NextJS: Top 10 Interview Questions & Answers in 2023

Juan SalasJuan Salas

Juan Salas

NextJS: Top 15 Interview Questions & Answers

NextJS is a highly recommended React framework for building server-side rendered applications. It offers a wide range of features and several benefits, making it a great choice for developers looking to build high-performing web applications.

With the growing popularity of Next, developers need to be well-versed in the framework, and this article aims to help with that.

We have compiled the top 10 interview questions and answers related to NextJS to help you prepare for your “next” interview. These questions cover a wide range of topics, including the basics of NextJS, features, advantages, and limitations.

By going through these questions, you will better understand NextJS and be able to answer any related questions that come up during an interview.

Here are the NextJS Top 10 Interview Questions & Answers in 2023

1. What is NextJS, and what are its benefits?

Next.js is a framework for building server-side rendered (SSR) applications using React. It offers several benefits, including improved performance, automatic code splitting, simplified routing, and easier deployment. Additionally, it provides a great developer experience with features like hot module reloading and zero-configuration development.

Next.js allows developers to create static sites easily and deploy them quickly and inexpensively. This makes it ideal for small projects or personal sites. Furthermore, Next.js is highly extensible, allowing developers to customize the framework to meet their specific needs.

2. What is server-side rendering, and how does it work in NextJS?

Server-side rendering (SSR) is a technique in web development where the server renders the initial HTML and sends it to the client instead of relying on client-side JavaScript to render the page.

In Next, SSR is supported out of the box; when a user requests a page, the server fetches the data and generates the HTML markup on the server, which is then sent to the client. This can improve SEO, Time to First Byte (TTFB), and overall performance.

3. What is static site generation, and how does it differ from server-side rendering?

Static site generation is the process of generating a website's HTML, CSS, and JavaScript files before a client requests them. This means that the content of the website is pre-built and served as static files.

In contrast, server-side rendering generates the HTML on the server, dynamically creating the content each time a request is made. Static site generation is faster since the content is already built and doesn't require server-side processing, while server-side rendering is more flexible, allowing for dynamic content and interactions.

4. What is dynamic routing and how is it implemented in NextJS?

Dynamic routing is a web application’s ability to serve different pages to the user based on the URL requested.

In NextJS, dynamic routing can be implemented using the file system. Pages can be created using brackets in the file name, which will then be used as parameters in the URL.

For example, creating a page named [id].js will allow for dynamic routing based on the id parameter in the URL.

5. How do you handle data fetching in NextJS?

In NextJS, you can use the built-in getStaticProps or getServerSideProps functions to fetch data from an external API or database. getStaticProps fetches data at build time and returns it as props to the page, while getServerSideProps fetches data on each request.

You can also use client-side data fetching libraries like axios or fetch in combination with useEffect or useState hooks.

6. What are the different options for styling NextJS apps?

There are different options for styling NextJS apps, including CSS modules, CSS-in-JS libraries such as styled-components or emotion, and global CSS files.

  • CSS modules in Next allow you to write modular CSS that only applies to specific components. This helps avoid naming collisions and keeps your CSS organized.
  • CSS-in-JS libraries like styled-components or emotion provide a way to write CSS directly in your JavaScript code, which can make it easier to manage the styles for a specific component.
  • Global CSS files can be used to apply styles to your entire application.

Each approach has its own advantages and disadvantages, and the best choice depends on the specific needs of your application.

It's important to consider factors such as performance, maintainability, and developer familiarity when choosing a styling approach for NextJS apps.

7. How do you deploy a NextJS app?

To deploy a NextJS app, you first need to run the command "next build" which will create a production-ready version of your app in a .next folder.

You can then use various hosting services, such as Vercel, Netlify, or AWS, to deploy your app to a production environment by uploading the contents of the .next folder to your server.

Always remember to set the environment variables needed for your app to run properly in the chosen hosting service.

8. What are some best practices for optimizing NextJS app performance?

  • Keep your Next.js bundle light.
  • Implement server-side rendering (SSR) for dynamic content.
  • Utilize the "getStaticProps" method to pre-generate data for static content pages.
  • Employ the "getServerSideProps" method to pre-generate data for dynamic content pages.
  • Leverage dynamic imports to divide large code chunks and load them as needed. Incorporate the "Image" component from NextJS for optimized image loading.
  • Utilize the "shouldComponentUpdate" lifecycle method or React.memo to minimize unnecessary re-renders.

9. What are some testing and debugging tools available for NextJS apps?

Several testing and debugging tools are available for NextJS apps, including:

  • Jest (for unit testing)
  • Cypress (for end-to-end testing)
  • React Testing Library (for testing React components)
  • Next.js built-in debugger (for debugging server-side rendering issues)

10. How do you work with custom server middleware in NextJS?

Custom server middleware can be added in NextJS by creating a Node.js server and using the use method of the server object to add middleware to it. This can be done in the server.js file, located in the root directory of the NextJS app.

Middleware functions can be added using the app.use method and can be used to modify incoming requests and outgoing responses.


We hope that this article has provided valuable insights for developers looking to improve their NextJS skills and ace their interviews.

It is important to note that the interview questions and answers presented in this article are not exhaustive, and there may be additional topics and questions that interviewers may ask.

However, going through these questions will provide you with a solid foundation and understanding of NextJS, which will help you to prepare for interviews and build better applications.