Next.js interview questions asked in 2025

If you’re preparing for your next tech interview, these Next.js interview questions and answers will help you master core concepts like SSR, SSG, API routes, and more.

Next.js Interview Questions: 10 Most Common in 2025

Why Learn Next.js?

1. What is Next.js?
   • Answer: Next.js is an open-source JavaScript framework used for building server-rendered React applications. It provides features like server-side rendering, static site generation, routing, and more, to create efficient and high-performance web applications.
2. What are the benefits of using Next.js?
   • Answer: Next.js offers benefits such as improved performance through server-side rendering and automatic code splitting, better SEO due to server-rendered content, simpler routing, and support for static site generation for faster loading times.
3. How does server-side rendering (SSR) work in Next.js?
   • Answer: Next.js performs server-side rendering by rendering React components on the server before sending them to the client. This means that when a user requests a page, they receive a fully rendered HTML page rather than just JavaScript, which can lead to faster initial page loads and better SEO.
4. What is static site generation (SSG) in Next.js?
   • Answer: Static site generation in Next.js involves generating static HTML files at build time for pages that do not require dynamic data. This can significantly improve website performance by delivering pre-rendered content to users.
5. How can you create dynamic routes in Next.js?
   • Answer: Next.js allows you to create dynamic routes by using the [slug].js file naming convention. For example, if you want to create dynamic blog post pages, you can create a file named [slug].js inside the pages directory and use the getStaticPaths and getStaticProps functions to fetch and render data.

Most Asked Next.js Interview Questions

1. Explain the purpose of API Routes in Next.js.
   • Answer: API Routes in Next.js allow you to create serverless API endpoints directly within your application. This is useful for handling backend functionality and API calls without the need for a separate server.
2. How do you handle CSS and styling in Next.js?
   • Answer: Next.js provides various options for handling CSS and styling, including CSS modules, global styles, and support for third-party libraries like styled-components. CSS modules allow you to scope styles to specific components, preventing global style conflicts.
3. What is the role of the getInitialProps function in Next.js?
   • Answer: getInitialProps is a special function you can use in a page component to fetch data before rendering the page. It’s often used for server-side rendering or data fetching in traditional client-side routing.
4. How can you optimize the performance of a Next.js application?
   • Answer: Performance optimization in Next.js can be achieved through techniques like code splitting, lazy loading, utilizing server-side rendering and static site generation, optimizing images, and reducing unnecessary rendering.
5. What is the purpose of the _app.js file in Next.js?
   • Answer: The _app.js file is a special file in Next.js that allows you to customize the wrapper component that surrounds all pages. It’s useful for adding global styles, state management, and other common functionality.

Remember, these answers are meant to provide a general overview. It’s a good idea questions during your interview .

Conclusion:

Mastering these Next.js interview questions will help you succeed in your next job interview.