.
This runs the checks that actually cost money when they are wrong — registration and certificate expiry, DNS, email authentication, reachability and IP reputation — and puts them in one place, ordered by what to deal with first.
Nine checks, weighted by what it costs you when each one breaks rather than treated as an even list:
Each check contributes according to consequence. DNS failing is worth far more than a missing IPv6 record, because one means nothing works and the other means a slightly longer path for some mobile users.
Anything we could not check counts as unknown and is left out of the score entirely — not counted as a failure. Blocklists rate-limit shared resolvers, and some registries do not publish expiry data. Marking a domain down for that would make the number meaningless, which is the usual failing of scored health tools.
Certificate and registration expiry are worth singling out, because they are the only failures on this list with a known date in advance. They are entirely preventable and they still take businesses offline every week — usually because the renewal notice went to an inbox nobody reads, or the card on file expired before the domain did.
If you check nothing else here regularly, check those two. A certificate under 30 days or a registration under 60 is worth acting on now rather than at the deadline.
This is a snapshot, not monitoring. It says the domain is healthy at the moment you ran it, which is the right answer to "is something wrong right now" and no help at all against a certificate that expires next month while you are not looking.
It also checks configuration rather than content: it will not tell you a page is slow, a form is broken or a price is wrong. For per-region response times use the global HTTP check; for continuous checks, the uptime monitor.
No. Enter a domain and you get the report. Nothing is stored against you and there is no sign-up.
Yes. Every check here uses public information — DNS records, the certificate the server presents, public registration data and public blocklists. Nothing requires access to the domain.
Because we could not get a reliable answer, usually a blocklist declining our query or a registry that does not publish expiry data. Treating that as a failure would punish a healthy domain, so unknown checks are excluded from the score.
Warnings count as half. Things like a missing IPv6 record, DMARC set to monitor-only, or no MX record are not faults exactly, but each is worth a decision rather than an accident.
Monthly is enough for a stable site, and worth running after any DNS, hosting or email change — those are when things break. The expiry dates are the ones to diarise.