Certificates, domains and DNS records all fail on a date nobody wrote down. These check them in a second. No account, no email, no limits worth mentioning — use them whether or not you ever become a customer.
Who issued a certificate, when it expires, and how many days are left.
The A, AAAA, CNAME, MX, NS and TXT records a domain is publishing right now.
Whether independent resolvers agree on your DNS yet, or are still serving the old record.
When a domain registration lapses, and who it’s registered with.
Your domain’s SPF, DMARC and DKIM setup — including the lookup limit that breaks SPF silently.
The route a message took, where the time went, and what the receiving server concluded about SPF, DKIM and DMARC.
One email a week if your certificate, domain or email setup needs attention.
What an hour offline costs you, and what 99.9% uptime really allows.
Because they answer a question once, and the useful version of the answer is the one that keeps arriving. Checking a certificate today tells you it's fine today — it doesn't help in four months when it quietly expires on a Sunday. That's what a monitor is for, and that's what we sell.
So run these as often as you like. If you eventually want them run for you, create a free account — 25 monitors, without a card.
These tools only ever read what a domain publishes publicly — a single certificate handshake, a DNS query, or a registry lookup. Nothing is written, nothing is scanned, and every request identifies itself as UptimeTwin/1.0 (+https://uptimetwin.com) in your logs.
If you'd still prefer we skipped your domain entirely, publish a TXT record at _uptimetwin-optout.yourdomain.com with any value. We check for it before every lookup and stop within the hour. No form, no account, no reply needed.