Resource waterfall
Waterfall chart of all static page resources — Full page speed audit.
How this tool works
Resource waterfall analyses every resource a page loads — the full page-speed audit workflow: which resources does the page load (HTML, CSS, JavaScript, images, fonts, iframes, XHR/fetch), how large is each one, how long does it take (DNS resolution, TCP connect, TLS handshake, TTFB, total) and which third party is behind it? We load the page in a real headless Chromium, so we see exactly what a visitor sees — including JavaScript-injected requests, defer/async ordering and lazy loading.
Typical use cases
- Before relaunch: does the new WP builder bog down the page with too many JS bundles?
- Third-party audit: how many external domains does the page load — does it match the cookie banner list?
- Size optimisation: identify the largest image in the waterfall and convert (WebP, lazy-load)
- TTFB bottlenecks: which resource has the longest wait (TTFB)?
- Cache audit: are many resources loaded fresh instead of from CDN cache (404 / cache-miss suspicion)?
- Before a Lighthouse run: sanity-check the resource list
Frequently asked questions
How accurate is the measurement compared to a real browser?
Very close — we load the page in a real headless Chromium (same engine as Chrome). DNS, TCP, TLS, TTFB and total per resource come directly from browser network events. JavaScript-injected fetch/XHR requests, defer/async timing, HTTP/2 connection reuse and connection pool limits are all visible. Compared to Chrome DevTools we miss: browser cache hits (we always start with an empty cache — the first-visit worst case which matters more for audits) and service worker optimisations.
Are JS-loaded requests captured too?
Yes. Since we run the page in a real browser, we capture everything — fetch/XHR from JavaScript, dynamically created script tags, lazy-loaded images via IntersectionObserver, web fonts loaded via CSS @font-face, tracker pixels loaded by analytics libraries.
Are all resources measured?
In the browser up to 200 resources are captured, including ones loaded via JavaScript — larger pages are truncated in order of appearance. If the browser cannot load the page, the tool reads the HTML instead: then up to 80 resources and no JavaScript late-arrivals.
What does the "3rd" badge mean?
The resource is not on the own domain but on a foreign host (CDN, tracker, font provider, etc.). We match via eTLD+1, so `www.example.com` and `cdn.example.com` count as same site. On GDPR-relevant sites you should know which third parties are active — the cookie scanner adds detail per third party.
Why does a test take 2-5 seconds?
The headless browser must fully load the page including JavaScript execution. We additionally wait for network idle (short phase without new requests), so JS late-arrivals are captured. That is considerably more expensive than a simple HTTP GET, but the data is realistic.
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