Website checker
Is it up, where does it redirect, when do its certificate and domain expire, and what does its DNS say? One address, one report.
How it works
Type a domain or a full address. Each check runs separately on our servers, so the report fills in section by section instead of waiting for the slowest one.
- 1We keep the hostname onlyFrom https://shop.example.com/cart?token=… we keep shop.example.com. Private and internal addresses are refused.
- 2Five checks in parallelReachability from each region, the redirect chain, the SSL certificate, DNS records and the domain's registration.
- 3Plain verdictsWarnings come with one line on why. If we can't tell, we say “Couldn't check”, never “Down”.
Worked example: reading a report for example.com
The only thing to act on is the domain. Everything else is healthy, so the report shows a single warning.
Why a site can be up for you and down for others
Your browser may still use a cached copy or an old DNS answer. Your network might route around a problem that others hit. Sites can also block whole countries, cloud networks or a busy edge server in one region. That's why we show each region we check from, rather than one yes or no.
What “propagation” really means
Nothing is pushed around the internet when you change a DNS record. Resolvers that already asked keep their cached answer until its TTL (time to live) runs out, then ask again. “Waiting for propagation” is waiting for those caches to expire. Lower the TTL a day before a planned change and the switch takes minutes instead of hours.
Why we don't store the URLs you check
Addresses often carry more than people realise: password-reset links, session tokens, private file paths. We cut every address down to its hostname before the check runs, hold hostnames in memory for about a minute for rate limiting, never write them to disk, and put only the hostname in shared links.
Frequently asked questions
Is it down for everyone or just me?
If our regions reach the site and you can't, the problem is between you and the site: your connection, a cached DNS answer, or a block where you are. If two or more regions all get a clear error, it's down for everyone.
Why does it say “Couldn't check” instead of “Down”?
Some sites block automated requests or our network, and a timeout doesn't prove anything is broken. We only say Down when two or more regions all get a clear error. With a single region, a clear error reads Not responding.
Where do the checks run from?
From our servers in [1 region: US East] at launch, with more to come. Each row in the report says where the check ran and at what time.
How many checks can I run?
Each IP address can run 60 checks an hour and 20 a minute. A full report counts as 5 checks, so that is 12 full reports an hour. If you reach the limit, wait a few minutes. For regular checks, use the API or a monitoring service.
Is there an API?
Yes. Every check on this site is available as a free JSON API. Tools for AI assistants are planned for later. See the API page in the menu.