Is it down?
When a page won’t load, either the site is broken or something between you and the site is. We request it from our server, so you’ll know which.
Why a second point of view settles it
Your request for a page leaves your device, crosses your Wi-Fi router, your internet provider and a DNS resolver, and only then travels to the site’s server. A failure anywhere along the way gives you the same blank tab. From your chair, a dead server and a confused router look exactly alike.
A request sent from a different network shares none of your equipment. If it gets an answer, the server is alive and the fault is on your side of the path. If it fails too, you can stop restarting your router.
What the check does, in order
- Name lookup. It asks a public resolver for the
A(IPv4) andAAAA(IPv6) records of the host. No address at all ends the check with “Not found”, and anNXDOMAINanswer tells you the name doesn’t exist. A host with only an IPv6 address gets a warning, since many networks still can’t reach it. - Request with certificate validation. It connects, sends a normal page request and follows up to six redirects one by one, timing each hop. A hop gets 8 seconds to connect and 15 seconds in total.
- Retry without validation. If the TLS certificate was the only obstacle, a second attempt ignores it. A site that answers this way is reported as “Certificate rejected”. It’s running, but every browser will show a warning.
- Plain HTTP. If HTTPS couldn’t connect at all, it tries
http://. - The other spelling. If everything failed, it tries the same domain with or without
www.and tells you when that one works.
Reading the verdict
| Verdict | What happened | Who has the problem |
|---|---|---|
| Up | A final status below 400, first byte within 5 seconds. | You, if the site won’t open. See the next section. |
| Slow | An answer, but more than 5 seconds before the first byte. | The site is overloaded. Some visitors will time out. |
| Error 500 to 599 | The server answered with a failure code. | The site, for everyone. |
| Refused 403 or 429 | The server is online and turned our request away. | Probably nobody. A firewall is filtering automated requests, and human visitors may get in. |
| Error 400 to 499 | The server is fine and this address isn’t, typically a 404. | The link. Try the home page. |
| Not responding | Timeout, refused connection, connection cut, or redirects that loop. | The site, for everyone. |
| Not found | The name has no address in DNS. | The domain: expired, or its records were deleted. |
Under the verdict you get the addresses found, the IP that was reached, the HTTP version, the time to connect and to the first byte, and the certificate issuer and expiry date. A certificate with fewer than 14 days left is marked, because no outage is easier to see coming.
When it answers us and not you
Work outward from your device:
- The browser
- Open the page in a private window. That rules out extensions and a damaged cookie in one step.
- The network
- Load the site on a phone using mobile data. If it works there, the cause is in your home or office network, or with your provider.
- DNS
- Run
nslookup example.comand thennslookup example.com 1.1.1.1. Two different answers mean your resolver is holding an old record. Clear the local cache (ipconfig /flushdnson Windows,sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponderon macOS) or switch the resolver to1.1.1.1or8.8.8.8. The DNS propagation check shows which resolvers have the new record. - A block aimed at you
- Sites often block company filters and VPN exit addresses. A server can also ban one IP address after several wrong passwords, and that locks out a whole office while the rest of the world gets in.
What one request can’t tell
This is a single attempt from a single location. A site that blocks some countries, or a CDN with trouble in one region, can answer us and fail for you with nothing wrong in your equipment. The check doesn’t run JavaScript either, so an application that returns status 200 and then shows an empty screen counts as up.
It isn’t a monitor. Nothing is tested again after you leave the page, so an outage that comes and goes may take several tries to catch.
Questions people ask
How can I tell if a website is down for everyone or just me?
Have it requested from a network that isn’t yours, which is what this page does. If an answer comes back from there, the server is running and the problem sits between you and it. If that request fails too, the site itself is down.
What is the difference between errors 500, 502, 503 and 504?
- 500: the site’s own code crashed, often after an update.
- 502: a proxy or CDN in front of the site received a bad answer from it.
- 503: the server is overloaded or in maintenance mode. Usually temporary.
- 504: the proxy or CDN waited for the site and gave up.
Why does the check report 403 when the site opens in my browser?
Many firewalls refuse requests that don’t come from a real browser. The server is online, and that’s the part you needed to know. Ordinary visitors are probably served normally.
The site is up here but still will not load for me. What should I do?
Try a private window, then a phone on mobile data, then compare DNS answers as described above. Between them, those three tests tell a browser problem from a network problem from a stale DNS record.
Can a website be down in one country only?
Yes. Sites and their firewalls can refuse whole regions, internet providers can block a domain, and a CDN can have an incident in one location. A single test from one place, like this one, can’t see that.
What does “Certificate rejected” mean for visitors?
The server works, but its TLS certificate is expired, issued for another name or incomplete. Browsers show everyone a full-page warning. The TLS certificate inspector says which of the three it is.