React Developer Tools is a debugging and performance-analysis tool used by React developers to inspect components, examine props and state, understand component hierarchies, and identify rendering performance issues. It is available as a browser extension for popular browsers, including Chrome, Firefox, and Edge.
Official Documentation: React Developer Tools – Official Guide
React Developer Tools, commonly called React DevTools, is a development utility that helps developers understand how a React application works internally. It provides a visual representation of the React component tree and allows developers to inspect the data used by components.
For example, if a button is not displaying the expected value, React DevTools can help you inspect the component, check its props and state, and investigate why the interface is not behaving as expected.
React applications are built using reusable components. As applications grow, understanding how components communicate and update can become difficult. React DevTools helps developers investigate these issues without manually tracing every component in the source code.
| Problem | How React DevTools Helps |
|---|---|
| Unexpected text or values | Inspect props and state to identify the values received by a component. |
| Component not updating as expected | Inspect its current data and investigate state or prop changes. |
| Confusing component structure | View the component hierarchy in the Components panel. |
| Slow user interface | Use the Profiler and browser performance tools to investigate rendering costs. |
| Incorrect parent-child data flow | Inspect component relationships and the props passed between components. |
Choose the extension store for the browser you use.
Open the extension page and select the browser's installation option, such as Add to Chrome or Add to Firefox. Follow any confirmation prompts.
If you already have a React project created with Vite, open its folder in your terminal and run:
npm run devOpen the local URL shown in your terminal, commonly http://localhost:5173.
F12 or Ctrl + Shift + I on Windows.Important: These tabs appear when the extension detects a compatible React application. If they are missing, confirm that the extension is enabled and that the page is running React.
The Components panel displays the React component tree. It helps developers understand how components are arranged and which components render other components.
App
├── Header
├── MainContent
│ ├── UserProfile
│ └── ProductList
│ ├── ProductCard
│ └── ProductCard
└── FooterIn this example, App is the parent component. It renders Header, MainContent, and Footer. The ProductList component renders two instances of ProductCard.
Props are inputs passed from a parent component to a child component. React DevTools helps you inspect the props received by a component at runtime.
function Welcome(props) {
return <h2>Hello, {props.name}!</h2>;
}
function App() {
return <Welcome name="Rahul" />;
}
export default App;In this example, the Welcome component receives the name prop with the value "Rahul".
Welcome component in the tree.name has the expected value.Why is this useful? If the page displays an unexpected name, inspecting props can help determine whether the parent passed the wrong value.
Note: Props are intended to be read-only by the receiving component. Some DevTools versions provide controls for testing values interactively, but changing a value in DevTools is not a substitute for correcting the application's source code.
State represents data managed by a component that can change over time. When state changes, React may render the component again to update the user interface.
import { useState } from "react";
function Counter() {
const [count, setCount] = useState(0);
return (
<div>
<h2>Count: {count}</h2>
<button onClick={() => setCount(count + 1)}>
Increase
</button>
</div>
);
}
export default Counter;Counter component.Initially, count is 0. After clicking Increase once, it becomes 1. React DevTools can help you observe the value associated with the component.
Important: Do not directly mutate state in application code. Use the appropriate state setter, such as setCount, so React can process the update correctly.
Hooks are functions that let function components use React features such as state, context, and effects. React DevTools can show Hook information for supported components.
| Hook | Purpose | What to Investigate |
|---|---|---|
useState |
Stores component state. | Whether the current state value is correct. |
useEffect |
Synchronizes a component with external systems. | Effect dependencies and related state or props. |
useContext |
Reads values from React context. | Whether the component receives the expected context value. |
useReducer |
Manages state through a reducer function. | The current reducer-managed state. |
| Custom Hooks | Reuse stateful logic across components. | Values exposed by the custom Hook, when available. |
Hook visibility and the exact layout of the details panel can vary by React DevTools version and component type.
The Profiler helps developers investigate how React components render and how much time rendering takes. It is useful when a page feels slow or when a component appears to render more often than expected.
Remember: A component rendering again is not automatically a performance problem. First measure the behaviour, identify the cause, and then optimize only where needed.
For more information, read the official React Profiler documentation.
React DevTools is especially useful when a component receives unexpected data, displays the wrong UI, or behaves differently from what you expect.
function UserProfile({ name }) {
return <h2>User: {name}</h2>;
}
function App() {
return <UserProfile name="Amit" />;
}If the displayed name is incorrect, follow these steps:
UserProfile component.name prop.| Feature | React Developer Tools | Browser Developer Tools |
|---|---|---|
| Main purpose | Inspect React components and rendering. | Inspect and debug the browser page, network, JavaScript, and DOM. |
| Component tree | Shows the React component hierarchy. | Elements panel shows the DOM tree. |
| Props and Hooks | Designed to inspect React-specific data. | Does not provide the same React-focused component view by default. |
| Network requests | Not its primary purpose. | Network panel helps inspect requests and responses. |
| JavaScript errors | May help identify component-related issues. | Console and Sources panels help investigate errors and execution. |
| Performance | Profiler provides React rendering information. | Performance panel helps analyze broader browser performance. |
Both tools complement each other. Use React DevTools for React-specific inspection and browser DevTools for DOM, network, JavaScript, and general browser debugging.
| Problem | Possible Solution |
|---|---|
| Components tab is missing. | Confirm that the extension is installed and enabled, then reload a page running a compatible React application. |
| Component tree is empty. | Check whether React is running on the page, whether the correct browser tab is open, and whether the extension can detect the React renderer. |
| Props appear incorrect. | Inspect the parent component and verify the values passed to the child. |
| State does not update as expected. | Review the state setter, event handler, and any related asynchronous logic. |
| The application feels slow. | Record a profiling session and use the browser Performance panel when broader performance information is needed. |
| DevTools does not connect to a special environment. | Check the React DevTools documentation for supported setup options for that environment. |
Objective: Create a small React counter and use React Developer Tools to inspect its component, state, and rendering behaviour.
import { useState } from "react";
function Counter() {
const [count, setCount] = useState(0);
return (
<section>
<h1>React Counter</h1>
<p>Current count: {count}</p>
<button onClick={() => setCount(count + 1)}>
Increase
</button>
<button onClick={() => setCount(0)}>
Reset
</button>
</section>
);
}
export default Counter;Counter from your application's main component.Counter.You should be able to see the Counter component in the component tree and observe its state changing as you interact with the buttons. This exercise demonstrates how React DevTools helps developers understand component behaviour at runtime.
React Developer Tools is a debugging utility that helps developers inspect React components, props, state, Hooks, and rendering performance.
The primary panels are Components and Profiler. Additional panels or capabilities may vary by version and environment.
It displays the React component hierarchy and helps inspect a selected component's props, state, and Hooks.
It records React rendering activity and helps developers investigate component rendering costs and performance problems.
Yes. Selecting a component lets you inspect the props it receives.
Yes. It can show state information for supported components, including state managed through Hooks.
No. React DevTools focuses on React components and rendering, while browser DevTools also provides tools for the DOM, JavaScript, network requests, and general performance.
No. Re-rendering is a normal part of React. Developers should investigate whether the rendering is incorrect or unnecessarily expensive before optimizing it.
The extension may be missing or disabled, the page may not be running a compatible React application, or the development environment may require additional setup.
Yes. It helps beginners understand component relationships, props, state, and how user interactions affect the interface.
React Developer Tools is an essential utility for learning, debugging, and maintaining React applications. Its Components panel helps developers inspect the component hierarchy and runtime data, while its Profiler supports investigation of rendering performance. Learning to use these tools makes it easier to understand React applications and diagnose problems efficiently.
To learn React JS in a structured way, explore the course and demo links below.
JustAcademy React JS Training Course
Register for React JS Course Demo
Additional Learning Resource: Official React Developer Tools Documentation
