Is It Down?

How this "is it down" check works

When you enter a URL, your browser fires a request at the site with a strict timeout running in the background. We watch three outcomes: the request completes (the site is reachable from your network), it fails with a network error (a strong sign it's unreachable), or it times out before answering (inconclusive). Because the check happens on your device, the answer is specifically "can I reach it right now?".

We're deliberately honest about a hard browser limit: for most sites, JavaScript can't read the response of another origin, only whether the request went through. So we report up, down, or unknown — never a fake status code.

How to read your results

• Up — the site answered your browser in time. It's reachable from your connection.
• Down — the request failed at the network level. The host couldn't be contacted.
• Unknown — the result is ambiguous: a timeout, or a cross-origin block. Not proof either way.

If you see "down" but others can reach the site, the fault is probably on your side. Confirm with a ping to the host and a DNS lookup to isolate which layer is broken.

Frequently asked questions

How can you tell if a site is down from my browser?

We send a request to the site with a strict timeout. If it answers in time, the site is reachable from your network — "up". If the request fails outright, that points to "down". If nothing comes back before the timeout, we say "unknown" rather than guessing.

Why does it sometimes say "unknown" for a site I know is online?

Browsers protect your security by hiding the details of cross-origin responses (CORS). For many sites we can confirm the request completed but can't read the status code, and some sites block browser requests entirely. When the signal is ambiguous, an honest "unknown" is more useful than a false "down".

Is it down for everyone or just me?

This check runs from your own device, so it answers "can I reach it?". If you get "down" but friends can load the site, the problem is likely on your side — your DNS, your network, or your ISP's routing. That distinction is exactly what the full Doctor diagnosis untangles.

Can a real monitoring service do better?

Yes. A server-side monitor checks a site from multiple regions, reads the real HTTP status, and watches over time — so it catches outages a single browser check can miss. That's what our upcoming Uptime Monitor is for.

The site loads for me but this says it can't reach it. Why?

Your browser already has the page cached, or the site allows normal navigation but blocks scripted cross-origin requests. Both are common and don't mean the site is broken — it's a limitation of what JavaScript is allowed to see.