What is Next.js? A Guide to React Development with Server-side Rendering and Code Splitting

Unlock Lightning Speed and SEO Superpowers for Your React Apps with Next.js


7 min read

What is Next.js? A Guide to React Development with Server-side Rendering and Code Splitting


Next.js is a powerful React-based framework that has gained popularity among developers due to its ability to simplify server-side rendering and automatic code splitting for faster web application development.

In the first part of the Next JS series, we will explore what Next.js is, its history, applications, key features, and future trends. By the end of this guide, you will have a comprehensive understanding of how Next.js can help you build scalable and performant web applications with ease.

Server-side Rendering

Server-side rendering (SSR) is a technique that enables web pages to be rendered on the server before being sent to the client's browser. This means that instead of relying solely on client-side JavaScript to render the page, the server generates an HTML response that can be displayed immediately. SSR is particularly useful for applications with a lot of dynamic content, as it allows search engines to crawl and index the content more easily.

With Next.js, SSR is built-in and requires no additional configuration. By default, all pages are pre-rendered on the server, ensuring fast load times and improved performance. This means that even if a user has a slow or unreliable internet connection, they will still be able to view your website quickly and efficiently.

Benefits of Server side Rendering with Next.js

One of the key benefits of using Next.js for SSR is improved performance. By rendering pages on the server, you can reduce the amount of work required by the client's browser, resulting in faster load times and a better user experience. Additionally, because search engines can crawl and index your content more easily, you may see an improvement in your SEO rankings.

Another benefit of SSR with Next.js is enhanced user experience. With SSR, users can see a fully rendered page immediately upon loading it, rather than waiting for JavaScript to execute before seeing any content. This can lead to higher engagement rates and lower bounce rates.

  • Improved performance: SSR in Next.js reduces client side processing, leading to faster load times and a better user experience.

  • SEO advantage: SSR enables search engines to crawl and index content easily, potentially boosting SEO rankings.

  • Enhanced user experience: With SSR, users can view fully rendered pages immediately upon loading, increasing engagement rates and reducing bounce rates.

  • Reduced client side work: SSR reduces the burden on the client's browser, resulting in smoother page rendering and interactions.

  • Smooth transitions: When navigating between pages, you get a smooth transition since the HTML is pre-rendered on the server before being sent to the client. There is no visual flash of unstyled content.

Automatic Code Splitting

In traditional web development, all of the JavaScript code for a web application is bundled together into a single file. This can result in slow page load times and poor performance, especially on slower internet connections or older devices. Automatic code splitting is a technique that Next.js uses to break up this single file into smaller chunks, which are loaded only when they are needed.

What is Automatic Code Splitting?

Automatic code splitting is the process of breaking up a large JavaScript bundle into smaller chunks that can be loaded on demand. This means that instead of loading the entire bundle at once, only the necessary parts of the application are loaded as they are needed.

Next.js uses automatic code splitting by default to help improve performance and reduce page load times. When you build your application with Next.js, it automatically splits your code into separate files based on page routes and components. This means that each page of your application only loads the JavaScript code it needs to render that specific page.

Benefits of Automatic Code Splitting with Next.js

The benefits of automatic code splitting with Next.js are significant. By breaking up your JavaScript bundle into smaller chunks, you can:

  • Improve page load times: Because only the necessary parts of your application are loaded as they are needed, pages load faster and users have a better experience.

  • Reduce initial load time: With automatic code splitting, the initial download size of your application is smaller than it would be if you were using traditional bundling techniques.

  • Optimize performance: By reducing the amount of JavaScript that needs to be parsed and executed by the browser, you can optimize performance and improve overall user experience.

  • Increase scalability: As your application grows in complexity, automatic code splitting makes it easier to manage and scale without sacrificing performance.

File-system Routing

Next.js offers a unique feature called file-system routing, which is a powerful tool for organizing pages and routes in your application. With file-system routing, you can create nested folders and files that map directly to routes in your web application. This means that you can organize your codebase in a logical and intuitive way, making it easier to navigate and maintain.

What is File-system Routing?

File-system routing is a technique used by Next.js to simplify the process of defining routes in your web application. Instead of manually defining each route in a separate file or configuration file, file-system routing allows you to define routes based on the structure of your project's folder hierarchy.

For example, if you have a page located at /pages/blog/posts/[slug].js, Next.js will automatically generate a route for that page at /blog/posts/:slug. This makes it easy to create dynamic routes with minimal configuration.

Benefits of File-system Routing with Next.js

  • Simplified route definition: File-system routing in Next.js simplifies the process of organizing and defining routes, making the codebase more intuitive and organized.

  • Improved scalability: As the web application grows and new pages are added, file-system routing makes it easier to manage different routes by creating new files and folders within the project's structure.

  • Enhanced performance: File-system routing optimizes performance by loading only the necessary components for each page when requested, leading to faster page loads and improved overall performance.

Hot Code Reloading

Hot Code Reloading is a feature of Next.js that allows you to see the changes they make to their code in real-time, without having to manually refresh the page. This means that as soon as a developer saves their changes, the page will automatically update with the new code. This can be a huge time-saver for you, as it eliminates the need to constantly switch between their text editor and browser.

Hot Code Reloading works by keeping track of which modules have changed since the last build, and then only updating those modules when a change is detected. This process is much faster than doing a full rebuild of the entire application every time a change is made.

Benefits of Hot Code Reloading with Next.js

  • Faster development time: Hot Code Reloading in Next.js eliminates the need for manual page refreshing, saving you time on repetitive tasks and allowing them to focus on writing code.

  • Improved productivity: Instant feedback on code changes helps you identify and address issues quickly, leading to more efficient development and better code quality.

  • Better user experience: Hot Code Reloading enables faster bug fixes and frequent updates, allowing users to access new features and improvements more rapidly compared to traditional development methods.


Next.js is a powerful framework that enables you to build scalable and performant web applications with ease. Its server-side rendering capabilities, automatic code splitting, file-system routing, and hot code reloading make it an ideal choice for React development.

As we look towards the future of web development, we can anticipate increased adoption of Next.js for building e-commerce websites, continued growth in popularity for building web applications, and more integration with other technologies for enhanced functionality. By leveraging the power of Next.js today, you can optimize their performance and SEO while creating dynamic web applications that meet the demands of tomorrow's users.

Now, I'd love to hear your thoughts and gather any questions or topics you'd like me to address in future articles related to anything React and Web Development. Your input will help me provide more valuable insights and cater to your specific interests.

Also, I tweet my blogs on Twitter. Make sure to follow me to get the latest updates regarding everything Web Development!

Did you find this article valuable?

Support Arjun by becoming a sponsor. Any amount is appreciated!