Understanding Server-Side Rendering vs. Static-Site Generation in Next.js

In modern web development, rendering strategies play a crucial role in determining website performance, scalability, and user experience. Next.js is a popular framework that gives developers flexibility by offering both Server-Side Rendering (SSR) and Static-Site Generation (SSG). Understanding these two strategies helps developers choose the right approach for their projects. In this article, we’ll explore SSR and SSG in detail, their benefits and drawbacks, technical implementations, SEO considerations, and when to use each.

What is Server-Side Rendering (SSR)?

Server-Side Rendering generates HTML on each request. When a user visits a page, the server fetches data, processes it, and returns a fully rendered HTML page.

In Next.js, SSR is implemented using the getServerSideProps function. Example:

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

Benefits of SSR:

• Dynamic Content: Ideal for pages requiring real-time data.

• SEO-Friendly: Fully rendered HTML helps search engines understand and rank the page.

• Personalization: Enables delivering user-specific content.

Drawbacks of SSR:

• Slower Response Time: Every request triggers data fetching and rendering.

• Increased Server Load: High traffic can strain the server.

Visual Example:

User Request ➡ Server Fetches Data & Renders ➡ HTML Sent to User

Common Use Cases:

• E-commerce product pages with real-time pricing.

• Personalized user dashboards.

• News feeds with live updates.

---

What is Static-Site Generation (SSG)?

Static Generation pre-renders pages at build time. The result is static HTML files that are served immediately when requested.

In Next.js, SSG is implemented using getStaticProps. Example:

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

Benefits of SSG:

• Lightning-Fast Performance: Pages are pre-built and served from a CDN.

• Reduced Server Load: No rendering on each request.

• Highly Scalable: Can handle sudden traffic spikes easily.

Drawbacks of SSG:

• Outdated Data: Pages can become stale without regular re-deployment or revalidation.

• Long Build Times: For large projects, build times can increase.

Visual Example:

Build Time ➡ Pages Pre-rendered ➡ Served Instantly to Users

Common Use Cases:

• Marketing pages.

• Blogs and documentation.

• Portfolios and static websites.

---

SEO Considerations: SSR vs. SSG

Both SSR and SSG contribute positively to SEO, but in different ways:

• SSR: Excellent for dynamic content and pages that require real-time updates. Ensures search engines always crawl the most recent content.

• SSG: Provides faster page load times, a key factor in SEO ranking and user experience. Pages served from CDN have minimal latency.

• User Experience: Fast-loading static pages (SSG) often lead to lower bounce rates, while SSR ensures fresh, relevant content.

---

How to Choose Between SSR and SSG

Incremental Static Regeneration (ISR)

Next.js offers ISR as a hybrid solution. Pages are statically generated but can be updated after deployment based on a specified revalidation time.

export async function getStaticProps() {
  return {
    props: {},
    revalidate: 10, // Regenerate page every 10 seconds
  };
}

---

Conclusion

Choosing between Server-Side Rendering and Static Generation is essential for building performant, scalable, and user-friendly applications. SSR is best for dynamic, real-time content and personalization, while SSG provides unmatched speed and scalability for static or rarely changing content.

To summarize:

• Use SSR when content needs to be up-to-date per request.

• Use SSG when you can pre-build pages and want to maximize speed.

• Consider ISR for projects that need regular content refreshes without redeployment.

Next.js makes it easy to mix and match these approaches across different pages. If you’re looking to dive deeper, start experimenting with both SSR and SSG in small projects. Understanding these concepts not only improves your technical skills but also helps you deliver better user experiences and SEO-friendly websites.