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Simple Uptime Monitor - Online Check Website Status from Your Browser

Developer Tools Monitor check monitor uptime website
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Uptime Monitor

Check website status & response time directly from your browser. Monitor multiple URLs with automatic refresh.

Total Monitors
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Online
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Down
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Avg Response
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Use {url} as placeholder, e.g. https://proxy.example.com/?url={url}
Bulk Import URLs

Paste up to 20 URLs, one per line. Default interval & proxy settings will be applied.

No monitors yet

Add a website URL above to start monitoring its uptime.

Recent Check History
URL Status Response Time Action
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Frequently Asked Questions
What is an uptime monitor?

An uptime monitor periodically checks if a website or web service is accessible and responding. It helps you detect downtime early, measure response times, and ensure your online services are running smoothly. This tool performs checks directly from your browser using HTTP requests.

How does browser-based uptime monitoring work?

This tool uses the browser's fetch API to send HTTP requests to the target URLs. It measures the round-trip time and determines if the site is UP (responds successfully) or DOWN (request fails). For sites with CORS restrictions, you can optionally use a CORS proxy to get more detailed status information.

What are the limitations of browser-based monitoring?

Due to browser security policies (CORS), direct requests to external websites may return limited information. When using "Direct" mode, the tool can detect UP/DOWN status and measure response time, but cannot retrieve exact HTTP status codes (like 404 or 500). For detailed status codes, use a CORS proxy. Also, monitoring stops when you close the browser tab.

How often should I check my website?

For critical production services, checking every 30-60 seconds is common. For less critical sites, 5-10 minute intervals are sufficient. Shorter intervals provide faster downtime detection but consume more resources. This tool supports intervals from 30 seconds to 30 minutes, or manual-only checks.

What does response time mean?

Response time is the total time (in milliseconds) it takes for the server to respond to an HTTP request. It includes DNS resolution, TCP connection, TLS handshake (for HTTPS), and server processing time. Generally, <200ms is excellent, 200-500ms is good, 500-1000ms is average, and >1000ms may indicate performance issues.

Why is my website showing as DOWN when I can access it in my browser?

This can happen due to CORS restrictions, firewall rules blocking automated requests, or the site requiring JavaScript rendering. Some sites block non-browser requests or require specific headers. Try switching to a CORS proxy mode or check if the site uses CDN/DDOS protection that may block automated checks.

Can I monitor multiple websites simultaneously?

Yes! You can add as many URLs as you'd like. Each URL is monitored independently with its own refresh interval. Use the "Bulk Import" feature to add up to 20 URLs at once. All monitors run concurrently, and you can pause or resume individual monitors as needed.

What is a CORS proxy and when should I use it?

A CORS proxy is an intermediary server that adds CORS headers to responses, allowing browsers to read detailed HTTP response data (status codes, headers) from any website. Use a proxy when you need to see exact HTTP status codes (200, 404, 500, etc.) rather than just UP/DOWN status. Public proxies like corsproxy.io are available, or you can use your own.

Is my monitoring data saved?

Yes, your monitor list and recent check history are saved to your browser's localStorage. Data persists when you reopen the page but is limited to this device and browser. No data is sent to any external server. You can clear all stored data at any time using the "Clear All" or "Clear History" buttons.

What HTTP methods does this tool use for checking?

The tool uses HTTP HEAD requests when possible (via proxy), which are lighter and faster as they only fetch headers without the response body. In direct mode, it uses a no-cors GET request. Both methods effectively measure server availability and response time without downloading page content.

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