DevPulse

Real-time performance HUD for web developers. Monitor FPS, DOM nodes, memory, CLS, and Core Web Vitals — right on the page.

Performance bugs are 10x harder to fix after launch. DevPulse gives you a real-time performance heads-up display that floats right on the page you're building — so you catch regressions the moment they happen, not when users complain. Built for localhost-first development, DevPulse auto-activates on your dev server and persists across hot reloads and page refreshes. One click on any other page and it works there too. WHY MONITOR DURING DEVELOPMENT? Most performance issues creep in one component at a time — an unthrottled scroll handler, a render loop that doubles DOM nodes, a layout shift you don't notice on a fast machine. By the time these stack up in production, tracing the root cause is painful. DevPulse keeps metrics visible while you code, so you spot the exact change that tanks performance. FREE METRICS - FPS counter with sparkline history — see frame drops as you interact - DOM node count with trend visualization — catch runaway renders instantly - Color-coded thresholds (green/yellow/red) — glanceable health at all times PRO METRICS ($2.99 lifetime) - JS heap memory usage — find leaks before they snowball - Long Task detection with activity badge — flag main-thread bottlenecks early - Network request count and transfer size — keep payload bloat in check - JSON snapshot export — baseline today, compare tomorrow LOCALHOST-FIRST WORKFLOW - Auto-restores HUD on localhost after refresh, hot reload, or navigation - Works seamlessly across dev servers — Vite, Webpack, Next.js, Nuxt, and more - Always-visible overlay means no switching to DevTools mid-development - Use on staging, preview deploys, or any live page with one click DEVELOPER-FRIENDLY - Shadow DOM isolation — won't break your app's styles or framework reactivity - Draggable, collapsible HUD with position memory - Dark and light theme with system preference support - Minimal permissions — activeTab + scripting only, no <all_urls> - Zero runtime dependencies — all metrics use native browser APIs HOW IT WORKS 1. Click the DevPulse icon in your toolbar 2. The performance HUD appears on the current page 3. Drag it anywhere, collapse it, switch themes 4. On localhost it stays active across reloads — on other pages, toggle with one click PRIVACY DevPulse runs entirely in your browser. No data is collected, transmitted, or stored on any server. Performance metrics never leave your machine.