⌘K
Web Checker — Pageload
Pageload monitors launch a real Chromium browser (Playwright) to load your page exactly like a visitor would. Designed for performance monitoring — measure how fast your page loads, track Web Vitals over time, and get alerted when performance degrades. No scripting required — just enter a URL.
Web Vitals & timing metrics
| Metric | Name | What it tells you |
|---|---|---|
| TTFB | Time to First Byte | How long until the browser receives the first byte from the server. High TTFB points to slow server processing, DNS issues, or network latency. Under 200 ms is good; above 600 ms needs investigation. |
| FCP | First Contentful Paint | When the browser renders the first piece of visible content (text, image, or canvas). This is the moment your page stops being blank. Under 1.8 s is good; above 3 s feels slow to users. |
| LCP | Largest Contentful Paint | When the largest visible element (hero image, heading block, video poster) finishes rendering. This is the best proxy for "the page looks ready." Under 2.5 s is good; above 4 s means users are waiting too long for the main content. |
| CLS | Cumulative Layout Shift | How much the page layout shifts unexpectedly while loading (ads popping in, images resizing, fonts swapping). It's a score, not a time — under 0.1 is good; above 0.25 means things are jumping around and annoying your visitors. |
| DOM Interactive | DOM Interactive | When the HTML document has been fully parsed and the DOM is ready for JavaScript to manipulate. Render-blocking scripts and large HTML payloads push this number up. |
| DOMContentLoaded | DOMContentLoaded Event | When the HTML and all deferred scripts have finished executing. A big gap between DOM Interactive and DOMContentLoaded usually means heavy synchronous JavaScript. |
| Load Event | Window Load | When the entire page — including images, stylesheets, iframes, and fonts — has finished loading. This is the "everything done" marker. |
What each probe captures
- Web Vitals — TTFB, FCP, LCP, and CLS measured from the real browser rendering pipeline.
- Page timing — DOM Interactive, DOMContentLoaded, and Load Event timestamps.
- HAR waterfall — Full HTTP Archive of every network request the page made, with timing, size, and status. Download and inspect in any HAR viewer.
- Screenshots — Optional viewport or full-page screenshot captured after the page loads.
- Console log — All console messages (errors, warnings, info) emitted during page load, with counts for each severity.
- Resource summary — Total resource count, error count, and total bytes transferred.