Developer Browser Extensions Guide

BY TOOLS.FUN · MAY 21, 2026 · 4 min read

The right browser extensions transform your development workflow. From auto-formatting JSON responses to inspecting component trees, these tools save hours of manual work every week. Here are the extensions every web developer should consider installing.

JSON Viewer Extensions

When you navigate to an API endpoint in your browser, the raw JSON is a wall of unformatted text. A JSON viewer extension automatically detects JSON responses and formats them with syntax highlighting, collapsible nodes, and clickable links. Popular options include JSONVue (Chrome), JSON Formatter (Chrome), and JSONView (Firefox).

The best JSON viewers also let you filter and search within the formatted output, copy paths to specific values, and toggle between formatted and raw views. For quick API exploration, this is faster than copying the response into the JSON Formatter, though tools.fun provides more features for complex formatting tasks.

React and Vue DevTools

If you work with React or Vue, their official DevTools extensions are essential. React DevTools adds a Components tab showing the component tree, props, state, hooks, and context. Vue DevTools provides the component inspector, Vuex/Pinia state, event timeline, and performance profiling.

These extensions let you modify component state in real time to test edge cases, inspect prop drilling issues, profile render performance, and understand component hierarchies in unfamiliar codebases. Install the one matching your framework — they have zero overhead when inactive.

Performance tip: Use the React Profiler (in the DevTools extension's Profiler tab) to identify unnecessary re-renders. Record a user interaction, then inspect which components re-rendered and why. Components that re-render without visible changes are optimization candidates.

Wappalyzer — Identify Tech Stacks

Wappalyzer detects the technologies used by any website you visit — frameworks (React, Next.js, WordPress), analytics tools (Google Analytics, Plausible), CDNs (Cloudflare, Fastly), and hosting providers. Click the extension icon on any site to see its full tech stack.

This is invaluable for competitive research, understanding how sites you admire are built, and verifying that your own deployments use the expected technology. Wappalyzer's detection is fingerprint-based (HTTP headers, script patterns, meta tags), so it works without accessing source code.

uBlock Origin — The Essential Ad Blocker

uBlock Origin is not just an ad blocker — it is a wide-spectrum content blocker that improves page load times, reduces bandwidth usage, and blocks tracking scripts. For developers, the benefits go beyond comfort: it prevents ad scripts from interfering with debugging, eliminates layout shifts caused by ad loading, and reduces noise in the Network tab.

The "element picker" mode lets you create custom rules to hide specific page elements — useful for removing cookie banners, notification popups, and other distractions during development. Be sure to disable it occasionally to test your own sites as real users see them.

Other Essential Extensions

ColorZilla: An eyedropper and colour picker that works on any page. Click to get the exact colour of any pixel, including computed colours from gradients and overlays. Pair with the Color Converter for format conversion.

Lighthouse: Google's built-in performance, accessibility, and SEO auditing tool. Run it on any page to get scored recommendations. Available in DevTools by default, but the extension provides quick access.

EditThisCookie: View, edit, add, and delete cookies for the current site. Essential for debugging authentication, session management, and cookie-based features.

Responsive Viewer: Shows your page rendered at multiple device sizes simultaneously. Faster than resizing the browser window or toggling DevTools device mode for each size.

Extension hygiene: Every extension has access to your browsing data to some degree. Audit your extensions quarterly — remove anything you do not actively use, and check permissions. Prefer open-source extensions that have been publicly reviewed. Keep extensions updated, as security patches are frequent.

Managing Extension Overload

Too many extensions slow your browser and create toolbar clutter. Use Chrome profiles or Firefox containers to separate your development extensions from personal browsing. Create a "dev" profile with all your development extensions and a "clean" profile with none — the clean profile is useful for testing how your site behaves without extensions interfering.

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