How to Check If a Website Is Down

Step 1: separate a typo from an outage

Check the address first. A wrong subdomain, a missing letter or http:// on a site that only serves https:// looks exactly like an outage. Paste the address into the Website Status Checker, which tests it from your own browser and network and shows whether the server answered.

Step 2: is it down for everyone or only for you?

A single check only tells you what your connection can reach. To compare, try another network, such as mobile data, or ask a colleague in another location to load the page. If it works elsewhere, the problem is local: your DNS cache, a VPN, a proxy, a firewall or your ISP.

• Turn off the VPN or proxy and reload.
• Try a different DNS resolver such as 1.1.1.1 or 8.8.8.8.
• Flush the local DNS cache (ipconfig /flushdns on Windows, sudo dscacheutil -flushcache on macOS).
• Open the page in a private window to rule out extensions and cached redirects.

Step 3: read the HTTP status code

If the server answers, the status code says what kind of problem it is.

• 200 OK: the page loaded. A blank page after this is a front-end problem, not an outage.
• 301, 302, 307, 308: the address redirects. Follow the redirect target.
• 401 Unauthorized and 403 Forbidden: the server is up but refuses you, often because of missing credentials or a blocked IP.
• 404 Not Found: the server is up but that path does not exist.
• 429 Too Many Requests: you are being rate limited.
• 500 Internal Server Error: the server is up but the application failed.
• 502 Bad Gateway and 504 Gateway Timeout: a proxy or load balancer could not get a good answer from the application behind it.
• 503 Service Unavailable: the server is overloaded or in maintenance.

Step 4: test from the command line

curl shows the status code and timing and separates DNS, connection and TLS failures.

# Status code and total time
curl -s -o /dev/null -w "%{http_code} %{time_total}s\n" https://example.com

# Headers only, with connection details
curl -I -v https://example.com

# DNS only
dig +short example.com

Checking from code

A HEAD request is enough to read the status. In Python the standard library raises an exception for 4xx and 5xx answers, so catch it.

import urllib.request, urllib.error

def status(url):
    req = urllib.request.Request(url, method="HEAD")
    try:
        with urllib.request.urlopen(req, timeout=10) as r:
            return r.status
    except urllib.error.HTTPError as e:
        return e.code          # the server answered with 4xx or 5xx
    except Exception as e:
        return str(e)          # DNS, TLS or timeout problem

What a browser-based checker can and cannot tell you

A checker that runs in your browser can only report what your own connection can reach. Many sites do not let other pages read their response, so the tool may confirm that the server answered without showing the exact status code. It is a quick first check, not a worldwide uptime monitor. For continuous monitoring from several regions, use a dedicated uptime service.