Alternatives to Discontinued Web Vitals

Official browser extension by Meta for inspecting and debugging React component trees, props, state, hooks, and context in real-time. Features component highlighting on hover, profiler for measuring render performance and identifying bottlenecks, and component search/filtering. Supports React 16+ including Suspense, error boundaries, and concurrent features. Available for Chrome and Firefox. Essential for debugging re-renders, state management issues, and understanding component hierarchies.

Official browser DevTools extension for Vue.js providing deep inspection of component trees, reactive state, props, events, and slots. Includes Pinia/Vuex store debugging with time-travel, Vue Router inspection, performance timeline, and component highlighting. Works with Vue 2 and Vue 3. Available for Chrome and Firefox with standalone Electron app. Essential for debugging reactivity and understanding component hierarchies in Vue applications.

Open-source browser for responsive web development that shows multiple device viewports simultaneously with synchronized scrolling, clicking, and navigation. Preview your site on phone, tablet, and desktop sizes side by side in real-time. Features screenshot capture for all viewports, element inspector, network monitoring, and hot-reload support. Built on Chromium. Free alternative to Polypane for developers who need quick responsive testing without paid subscriptions. 23K+ GitHub stars.