Best browser extensions for web developers

React Developer Tools is the official debugger for React apps. It adds a Components tab to your browser's DevTools, so you can see the tree of components behind a page instead of the flat HTML. Select one and you can read its props, state and instance details, and search the tree by component name.

The extension is built from the React repository, which is MIT licensed, and the Chrome build runs on Manifest V3. It was updated in September 2026, and the Chrome store listing now shows the React Foundation as the developer. It works in Chrome, Firefox and Edge. For Safari and other browsers there is no extension, but the same project ships a standalone react-devtools app that connects through a script tag, and React Native has a built-in debugger that integrates it.

The trade-offs are modest. The tabs appear only on pages built with React. Its Chrome rating of 3.5 out of 5 is lower than the other framework tools. It also asks for access to every site so it can detect React. For anyone writing React, installing it is an easy decision, and it is the obvious first pick for this category.

Vue.js devtools is the official debugging extension for Vue, maintained in the Vue project's own repository. It adds a Vue panel to your browser's DevTools for inspecting the components in a running app. The code is MIT licensed, and the project's documentation describes a second route: installing the same tooling as a Vite plugin, which works in any browser.

The version question matters. The documentation says version 7 and later supports Vue 3 only. For Vue 2 apps it links to the older version 6 and version 5 listings in the Chrome Web Store. The repository is busy, with version 9 pre-releases published in October 2026, but the main Chrome listing still shows version 7.7.7 from June 2025 and a rating of 2.1 out of 5. On Edge, the Vue docs send you to the Chrome listing rather than a separate store page. Firefox has its own listing, updated in June 2025.

The extension needs access to all websites so it can detect Vue on whatever page you open. That is the usual price of a framework debugger. If you work with Vue 3, install it. If you are on Vue 2, use the version 6 listing, and expect an older tool.

Redux DevTools shows what your app's state is doing. Each action you dispatch appears in a log with the state that resulted, and Mozilla's listing says you can inspect every state and action payload and go back in time by cancelling actions. It is built by the Redux team and lives in the reduxjs organisation on GitHub.

Unlike the other framework tools it does not detect your app automatically. Your code has to connect to it, usually by passing a small enhancer when you create the store. The README documents this for Redux, and links to integrations for other architectures and for non-browser apps, plus options to limit it in production. The code is MIT licensed, the Chrome build runs on Manifest V3, and the latest release came out in October 2026.

The cost is the setup and a dense interface, and its host access covers all websites, plus a notification and context menu permission. If you build with Redux, or with a library that supports the same connection, it is one of the most useful debugging tools available, and well worth the few minutes of configuration.

JSONView does one job: when you open a JSON document in a tab, it shows the data formatted, colour-highlighted and collapsible instead of as one long line. It is made by Benjamin Hollis, who has run the project in public for years, and the source on GitHub is MIT licensed. The author says the goal is to stay simple and rejects features that add complexity.

That restraint is the reason to pick it. JSON viewers have a mixed trust record: in 2026 the widely installed JSON Formatter added a donation prompt and its author announced a closed-source model, before saying in September that it would stay open source. JSONView has no such history in anything we found. The Chrome build is Manifest V3, last updated in May 2025, and Firefox, Edge and Chrome versions all exist. If the JSON has errors, it still shows the raw text.

It needs permission to read the pages you open and to see web requests, so it can detect JSON responses. The download is free and the author states there is no Safari version, because publishing one costs money. For plain viewing it is the safest default, with no extra features to second-guess.

Requestly lets you intercept web traffic from inside the browser and change it: rewrite headers, redirect URLs, block requests, inject scripts or return mock responses for REST and GraphQL calls. The Chrome listing describes exactly that set, and it needs no proxy. For years this territory belonged to ModHeader, which is the reason to look at Requestly now.

ModHeader was pulled from the Chrome and Edge stores in July 2026 after researchers found a dormant browsing-history collector in the genuine extension. Requestly is a different case. Its HTTP Interceptor code is public on GitHub, mostly under the AGPL, the extension runs on Manifest V3, and the Chrome version was updated at the end of September 2026. BrowserStack, which acquired Requestly in May 2025, states in its privacy policy that Requestly does not sell personal data.

There are trade-offs. Requestly is a commercial product: the Chrome listing notes in-app purchases and Requestly's site sells paid team plans, so check what the free extension includes. The privacy policy is written for the whole company, not the extension, and it mentions analytics and sharing of combined data for promotional purposes. It also needs broad site access. It is the one we would use for request rewriting.

Accessibility Insights for Web is Microsoft's free tool for finding accessibility problems in web pages. It runs two main routines. FastPass is a quick check of common, high-impact issues, with a tab-stops review for keyboard problems such as traps and a wrong tab order. Assessment is the thorough one, testing against WCAG 2.1 Level AA with around 50 automated checks and roughly 20 guided manual tests.

It is built on axe-core, the same engine behind Deque's tools, and the whole project is MIT licensed on GitHub. The Chrome version runs on Manifest V3 and was updated in September 2026, and an Edge listing is published by Microsoft. Telemetry is opt-in: the documentation says anonymised usage and crash data are collected only with consent, and you can switch it off at any time.

The main limitation is browser coverage. It is available for Chrome and Edge, with no Firefox or Safari version, and note that a similarly named Firefox listing is not from Microsoft. Deque's axe DevTools is an alternative with a free version, but its Chrome rating is lower, at 3.2 out of 5. If you want a free, transparent accessibility checker you can use to learn as well as to test, this is the one to pick.

Web Developer is a toolbar button that opens a menu of small utilities for people who build websites. It is made by Chris Pederick, an individual developer, and it has been around for many years. The extension is available for Chrome, Edge, Firefox and Opera, and the source on GitHub is released under the GNU GPL.

The appeal is breadth. Rather than a single focused feature, it collects many everyday tools in one place, and its permissions give a hint of what they touch: cookies, history, browsing data, scripting and tabs. We have not reviewed the full feature list, so check the author's home page for specifics. The Chrome build is Manifest V3. Chrome rates it 4.3 out of 5 from around a million users.

There are two things to know. The last release, version 3.0.1, dates from June 2024, so it is stable rather than actively developed. And those permissions are broad, especially cookie and browsing-data access, which fits the tool but is a lot of trust. It comes from a named author with no incidents we could find. If you want one general toolbar rather than several single-purpose extensions, it remains a reasonable choice.

Angular DevTools is the Angular team's own browser extension for debugging and profiling Angular apps. Its documentation lists a component explorer where you can preview and edit state, a profiler for finding change-detection bottlenecks, and tree views of the injector hierarchy and the router. Some experimental tabs can be switched on in its settings.

It lives in the main Angular repository under the MIT licence. The Chrome build is Manifest V3 and was updated in October 2026, and the Firefox add-on was updated the same week. The documentation names Chrome and Firefox as the supported browsers, and it adds that Chromium-based browsers also get a Performance panel integration. The Chrome listing has about 300,000 users and a rating of 3.0 out of 5, which is low for an official tool.

It only works on development builds. To debug a deployed app, the documentation says to use ng serve or disable build optimisation. The extension asks for access to all websites so it can detect Angular, along with active tab, storage and debugger permissions. We left it at the bottom of the ranking only because fewer developers need it than the others. If you write Angular, install it.