Introduction

Next.js, a popular React framework, has transformed how developers create modern online applications. It includes advanced features like Client-Side Rendering (CSR), Server-Side Rendering (SSR), Static Site Generation (SSG), and Incremental Static Regeneration (ISR) that improve your application's efficiency and user experience.

Server-side rendering (SSR) is a web development technique in which a webpage's content is rendered on the server rather than in the client's browser. In contrast, Static Site Generation (SSG) is a technique for rendering web pages ahead of time during the build phase.

In this article, we'll explore SSG and SSR, the most widely used and crucial rendering methods in Next.js today. We'll explore their fundamental differences, advantages, disadvantages, use cases, and implementations.

Server-Side Rendering (SSR)

Server Side Rendering (SSR) is an application's ability to turn HTML files stored on the server into a fully rendered HTML page for the client. The web browser sends a request for information to the server, which promptly answers by delivering the client a wholly displayed page. Search engines may crawl and index content before it is delivered, which is helpful for SEO purposes. With SSR, all rendering occurs on the server at the request time. The server assembles the fetched data and HTML content for each request before sending it to the client.

SSR is suitable for web pages that display real-time information, updates, or frequently changing content. Examples include the following:

• A real-time chat app that provides the initial page load with user data and chat history.
• A payment app that displays user account details and recent transactions.
• An e-commerce site that offers product pages with dynamic pricing and availability.

How Does SSR Work?

When a user's browser sends a request to the server hosting the content with the user's data attached, it generates a ready HTML file, making it accessible and fully interactive.

Pros of SSR

• Dynamic Content: SSR enables real-time content generation, allowing instant updates and personalized experiences. It's great for applications like news sites, real-time dashboards, and live data platforms requiring up-to-date information.
• SEO-Friendly: SSR provides completely rendered HTML, which is helpful for search engine indexing.
• Flexibility: SSR connects with various back-end services or databases and can handle complex server-side logic.

Cons of SSR

• Performance: Unlike SSG, SSR generates pages for each request, which can lead to slower load speeds. This is especially true when extensive server-side logic is involved, such as heavy computations, complex data fetching, and synchronous operations.
• Scalability: As traffic volume increases, scaling SSR may become more challenging due to its higher demand for server resources.
• Increased Cost: Hosting SSR-based apps is more expensive due to the increased server-side processing and resource requirements.
• Increased Server Load: SSR can elevate server load, necessitating more reliable infrastructure and upkeep.

When is The Best Time to Use SSR?

The best time to utilize SSR is for applications that require frequently updated data, real-time data, or building user-specific content, such as e-commerce sites, dashboards, or social media sites.

SSR is not only advised but necessary in situations where dynamic content and customized interactions are essential. Its role in these scenarios cannot be overstated.

How to implement SSR in Next.js

If we are using the "Page Router" in Next.js, contrary to the "App router" for routing, we have to use the getServerSideProps. You can learn more about it in the Next.js documentation : Server-side rendering. In this demo, we will be using the "Pages Router"

You can implement Server-Side Rendering by using the getServerSideProps function. Directly export an async getServerSideProps function from the page file to which you wish to add it. This function is called every time the page is requested, and its output provides the props used to generate the page.

Now, create a new Next.js project by running the command below.

npx create-next-app@latest ssr-application

Using the command above, we created a new Next.js application named ssr-application.

After successful installation, change into your new project using the command below:

cd ssr-application

Next, navigate to your src/pages/index.tsx file and replace the code inside it with the following code:

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import React from "react";

// Simulate fetching data from the server
async function fetchServerData() {
  return "Hi, my name is Mercy Tanga, I'm a software developer and a technical writer. This data is fetched on the server side.";
}

const About = ({ serverData }) => (
  <div>
    <h1>About Page</h1>
    <p>{serverData}</p>
  </div>
);

export default About;

// Fetch server-side data
export async function getServerSideProps() {
  const serverData = await fetchServerData();
  return {
    props: {
      serverData,
    },
  };
}

The code above creates a simple About page demonstrating how server-side data can be retrieved and displayed within a React component in a Next.js environment. The getServerSideProps function fetches data on the server side, and the About component receives this data as a prop and renders it. This ensures the page content is always up-to-date with each request, providing users a dynamic and real-time experience.

Next, enter the command below in your terminal to run your app:

npm run dev

Here is the final result:

Static Site Generation (SSG)

A Static Site Generator (SSG) is a tool that creates a complete static HTML website from raw data and a collection of templates. It automates writing individual HTML pages and prepares them to be sent to users beforehand. Because these HTML pages are pre-built, they will load rapidly in users' browsers.

SSG is like printing out your website pages ahead of time so that visitors can access them immediately, resulting in a faster and more efficient browsing experience. It's ideal for blogs or documentation sites with relatively static content.

How Does SSG Work?

Working with SSG is quite simple. At build time, before content reaches the content delivery network (CDN), SSG will read through the files, render the content to HTML using templates, and serve it to the CDN. If the result matches the resource file, it remains CDN-ready whenever end users make a request.

Pros of SSG

• Performance: SSG-generated pages are pre-built and delivered as static HTML files through a CDN or static hosting, ensuring rapid load times. For example, a blog site using SSG can offer readers instant access to articles, enhancing user experience with quick and seamless navigation.
• Scalability: Static websites scale efficiently during high-traffic periods because they require minimal server resources. For instance, an e-commerce site with static product catalog pages can seamlessly handle thousands of users simultaneously during peak sales events, ensuring a smooth shopping experience.
• SEO-Friendly: Static HTML content can improve SEO performance because it is easy for search engines to index.
• Cost-Efficiency: Saving money on hosting static files is usually more affordable than maintaining dynamic server-side resources.

Cons of SSG

• Absence of Server-Side Logic: SSG does not handle user-specific content or server-side logic by default. This means it can't easily create personalized pages for each user, like showing their account details or preferences. SSG works best for static content that doesn't change per user. If you need dynamic content, like customized user dashboards, you'll need to explore other methods.
• Few or no pre-built templates: Since many static site generators lack templates, you will first need to invest significant effort in creating them from scratch.
• No user-friendly interface: Using a static site generator to publish content is more difficult for people who are not developers.

When is The Best Time to Use SSG?

When you want a high-performing, scalable website and your content is primarily constant over time, Next.js's SSG is the best option. Because SSG pre-builds pages into static HTML during the build process, there is less server load and a faster user experience thanks to the created pages. Because of this, SSG is perfect for websites with infrequent content updates, such as blogs, marketing sites, portfolios, or documentation pages.

How to implement SSG in Next.js

If we are using the "Page Router" in Next.js, contrary to the "App router" for routing, we have to use the getStaticProps. You can learn more about it in the Next.js documentation : Static Site Generation. In this demo, we will be using the "Pages Router"

To implement SSG in your Next.js application, directly export a function called getStaticProps from the page you want to generate. When Next.js detects this function, it can pre-render the page at build time using SSG during the next build process.

Now, create a new Next.js project like so:

npx create-next-app@latest ssg-application

Next, change into your project directory with the command below:

cd ssg-application

Next, navigate to your src/pages/index.tsx directory and replace the following code:

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import React from "react";

// Function to fetch posts from the API
async function fetchPosts() {
  const response = await fetch("https://dev.to/api/articles");

  // Check if the response is successful
  if (!response.ok) {
    throw new Error("Failed to fetch posts");
  }

  // Parse the JSON data from the response
  const data = await response.json();
  return data;
}

// Main Posts component to display the fetched posts
const Posts = ({ posts }) => (
  <div>
    <h1>Blog Posts</h1>
    <ul>
      {posts.map((post) => (
        <li key={post.id}>{post.title}</li> // Display each post title
      ))}
    </ul>
  </div>
);

export default Posts;

// Fetch the posts at build time
export async function getStaticProps() {
  const posts = await fetchPosts();
  return {
    props: {
      posts,
    },
  };
}

The code above creates a simple Next.js page that utilizes SSG to fetch and show a list of blog articles from the dev.to API. The data is fetched at build time, and the getStaticProps function pre-generates the HTML for this page, making it static, fast, and efficient.

Now launch your program with the following command:

npm run dev

Here is the final result of our simple blog page:

Use case of SSR and SSG

SSR and SSG serve different interests and meet a wide range of your needs. Understanding each strategy's other qualities and applications is essential in selecting the appropriate one for your project.

Let's compare some features based on the following criteria:

How to Choose Between SSR and SSG

Still unsure which strategy to use to begin your front-end journey? Use the decision diagram below to decide which method to pursue.

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Other SSR and SSG Frameworks You Should Know

Various frameworks for implementing SSG and SSR provide a broad collection of tools for implementing SSG and SSR, catering to different technology stacks and project needs. Whether you're creating a fast, scalable static site or a dynamic application with server-side logic, these frameworks provide a variety of alternatives:

• Gatsby.js: A popular React-based SSG renowned for its suitability for static webpages due to its extensive capabilities and optimal performance. You might want to check out How to Build a Static Blog with Gatsby and Strapi.
• Nuxt.js: A popular Vue.js framework that supports SSG and SSR, providing many features for building modern online apps. Here is an interesting blog post: Build a blog with Nuxt (Vue.js), Strapi and Apollo.
• Hugo: A fast and versatile SSG designed with the Go programming language, perfect for blogs, documentation, and other static content-rich websites. You might want to check this guide on using Hugo: A Guide to Using Hugo.
• Angular Universal: An Angular extension that pre-renders Angular applications on the server, which improves SEO and speeds up initial load times. Check out Using Strapi with Angular Universal Apps.
• Jekyll: A Ruby-based SSG framework popular among GitHub Pages users. Jekyll is bare, making it ideal for simple blogs and static websites. Learn more on Building a static blog using Jekyll and Strapi.
• Eleventy: An SSG framework designed for flexibility and simplicity. Eleventy supports different templating languages, giving you greater flexibility in creating your static site. Learn more about Eleventy: Building a Blog with 11ty and Strapi
• Remix: A React-based SSR framework for building fast, dynamic web applications. Remix emphasizes fluid navigation and data fetching, making it an excellent solution for apps that require complicated routing and server-side data exchanges. Compare Remix and other frameworks in this blog post: Next.js vs Astro vs Remix: Choosing the Right Front-end Framework

Factors to Consider When Choosing SSR and SSG

The choice between SSR and SSG in Next.js depends on the factors below. Before deciding between SSR and SSG, it is essential to understand your project's specific requirements and limitations. We'll take into consideration the following factors to figure out the best approach:

1. Content Requirements

When tackling Content Requirements in a web development setting, you should consider how the nature and frequency of content updates affect the decision between SSR and SSG.

Assuming you're creating an e-commerce website with the following page, product listings, descriptions, customer reviews, and promotions. These content requirements are dynamic and significantly affected by product upgrades, sales, and customer interactions. Here, the decision between SSR and SSG is based on how these content restrictions influence you.

Understanding your content needs is essential for determining the appropriate rendering method for your project.

2. Performance Needs

Performance needs revolve around speed and scalability, with less emphasis on real-time updates. SSG often provides better speed since static pages can be cached and served quickly. It's ideal for high-traffic websites where speed and scalability are vital. On the other hand, SSR is slower because it requires server-side calculation for each request, which may affect response time.

Note: SSR and SSG are both effective ways to improve the performance of your Next.js application.

As seen in the image above, SSR delivers and ensures that dynamic content on your website is up to date, whereas SSG creates fast-loading, pre-generated pages.

3. Development and Maintenance Complexity

SSG is an ideal choice because it simplifies development and maintenance. However, if you desire real-time data, dynamic changes, or tailored content, SSR offers flexibility at a more significant development and maintenance cost.

Startup companies with small teams often choose SSG for its simplicity and ease of maintenance. It allows you to focus on building features without worrying about managing server infrastructure.

4. SEO Considerations

SSG and SSR are both excellent for SEO, even though each has advantages and disadvantages. They construct their HTML outputs on the server at either build or request time.

Also, both rendering techniques produce pages swiftly, which improves SEO ranks. SSG will be more helpful if you have a vast site and can use it, as it renders faster than the other option.

A marketing site like Tesla microsite benefits from SSG's fast load times and excellent SEO performance for static content.

5. Team Expertise and Resources

Given the necessity for frequent updates and personalized content, your team should use SSR, which can manage databases, APIs, and other server-related duties.

However, if your team works on a simple portfolio site for a freelance designer, the content is mostly static, with occasional modifications to highlight new projects or testimonials. Your team should choose SSG.

In summary, if your team possesses the knowledge and resources to handle server-side activities, SSR might be an excellent alternative, particularly for dynamic applications. Otherwise, SSG might be more suited for basic sites.

Conclusion

This article compares Static Site Generation and Server-Side Rendering in Next.js, covering their use cases, pros, cons, and implementation strategies. While each has its strengths, choosing between them is like comparing apples and pears—they each serve unique purposes and are suited to different needs.

Understanding your project's goals and limitations is crucial for making an informed decision. Evaluate the factors discussed to determine whether SSR or SSG best fits your Next.js application.

Ready to dive in? Try implementing SSR or SSG in your projects to see how these rendering strategies can enhance your site's performance and maintainability. Experiment, learn, and optimize to deliver the best possible user experience. Happy coding!