Best Free Browser DevTools Extensions in 2026

BY TOOLS.FUN · MARCH 28, 2026 · 4 min read

Browser DevTools extensions turn Chrome and Firefox into powerful development environments. From framework-specific debuggers to performance auditors and accessibility checkers, these free extensions belong in every web developer's toolkit.

React DevTools — Component Tree Inspector

React DevTools adds two panels to your browser DevTools: Components (inspect the React component tree, view props, state, and hooks) and Profiler (measure render performance and identify unnecessary re-renders). You can edit props and state live, search for components by name, and trace which components caused a re-render. For React developers, this extension is as essential as the Elements panel. It supports React 16+ including concurrent features and server components.

Best for: React developers debugging component state, props, and render performance.

Vue DevTools — Vue-Specific Debugging

Vue DevTools provides a component inspector, Vuex/Pinia state management viewer, router debugger, and performance timeline for Vue applications. The Vue 3 version includes a component graph visualization and an events timeline. You can edit component data live, time-travel through Vuex mutations, and inspect route matching. Like React DevTools, it's indispensable for Vue development — the component tree view alone saves hours of console.log debugging.

Tip: When inspecting API responses in React or Vue DevTools state panels, copy the JSON data and paste it into our JSON Formatter for a cleaner, more readable view of deeply nested objects.

Lighthouse — Performance & SEO Auditing

Lighthouse (built into Chrome DevTools) audits web pages for performance, accessibility, best practices, SEO, and Progressive Web App compliance. Each category produces a score (0-100) with specific, actionable recommendations. Performance metrics include First Contentful Paint, Largest Contentful Paint, Total Blocking Time, and Cumulative Layout Shift. Run Lighthouse on every page before launch — it catches issues that manual testing misses, from missing meta tags to render-blocking resources.

axe DevTools — Accessibility Testing

axe (by Deque) scans your page for accessibility violations against WCAG 2.1 guidelines. It identifies missing alt text, insufficient color contrast, missing form labels, improper ARIA usage, keyboard navigation issues, and more. Each violation includes the impact level, affected elements, and specific fix guidance. The free browser extension provides full scanning capability. Run axe alongside Lighthouse — Lighthouse's accessibility audit uses axe rules, but the standalone axe extension provides more detailed results and better issue navigation.

Redux DevTools — State Management Debugger

Redux DevTools provides time-travel debugging for Redux stores: inspect every dispatched action, view the state diff, and jump to any previous state. It supports action replay, state import/export, and custom action dispatching. Even if you're using Redux Toolkit, Zustand (with middleware), or other Redux-compatible stores, this extension provides invaluable debugging capabilities. The action log makes it trivial to trace exactly how state changed in response to user interactions.

Tip: Export your Redux state snapshots and format them with our JSON Formatter for sharing with teammates when reporting bugs. A formatted state snapshot is worth a thousand words in a bug report.

Essential Extension Stack

Every web developer should install: React or Vue DevTools (framework-specific), Lighthouse (built-in, just use it), axe (accessibility), and Redux DevTools (if using Redux/compatible state management). These four extensions, combined with Chrome's built-in Network, Performance, and Elements panels, give you a complete frontend debugging and auditing toolkit — all free, all essential.

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