Understanding Static Site Generation (SSG) in Next.js and When to Use It

Static Site Generation (SSG) is a powerful feature provided by Next.js that pre-renders pages at build time. This means that HTML pages are generated in advance during the build process, which results in fast-loading, SEO-friendly websites. In this article, we'll delve into what SSG is, how it works in Next.js, and scenarios where it should be used.

What is Static Site Generation (SSG)?

Static Site Generation (SSG) is a method of pre-rendering web pages into static HTML files at build time. Unlike Server-Side Rendering (SSR), where pages are rendered on the server at request time, SSG generates the complete HTML content for each page ahead of time. This approach leverages the power of build tools to create a fully static version of a website that can be served from a Content Delivery Network (CDN), resulting in faster load times and improved performance.

In the context of Next.js, SSG is implemented using the getStaticProps and getStaticPaths functions. getStaticProps fetches the necessary data at build time to generate static pages, while getStaticPaths is used to specify dynamic routes that should be statically generated.

How Does SSG Work in Next.js?

In Next.js, Static Site Generation (SSG) works by pre-rendering pages at build time. Using the getStaticProps function, Next.js fetches data needed to render the page during the build process. The result is static HTML files that are generated and served quickly to users. For dynamic routes, getStaticPaths defines which paths to pre-render. This approach ensures fast load times, improved performance, and better SEO, as pages are fully rendered before being served to users.

Benefits of (SSG)

Performance

• Fast Load Times: Pages are pre-rendered into static HTML at build time, allowing them to load quickly from a CDN.
• Reduced Server Load: Since static files are served, there’s minimal server processing required, reducing server load and costs.

Scalability

• Efficient Handling of Traffic: Static files can be easily distributed across CDNs, enabling efficient handling of high traffic volumes without performance degradation.
• Global Distribution: Serving static content from multiple geographical locations ensures faster access for users worldwide.

SEO Optimization

• Fully Rendered Pages: Search engines can index fully rendered HTML pages, improving SEO.
• Improved Search Rankings: Fast load times and optimized content structure can lead to better search engine rankings.

Security

• Reduced Attack Surface: Static sites do not rely on server-side processing, thus reducing potential vulnerabilities such as database attacks.
• No Server-Side Dependencies: Eliminates risks associated with server-side code execution and dependencies.

Developer Experience

• Simplified Hosting: Static files can be hosted on various platforms, including GitHub Pages, Vercel, and Netlify, simplifying deployment.
• Predictable Builds: Pre-determined build process ensures consistent and predictable page rendering without runtime surprises.

Example of SSG in Next.js

A blog site (like ours as an example) is an excellent example of leveraging Static Site Generation (SSG) in Next.js. Blogs often have content that changes infrequently and benefit greatly from fast load times and excellent SEO.

Example: Building a Blog with SSG

Directory Structure:

  /posts
    [id].js
  index.js
/lib
  posts.js

Step-by-Step Implementation

Fetch Blog Data

Create a file posts.js in the lib directory to fetch or read blog data.

// lib/posts.js
import fs from "fs";
import path from "path";
import matter from "gray-matter";

const postsDirectory = path.join(process.cwd(), "posts");

export function getAllPostIds() {
  const fileNames = fs.readdirSync(postsDirectory);
  return fileNames.map((fileName) => ({
    params: {
      id: fileName.replace(/\.md$/, ""),
    },
  }));
}

export function getPostData(id) {
  const fullPath = path.join(postsDirectory, `${id}.md`);
  const fileContents = fs.readFileSync(fullPath, "utf8");
  const { data, content } = matter(fileContents);

  return {
    id,
    ...data,
    content,
  };
}

Define Dynamic Routes

Create a dynamic page pages/posts/[id].js to display individual blog posts. These dynamic routes help to make routing in a blog site much faster than usual.

// pages/posts/[id].js
import { getAllPostIds, getPostData } from "../../lib/posts";

export async function getStaticProps({ params }) {
  const postData = getPostData(params.id);
  return {
    props: {
      postData,
    },
  };
}

export async function getStaticPaths() {
  const paths = getAllPostIds();
  return {
    paths,
    fallback: false,
  };
}

const Post = ({ postData }) => (
  <div>
    <h1>{postData.title}</h1>
    <p>{postData.date}</p>
    <div dangerouslySetInnerHTML={{ __html: postData.content }} />
  </div>
);

export default Post;

Create Home Page

List all blog posts on the home page pages/index.js.

// pages/index.js
import Link from "next/link";
import { getAllPostIds, getPostData } from "../lib/posts";

export async function getStaticProps() {
  const allPostsData = getAllPostIds().map(({ params }) =>
    getPostData(params.id),
  );
  return {
    props: {
      allPostsData,
    },
  };
}

const Home = ({ allPostsData }) => (
  <div>
    <h1>My Blog</h1>
    <ul>
      {allPostsData.map(({ id, title }) => (
        <li key={id}>
          <Link href={`/posts/${id}`}>
            <a>{title}</a>
          </Link>
        </li>
      ))}
    </ul>
  </div>
);

export default Home;

Markdown Files

Store blog content in markdown files in the posts directory.

  first-post.md
  second-post.md

Example markdown file (first-post.md):

---
title: "First Post"
date: "2024-06-30"
---

This is the content of the first post.

This example illustrates how to use Static Site Generation (SSG) in Next.js to build a blog. By pre-rendering pages at build time, you ensure fast load times, improved SEO, and a seamless user experience. This setup is scalable, secure, and easy to maintain, making it an ideal solution for many static content websites.

When Should Static Site Generation (SSG) Be Used?

SSG in Next.js should be used when you have content that does not change frequently, need to optimize for SEO, require high performance and scalability, or have pages that can benefit from being pre-rendered due to expensive computations. By using SSG, you can deliver faster, more reliable experiences to your users while reducing server load and enhancing SEO.

Content-Heavy Websites

SSG is ideal for content-heavy websites such as blogs, documentation sites, and marketing pages. These sites often have content that doesn't change frequently and benefits from fast load times and excellent SEO.

Example:

• Blog or News Sites: Articles and posts are generated at build time and served as static pages, ensuring quick load times for readers.
• Documentation: Product or API documentation sites where content updates are relatively infrequent.

export async function getStaticProps() {
  const posts = await fetchPosts();
  return { props: { posts } };
}

const Blog = ({ posts }) => (
  <div>
    {posts.map((post) => (
      <div key={post.id}>
        <h2>{post.title}</h2>
        <p>{post.content}</p>
      </div>
    ))}
  </div>
);

export default Blog;

SEO-Optimized Pages

SSG provides SEO benefits by delivering fully rendered HTML to search engines, which can be crucial for marketing pages and e-commerce sites.

Example:

• Landing Pages: Optimized for specific keywords to improve search engine ranking.
• Product Pages: Pre-rendered product information to ensure quick access and better indexing by search engines.

export async function getStaticProps() {
  const product = await fetchProduct();
  return { props: { product } };
}

const ProductPage = ({ product }) => (
  <div>
    <h1>{product.name}</h1>
    <p>{product.description}</p>
  </div>
);

export default ProductPage;

Pages with Minimal Dynamic Content

Use SSG for pages that do not require frequent updates or real-time data. Static content that rarely changes is perfect for SSG.

Example:

• About Us Page: Company information that doesn’t change often.
• Contact Page: Static information like contact details, office addresses, etc.

const About = () => (
  <div>
    <h1>About Us</h1>
    <p>We are a company dedicated to providing excellent services.</p>
  </div>
);

export default About;

Scalable and High-Performance Sites

SSG is beneficial for sites that need to handle a large volume of traffic efficiently. Serving static files from a CDN can significantly reduce server load and improve site performance.

Example:

• Portfolio Websites: Personal or professional portfolios showcasing projects or artworks.
• Event Sites: Information about events, conferences, or meetups that do not change often.

export async function getStaticProps() {
  const portfolioItems = await fetchPortfolioItems();
  return { props: { portfolioItems } };
}

const Portfolio = ({ portfolioItems }) => (
  <div>
    {portfolioItems.map((item) => (
      <div key={item.id}>
        <h2>{item.title}</h2>
        <img src={item.imageUrl} alt={item.title} />
      </div>
    ))}
  </div>
);

export default Portfolio;

Pages with Expensive Computation or Data Fetching

If your page requires complex computations or data fetching that is not feasible to perform on every request, SSG can pre-compute this data at build time, reducing the load on your servers.

Example:

• Data-Intensive Reports: Pre-computed analytics or reports that are updated periodically rather than in real-time.

export async function getStaticProps() {
  const reportData = await generateReportData();
  return { props: { reportData } };
}

const ReportPage = ({ reportData }) => (
  <div>
    <h1>Analytics Report</h1>
    <pre>{JSON.stringify(reportData, null, 2)}</pre>
  </div>
);

export default ReportPage;

Nextjs FAQ

export async function getStaticProps() {
  const res = await fetch("https://api.example.com/data");
  const data = await res.json();
  return { props: { data } };
}

const Page = ({ data }) => (
  <div>
    <h1>{data.title}</h1>
    <p>{data.content}</p>
  </div>
);

export default Page;

export async function getStaticProps() {
  const res = await fetch("https://api.example.com/data", {
    headers: {
      Authorization: `Bearer ${process.env.API_KEY}`,
    },
  });
  const data = await res.json();
  return { props: { data } };
}

Conclusion

Static Site Generation (SSG) is a powerful feature offered by Next.js that generates pre-rendered HTML pages at build time. This approach improves performance, enhances SEO, and reduces server load, making it ideal for websites with static or infrequently changing content. By leveraging SSG in Next.js, developers can create fast, scalable, and SEO-friendly web applications that provide a seamless user experience.

Make sure you read this article on the same topic on my medium https://medium.com/@farihatulmaria/the-difference-between-client-side-rendering-csr-server-side-rendering-ssr-and-static-site-64daade451b5