Imagine you’re running a bookstore and you get a huge order: 10,000 copies of the same bestseller. You wouldn’t hand-write each book on the spot—you’d print them all in advance and ship instantly when orders come in. That’s the core idea behind Static Site Generation (SSG) in Next.js: you “print” HTML pages at build time, so when users request a page, the server can serve a ready-made file without running code on each request.

What Is SSG?

Static Site Generation means generating fully rendered HTML pages during your build process rather than on every user request. Instead of fetching data and rendering templates on the fly, Next.js runs your page components ahead of time, substitutes data, and outputs static .html files. When a visitor lands on your page, they get a pre-built asset—no server-side rendering needed at runtime.

Why Use SSG?

1. Performance: Serving static files is as fast as it gets—your pages come with minimal latency since they’re just files on a CDN.
2. Scalability: Static assets scale effortlessly—you can handle massive traffic spikes without spinning up extra servers or processes.
3. Security: With no server logic running per request, your attack surface shrinks. There’s no database connection to exploit at runtime.
4. Cost Efficiency: Hosting static files on a CDN or object storage is often cheaper than running dedicated servers or serverless functions.

SSG shines for content-driven sites—blogs, documentation, marketing pages—where data changes infrequently or can be rebuilt on a schedule.

How Next.js Implements SSG

Next.js provides getStaticProps and getStaticPaths to power SSG:

• getStaticProps fetches data at build time and passes it as props to your page component.
• getStaticPaths tells Next.js which dynamic routes to generate ahead of time.

Example: A Blog with Pre-Built Pages

// pages/posts/[slug].js

export async function getStaticPaths() {
const posts = await fetch('https://api.example.com/posts').then(res => res.json());
return {
paths: posts.map(post => ({ params: { slug: post.slug } })),
fallback: false
};
}

export async function getStaticProps({ params }) {
const post = await fetch(`https://api.example.com/posts/${params.slug}`).then(res => res.json());
return { props: { post } };
}

export default function PostPage({ post }) {
return (
<>
<h1>{post.title}</h1>
<article dangerouslySetInnerHTML={{ __html: post.content }} />
</>
);
}

• At build time, Next.js calls getStaticPaths to list all blog slugs.
• For each slug, it runs getStaticProps and generates an HTML file at posts/slug.html.
• Visitors get static pages served instantly from a CDN.

Advanced: Incremental Static Regeneration (ISR)

What if your content updates regularly—say, you add new blog posts daily? Rebuilding your entire site every time can be slow. Next.js’s ISR lets you specify a revalidate interval in seconds:

export async function getStaticProps() {
const posts = await fetch('https://api.example.com/posts').then(res => res.json());
return {
props: { posts },
revalidate: 60 // rebuild this page in the background at most once every 60 seconds
};
}

With ISR, Next.js serves the existing static page while rebuilding a fresh version in the background once the revalidate window passes. This gives you the best of both worlds: static-site speed with near-real-time updates.

Integrating Headless CMS and APIs

SSG pairs perfectly with headless CMS platforms (Contentful, Sanity, Strapi) or any REST/GraphQL API. You configure getStaticProps to pull content from your CMS, and every build—manual, CI-triggered, or webhook-initiated—recreates your site with the latest data.

Use Cases for Next.js SSG

• Blogs & Documentation: Pre-render chapters, tutorials, and guides for ultra-fast reading.
• Marketing & Landing Pages: Serve heroic banners, feature sections, and calls-to-action instantly.
• E-commerce Catalogs: Pre-generate product listing pages; combine with client-side fetching for inventory.
• Portfolios & Galleries: Showcase your work with minimal latency and maximum SEO benefit.

Wrapping Up

Next.js’s Static Site Generation empowers you to build sites that load in the blink of an eye, scale effortlessly, and stay secure—all with a familiar React framework and a few simple functions. Whether you’re starting a personal blog or architecting a global documentation portal, SSG lets you pre-build your content and serve it from a CDN, ensuring your users enjoy fast, reliable experiences.

Give SSG a try for your next project: define your data-fetching logic in getStaticProps, map out dynamic routes in getStaticPaths, and let Next.js handle the rest. You’ll end up with a site that feels instant—because it really is.