PerfDebugger — Real-time Web Performance

Real-time Core Web Vitals, re-render detection, slow-resource and memory-leak alerts for frontend developers. 100% local.

PerfDebugger shows Core Web Vitals as you browse — instantly. No 60-second Lighthouse audits. No simulated devices. Just real metrics from your real browser, updated live. Built for frontend developers who debug performance daily. WHAT YOU GET • Real-time Core Web Vitals: LCP, FCP, CLS, INP, TTFB — color-coded good / needs improvement / poor • Re-render detection for React, Vue and Angular — see which components re-render and how often, live • Automatic slow-resource detection (flags requests over 1 second — configurable) • Live memory monitoring with JS heap tracking and memory-leak alerts • Dashboard with every page you've tested: trends, median and p75, sortable and filterable • Per-URL history with sparkline trend charts • Export a single page or everything as CSV or JSON • Configurable thresholds, slow-request cutoff and data retention • Framework-agnostic — works on any website • 100% local, no tracking, no servers, no account RE-RENDER DETECTION Interact with your app and PerfDebugger shows the components that re-render the most. React and Vue work on development and production builds; Angular requires a development build (ng serve). PerfDebugger reads framework internals without installing a DevTools hook, so React DevTools and Vue DevTools keep working normally. WHY NOT LIGHTHOUSE? Lighthouse is great for formal audits and CI pipelines — but it takes 30-60 seconds per run, uses simulated throttling, and doesn't measure real interactions in navigation mode. PerfDebugger is the opposite: instant results, real device data, always visible. Different tools for different jobs. PRIVACY FIRST All metrics are stored locally in your browser. Nothing leaves your machine. No analytics, no tracking, no accounts. Old data is deleted automatically (7 days by default). PERMISSIONS • storage — save metrics and your settings locally • alarms — schedule automatic cleanup of old data • Access to all websites — run the measurement script on the pages you visit (it only reads performance data, never page content) Free and open source (MIT). No sign-up required. Source code: https://github.com/MonicaAvilaAlcazar/PerfDebugger Support: support@monydevelop.me