The latest articles on DEV Community by TechQA (@techqa). https://dev.to/techqa https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3924555%2F9d5e6cbb-f4a4-4430-ad0d-e23e53b5bacb.png https://dev.to/techqa en TechQA Mon, 11 May 2026 09:05:33 +0000 https://dev.to/techqa/top-25-react-interview-questions-and-answers-for-2026-2g5j https://dev.to/techqa/top-25-react-interview-questions-and-answers-for-2026-2g5j <h1> Top 25 React Interview Questions and Answers for 2026 </h1> <p>React is one of the most popular frontend libraries used by companies worldwide. If you're preparing for frontend interviews, these React interview questions will help you revise important concepts quickly.</p> <h2> 1. What is React? </h2> <p>React is a JavaScript library developed by Facebook for building user interfaces using reusable components.</p> <h2> 2. What is Virtual DOM? </h2> <p>Virtual DOM is a lightweight copy of the real DOM. React compares changes in the Virtual DOM and updates only the necessary parts in the real DOM, improving performance.</p> <h2> 3. What are React Components? </h2> <p>Components are reusable building blocks in React that return UI elements.</p> <h3> Types of Components: </h3> <ul> <li>Functional Components</li> <li>Class Components</li> </ul> <h2> 4. What is JSX? </h2> <p>JSX stands for JavaScript XML. It allows developers to write HTML-like syntax inside JavaScript.</p> <p>Example:<br> </p> <div class="highlight js-code-highlight"> <pre class="highlight jsx"><code><span class="kd">function</span> <span class="nf">App</span><span class="p">()</span> <span class="p">{</span> <span class="k">return</span> <span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;</span>Hello React<span class="p">&lt;/</span><span class="nt">h1</span><span class="p">&gt;;</span> <span class="p">}</span> </code></pre> </div> <h2> 5. What is the difference between props and state? </h2> <div class="table-wrapper-paragraph"><table> <thead> <tr> <th>Props</th> <th>State</th> </tr> </thead> <tbody> <tr> <td>Read-only</td> <td>Mutable</td> </tr> <tr> <td>Passed from parent</td> <td>Managed inside component</td> </tr> <tr> <td>Used for communication</td> <td>Used for dynamic data</td> </tr> </tbody> </table></div> <h2> 6. What are Hooks in React? </h2> <p>Hooks allow functional components to use state and lifecycle features.</p> <h3> Popular Hooks: </h3> <ul> <li>useState</li> <li>useEffect</li> <li>useMemo</li> <li>useCallback</li> <li>useRef</li> </ul> <h2> 7. What is useEffect? </h2> <p><code>useEffect</code> is used for side effects like:</p> <ul> <li>API calls</li> <li>Timers</li> <li>Event listeners</li> </ul> <p>Example:<br> </p> <div class="highlight js-code-highlight"> <pre class="highlight jsx"><code><span class="nf">useEffect</span><span class="p">(()</span> <span class="o">=&gt;</span> <span class="p">{</span> <span class="nf">fetchData</span><span class="p">();</span> <span class="p">},</span> <span class="p">[]);</span> </code></pre> </div> <h2> 8. What is State in React? </h2> <p>State stores dynamic data inside a component and causes re-rendering when updated.</p> <p>Example:<br> </p> <div class="highlight js-code-highlight"> <pre class="highlight jsx"><code><span class="kd">const</span> <span class="p">[</span><span class="nx">count</span><span class="p">,</span> <span class="nx">setCount</span><span class="p">]</span> <span class="o">=</span> <span class="nf">useState</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span> </code></pre> </div> <h2> 9. What is Conditional Rendering? </h2> <p>Conditional rendering means displaying UI based on conditions.</p> <p>Example:<br> </p> <div class="highlight js-code-highlight"> <pre class="highlight jsx"><code><span class="p">{</span><span class="nx">isLoggedIn</span> <span class="p">?</span> <span class="p">&lt;</span><span class="nc">Dashboard</span> <span class="p">/&gt;</span> <span class="p">:</span> <span class="p">&lt;</span><span class="nc">Login</span> <span class="p">/&gt;}</span> </code></pre> </div> <h2> 10. What is Key in React Lists? </h2> <p>Keys help React identify changed items efficiently during rendering.</p> <p>Example:<br> </p> <div class="highlight js-code-highlight"> <pre class="highlight jsx"><code><span class="nx">items</span><span class="p">.</span><span class="nf">map</span><span class="p">(</span><span class="nx">item</span> <span class="o">=&gt;</span> <span class="p">(</span> <span class="p">&lt;</span><span class="nt">li</span> <span class="na">key</span><span class="p">=</span><span class="si">{</span><span class="nx">item</span><span class="p">.</span><span class="nx">id</span><span class="si">}</span><span class="p">&gt;</span><span class="si">{</span><span class="nx">item</span><span class="p">.</span><span class="nx">name</span><span class="si">}</span><span class="p">&lt;/</span><span class="nt">li</span><span class="p">&gt;</span> <span class="p">))</span> </code></pre> </div> <h2> Why Learn React in 2026? </h2> <p>React remains highly demanded because:</p> <ul> <li>Huge job market</li> <li>Strong ecosystem</li> <li>Used by startups and enterprises</li> <li>Excellent performance</li> </ul> <h2> Final Thoughts </h2> <p>Preparing React interview questions regularly can improve confidence and technical understanding.</p> <p>You can find more React interview questions, JavaScript interview preparation, Node.js questions, and coding interview resources at:</p> <p><a href="https://techqa.online" rel="noopener noreferrer">https://techqa.online</a></p> <h1> react #javascript #webdev #frontend #career </h1> react webdev javascript