Static Site Generation vs Server-Side Rendering: Choosing Your Rendering Strategy

Choosing between Static Site Generation (SSG) and Server-Side Rendering (SSR) is one of the most consequential architectural decisions for a modern web application. Frameworks like Next.js, Nuxt, and Gatsby support both approaches, but many teams default to one or the other without fully considering the trade-offs. This guide breaks down when each strategy excels and how modern hybrid approaches can give you the best of both worlds.

Static Site Generation: Pre-Built Performance

SSG generates HTML pages at build time. Every page is pre-rendered into a static HTML file, which is then served directly from a CDN without any server-side processing. The result is instant page loads — the CDN can serve millions of requests from edge caches with essentially zero compute cost.

When SSG excels:

• Content-driven sites (blogs, documentation, marketing pages)
• Sites where content changes infrequently
• High-traffic pages that need maximum performance with minimum infrastructure cost
• Sites that must work without JavaScript (static HTML always works)

When SSG struggles:

• Content that updates multiple times per minute (live scores, real-time dashboards)
• Personalized pages that differ per user (logged-in states, recommendations)
• Sites with millions of pages — build times can become prohibitive

Server-Side Rendering: Dynamic and Fresh

SSR generates HTML on-demand for each request. When a user visits a page, the server fetches the data, renders the React or Vue component to HTML, and sends the complete page to the client. SSR ensures content is always fresh and can be personalized per request.

When SSR excels:

• E-commerce product pages with real-time inventory and pricing
• Social media feeds and personalized dashboards
• Sites requiring authentication-gated content
• Pages where SEO matters but content changes too frequently for SSG

When SSR struggles:

• High-traffic spikes — every request hits the server, requiring auto-scaling
• Global audiences — latency increases with geographic distance from the server
• Higher infrastructure costs compared to static CDN delivery

Incremental Static Regeneration: The Hybrid Sweet Spot

Incremental Static Regeneration (ISR), introduced by Next.js, combines the performance of static generation with the freshness of SSR. With ISR, pages are statically generated at build time but can be regenerated on-demand or on a schedule without rebuilding the entire site:

export async function getStaticProps({ params }) {
  const data = await fetchProduct(params.slug);
  return {
    props: { product: data },
    revalidate: 300, // Revalidate at most every 5 minutes
  };
}

On-demand ISR (Next.js 12.1+) takes this further by allowing you to trigger revalidation via a webhook when content changes:

// API route for revalidation
export default async function handler(req, res) {
  if (req.query.secret !== process.env.REVALIDATION_TOKEN) {
    return res.status(401).json({ message: 'Invalid token' });
  }
  await res.revalidate(req.query.path);
  return res.json({ revalidated: true });
}

This means your CMS can trigger page revalidation only when content actually changes, rather than on an arbitrary timer.

Edge Rendering: Server-Side at CDN Speed

Edge rendering pushes SSR to CDN edge nodes. Instead of rendering on a central server in one region, your pages are rendered on servers in 50+ locations worldwide. Frameworks like Next.js (Edge Runtime), Remix, and Qwik support this model.

Edge rendering is particularly powerful for:

• International e-commerce — product pages render in the user's nearest edge server with localized pricing and inventory
• A/B testing — serve different variants from the edge without cache busting
• Personalization — render personalized hero banners and recommendations at the edge

// next.config.js
export const config = {
  runtime: 'edge',
};

The trade-off: the Edge Runtime has limitations — no Node.js file system access, limited API compatibility, and a maximum execution time of 30 seconds (or less on some platforms).

Choosing Your Strategy Per Page

The most effective approach is not to choose one globally, but to use a per-page strategy. In Next.js, you can combine all three approaches in a single project:

• Marketing pages → SSG (build-time generated, served from CDN)
• Product pages → ISR (statically generated, revalidated per CMS webhook)
• User dashboard → SSR (server-rendered per request with auth)
• Cart page → Edge SSR (rendered at edge with regional pricing)

// Marketing page - SSG
export getStaticProps = ... (with revalidate: false or a long interval)

// Product page - ISR
export getStaticProps = ... (with revalidate: 60)

// Dashboard - SSR
export getServerSideProps = ... (always server-render)

Infrastructure and Cost Implications

SSG with a CDN is the cheapest option — Vercel's free tier handles unlimited static pages. Edge SSR costs slightly more but avoids the need for regional server deployment. Traditional SSR requires autoscaling server capacity and can be 5-10x more expensive than static delivery for high-traffic pages.

Making the Decision

Start by analyzing your content update frequency. Pages updated less than once per hour are candidates for ISR or SSG. Pages that must reflect real-time state are SSR candidates. Pages that need personalization with content freshness are best served by edge rendering.

Not sure which rendering strategy fits your project? SoniNow's web development team helps teams architect performant Next.js applications using the right mix of SSG, SSR, ISR, and edge rendering. Contact us for a consultation.