Tools
Check any domain in seconds
One place for checks: who owns a domain, whether DNS is healthy, when a certificate expires, whether mail is landing in spam. Free, no sign-up.
Core tools
Who owns the domain, paid until when, what’s happening with the site, mail and certificate, at a glance.
OpenDNS diagnosticsAll records per name server separately, TTL in words, mismatches between servers.
OpenCertificate checkFour states in words: none, ours, foreign, problem. Expiry, issuer, “Install automatically”.
OpenMail checkMX, SPF with a DNS lookup count, DKIM by selector, DMARC.
OpenSite uptimeResponse code and time from three points, the redirect chain.
Open.UA zone statusDaily domain deletions and other aggregates from Hostmaster’s public statistics.
OpenCertificates and keys
Four of the five run in the browser itself: neither the request, nor the key, nor the password leaves the tab.
A certificate request and the private key for it. Both are computed in your tab.
OpenCSR and certificate decoderWhat a request or certificate actually says: domains, validity, algorithm, issuer.
OpenKey and certificate — a pair?Match a private key against a certificate before you put them both on a server.
OpenPassword generatorA password from the browser’s randomness source, with an honest strength count.
OpenTLS vulnerabilitiesOutdated TLS versions, weak ciphers, forward secrecy, HSTS — on your own domain.
OpenThe CSR generator, decoder, key match and password generator work without a server. Only the vulnerability check goes to our probes — it has to connect to the host.
More tools
More specialised checks — for those who need exactly these.
Want us to keep watching this and tell you the moment something changes?Monitoring
Frequently asked
Why check someone else’s domain?
Owners check whether their own domain is fine, buyers check whether a taken name can be obtained, agencies check what’s expiring across their clients. The data is public — the registry shows the same thing to anyone.
Do you store what I checked?
A raw request lives no longer than 72 hours. Every checked name goes on an internal 90-day block list, so we can’t front-run it or get an advantage from it ourselves.
Is it really free?
Yes, no sign-up and no hidden limits on a one-off check. The paid tier is ongoing monitoring with alerts.
Can I get a link to the result?
Yes, the result link lives and can be shared, but such pages don’t reach search: only the tool pages themselves are indexed.