React Developer Tools

Why React DevTools?

React applications are notoriously hard to debug with standard browser tools because the virtual DOM abstracts away component structure. React DevTools bridges this gap by providing a dedicated "Components" and "Profiler" tab in Chrome DevTools.

• Inspect live component tree — see parent-child relationships and nesting depth
• Edit props and state in real-time — test edge cases without changing code
• Debug hooks — inspect useState, useEffect, useContext, and custom hooks
• Profile render performance — identify slow components and unnecessary re-renders
• Time-travel debugging — record and replay component state changes

For React developers building complex SPAs, React DevTools is the difference between guessing why a component isn't updating and knowing exactly which prop or state value is the culprit.

Key Features

Setup Guide for React Developers

Step 1: Install the Extension

1. Visit the Chrome Web Store
2. Click "Add to Chrome"
3. The extension installs automatically (no configuration needed)
4. React DevTools icon appears in your browser toolbar
5. Icon turns blue when visiting a React app, gray otherwise

Step 2: Open React DevTools

Access React-specific debugging tabs:

1. Navigate to any React application (e.g., your localhost:3000 dev server)
2. Open Chrome DevTools (F12 or Right-click → Inspect)
3. Look for two new tabs: "⚛️ Components" and "⚛️ Profiler"
4. If tabs don't appear, ensure:
   • The site is actually using React (icon should be blue)
   • You're using React 16.0+ (DevTools doesn't support older versions)
   • Production builds may hide React DevTools — use development mode

Step 3: Inspect Components

Navigate the component tree and inspect props/state:

1. Click the "Components" tab
2. You'll see a tree view of all React components (looks like your JSX structure)
3. Click any component name (e.g., <UserProfile>)
4. Right panel shows:
   • Props: All props passed to the component
   • Hooks: useState, useEffect, useContext values
   • Rendered by: Parent component
   • Source: File path and line number
5. Expand nested objects to see deep property values

Step 4: Edit State in Real-Time

Test edge cases without restarting the app:

1. Select a component with state (e.g., useState hook)
2. In the right panel, find the "Hooks" section
3. Click on a State value (e.g., count: 5)
4. Type a new value (e.g., 9999) and press Enter
5. The UI updates immediately — component re-renders with new state
6. Perfect for testing form validation, loading states, empty arrays, etc.

Step 5: Profile Performance

Identify slow components and unnecessary re-renders:

1. Click the "Profiler" tab
2. Click the "Record" button (blue circle)
3. Interact with your app (click buttons, type in forms, navigate routes)
4. Click "Stop" to finish recording
5. View results:
   • Flamegraph: Visual representation of render times (wider = slower)
   • Ranked: List of components sorted by render duration
   • Component chart: Timeline of when each component rendered
6. Identify components with yellow/red bars (slow renders)
7. Look for components that render unnecessarily (React.memo candidates)

Advanced Debugging Techniques

1. Debugging useEffect Dependencies

Find out why useEffect is re-running unexpectedly:

• Select component with useEffect
• Expand the "Effect" hook in right panel
• See dependency array values (e.g., [userId, currentPage])
• Compare before/after values to identify which dependency changed
• Common culprits: object/array references changing on every render

2. Inspecting Context Values

Debug context providers and consumers:

• Select component using useContext
• See "Context" section with current context value
• Click "Context" to jump to the Provider component
• Verify context value matches expectations
• Useful for debugging authentication state, theme, language, etc.

3. Finding Component Source Code

Jump directly to component definition:

• Select any component in the tree
• Look for "<> View source" link in right panel
• Click to open the exact file and line in Chrome's Sources tab
• Set breakpoints and debug with standard Chrome DevTools

4. Highlighting Updates

Visualize which components re-render:

• Click the "⚙️ Settings" icon in Components tab
• Enable "Highlight updates when components render"
• Interact with your app
• Components flash colored borders when they re-render
• Green = normal, yellow = medium, red = slow renders
• Identify components re-rendering too frequently (optimization opportunities)

React DevTools vs Alternatives

Feature	React DevTools	Redux DevTools	Vue DevTools
Framework	React	Redux (any framework)	Vue.js
Component Tree	✅ Full tree with hooks	❌ No component inspection	✅ Vue components
Props/State Editing	✅ Live editing	⚠️ State only	✅ Live editing
Performance Profiling	✅ Advanced flamegraph	❌ No profiling	✅ Basic profiling
Hooks Debugging	✅ All hooks visible	❌ N/A	✅ Composition API
Time-Travel	⚠️ Limited (Profiler)	✅ Full time-travel	⚠️ Limited
Use Case	React debugging	State management debugging	Vue.js debugging

Verdict: React DevTools is essential for React developers. Redux DevTools is complementary (for state management debugging). If you use both React + Redux, install both extensions.

Common Use Cases

1. Debugging "Component Not Updating"

When a component doesn't re-render after state change:

• Select the component in DevTools
• Check if props/state values are actually changing
• Look for object/array mutations (React requires new references)
• Verify parent component is re-rendering (highlight updates feature)

2. Finding Performance Bottlenecks

When your app feels slow:

• Run Profiler during slow interaction
• Sort by render duration (Ranked view)
• Identify components taking >16ms (causes frame drops)
• Wrap expensive components in React.memo()
• Use useMemo/useCallback for expensive calculations

3. Debugging Props Drilling

When props aren't reaching deeply nested components:

• Select the component that should receive props
• Check props panel — is the prop there?
• If missing, click "Rendered by" to jump to parent
• Trace back through component tree to find where prop is lost
• Common issue: typo in prop name or missing spread operator

Frequently Asked Questions

Why don't I see the Components tab?

The Components tab only appears on websites using React 16.0+. Check if: (1) the site is built with React, (2) you're using a development build (not production), (3) you've refreshed the page after installing the extension.

Can I use React DevTools on production sites?

Yes, but production React builds hide some debugging features. For full functionality, use development builds (npm start instead of npm run build).

Does editing state in DevTools persist?

No, state changes in DevTools are temporary and reset on page refresh. Use it for testing, not permanent changes.

How do I debug components in StrictMode?

React StrictMode causes double-rendering in development. React DevTools shows both renders. This is normal behavior and won't happen in production.

Can I use this with React Native?

Yes! Install the standalone React DevTools app (npm install -g react-devtools) and connect it to your React Native app via react-devtools command.

Why is the Profiler showing different times than console.log?

Profiler measures React render time (virtual DOM), not DOM painting. Use Chrome's Performance tab to measure total paint time.

Related Extensions

Boost your React development workflow with these complementary tools:

• Dark Reader — Reduce eye strain during long debugging sessions
• ColorZilla — Extract exact colors from React components
• Wappalyzer — Detect which React version and libraries a site uses

Get Started Today

Install React Developer Tools now and debug React applications with surgical precision. Join 3 million developers who rely on the official tooling from Meta.