traceOn

Turns raw browser performance traces into a plain-language diagnosis of what's slow, why, and what to fix first.

traceOn turns a raw browser performance trace into a plain-language diagnosis of what's slow on a web page, why, and what to fix first. Most performance tools hand you a flame chart and leave the interpretation to you. traceOn does the interpretation. You click Record, it captures a DevTools-Protocol trace of the tab you choose, analyzes it entirely on your own machine, and gives you a readable report. What you get from one recording: • A performance score with the specific reasons behind it — not just a number. • Core Web Vitals — LCP, CLS, INP, FCP, TTFB and Total Blocking Time, each explained in context. • Ranked bottlenecks — the handful of things actually costing you load time, ordered by impact, with the long tasks and scripts responsible. • Diagnoses — concrete problems traceOn detected (render-blocking resources, layout thrash, oversized main-thread work, late LCP element, and more), each with a confidence level. • Recommendations — prioritized fixes with their expected impact, tailored to the framework it detects on your page. • A "Load Story" timeline — a narrative walkthrough of how the page came together, millisecond by millisecond, instead of a wall of trace spans. More tools built in: • Security checks — response-header analysis (CSP, HSTS, X-Frame-Options and others) plus cookie metadata review (Secure/HttpOnly/SameSite flags, oversized cookies) for the page under analysis. • Responsive preview — view your page at multiple device sizes side by side. • DevTools panel — a convenience panel for a quick Web Vitals read without a full recording. • AI assistant (optional) — ask questions about your own analysis; it works from a compressed summary, never your raw trace. • Community tab (optional) — anonymized, domain-level score aggregates, top-site lists, and a Q&A board. Privacy: All analysis happens locally. traceOn works fully with no account and no network connection. Every feature that sends anything off your device is off by default and clearly labeled. No ads, no third-party trackers, no data sales. Full policy: https://traceon-community.solomon-muhye-wd.workers.dev/privacy Made for: web developers, performance engineers, and anyone who needs to know why a page feels slow.