SiteGuard monitors every page you visit — tracking Web Vitals, HTTP errors, outages, and JS crashes — right from your browser.
SiteGuard works silently in the background, tracking the performance and reliability of every site you visit.
Tracks LCP, FCP, CLS, FID, TTFB and page load time in real time using the browser's native Performance APIs.
Automatically detects site outages when 3 or more consecutive HTTP 5xx errors are observed — with automatic recovery detection.
Captures uncaught JavaScript exceptions and unhandled promise rejections with file, line, and column details.
Intercepts fetch() and XMLHttpRequest calls to catch failed API requests, with URL, status code, and duration logged.
Color-coded alerts (critical / warning / info) with a 60-second cooldown to prevent notification spam.
Set your own performance budgets for every metric. SiteGuard flags breaches in real time against your thresholds.
SiteGuard ships with sensible defaults. Every threshold is adjustable in the Settings panel.
Three layers work together to give you full coverage with no backend required.
Add SiteGuard to Chrome. No account, no server, no API key needed.
The background service worker intercepts HTTP responses and the content scripts collect Web Vitals automatically.
The extension badge turns red on critical issues. Open the popup to see the full dashboard for the current site.
Adjust every performance budget in the Settings tab. SiteGuard saves your config locally in Chrome storage.
Every metric has a threshold you control. SiteGuard compares live values against your budgets and alerts you the moment a breach occurs.
No sign-up. No server. Everything stays in your browser.