The Server Status Checker pings websites and servers to see if they're online and measures response time. Enter one URL per line to check multiple servers simultaneously. Results show UP/DOWN status with millisecond response times.
Check Server Status
Browser limitation: Due to browser security (CORS policy), this tool detects if a server responds but cannot read the HTTP status code (200, 404, 500). For detailed HTTP inspection, use curl from a terminal or the HTTP Headers Viewer below for CORS-enabled URLs.
Checking servers...
Results
How to Use the Server Status Checker
The Server Status Checker uses the browser's Fetch API to test whether servers respond to HTTP requests. It measures response time with microsecond precision using performance.now().
Step 1: Enter URLs
Type or paste one URL per line. URLs should include the protocol (https:// or http://). If you enter a domain without a protocol, https:// is added automatically.
Step 2: Check Status
Click Check Status. All URLs are checked in parallel. Results appear as each check completes — you don't have to wait for all checks to finish.
Understanding Results
- UP (green) — the server responded within the timeout window
- DOWN (red) — no response received (network error, timeout, or CORS block)
- Response time — time in milliseconds from request sent to first response byte
Browser Security Limitations
Due to browser CORS policy, this tool uses no-cors mode which means some servers may show as DOWN even when they're up (if they actively block script fetch requests). For production uptime monitoring, use dedicated tools like UptimeRobot, Pingdom, or a simple server-side script that can make unrestricted HTTP requests.
FAQ
How does this server status checker work?
The tool uses the browser's fetch() API with no-cors mode to attempt a connection to each URL. It measures response time using performance.now() before and after the request. Because of browser security restrictions (CORS policy), it can detect whether the server responds but cannot read the HTTP status code or response body.
Why can't I see the HTTP status code (200, 404, 500)?
Browser security restricts what information JavaScript can read from cross-origin requests. In no-cors mode, the browser only reveals whether a response was received, not the status code or headers. For detailed HTTP status codes (200 OK, 301 redirect, 500 error), use curl from a terminal or a server-side monitoring tool.
A server shows UP but I can't access it in my browser — why?
The tool detects whether the server sends any response. A server can respond (showing UP) but return a 403 Forbidden, 404 Not Found, or serve maintenance content. 'UP' only means the server is reachable — not that the content is correct. Use the HTTP Headers Viewer for a more detailed check on CORS-enabled URLs.
Can I check multiple URLs at once?
Yes. Enter one URL per line in the input field and click Check Status. The tool checks all URLs in parallel and shows results with individual status indicators and response times for each URL.
What response time is considered good?
Under 200ms is excellent (typically same-region CDN or nearby server). 200-500ms is good for a well-optimized server. 500ms-1s is acceptable. Over 1 second suggests slow server response, heavy pages, or geographic distance. Response time from your browser includes network latency to the server, so results vary based on your location.
Why does a site show as DOWN when I can open it in my browser?
Some servers block fetch requests from scripts (via CORS or firewall rules) even though they serve normal browser traffic. If a server doesn't send CORS headers, the browser blocks the response from being read — the tool may interpret this as DOWN. This is a browser security limitation, not a true downtime detection failure.