Next.js SSG vs SSR: Choosing the Right Approach

As a software engineer who ships production apps with Next.js, I’ve had the “SSG vs SSR” conversation more times than I can count. It usually starts with, “Which one is faster?” or “Which one is better for SEO?”—but the real answer depends on your use case, data patterns, and user expectations.

I’m Phong Lee, and in this post I’ll walk through how I think about choosing between Static Site Generation (SSG) and Server-Side Rendering (SSR) in real-world projects—not just in theory.

Quick refresher: SSG vs SSR in Next.js

• SSG (Static Site Generation):
  Pages are generated at build time and served as static HTML, often with cached assets at a CDN edge. Great for performance and scalability when content does not change on every request.

• SSR (Server-Side Rendering):
  Pages are rendered on each request (or with caching strategies) using getServerSideProps or the new Next.js App Router server components pattern. Great when content must be fresh and user-specific.

Both can deliver excellent SEO and performance when used correctly. The question is: which matches your content and business needs?

When I reach for SSG

I gravitate toward SSG when:

• The content is mostly static or changes on a predictable schedule.
• SEO is critical (e.g., blogs, marketing pages, product catalogs).
• I want to offload load to CDNs and keep runtime infrastructure simple.

Examples from my own experience:

• Blog articles like the one you’re reading now.
• “About,” “Pricing,” and “Features” pages.
• Documentation and resource centers.

The benefits I see in practice:

• Blazing fast performance: static HTML served from the edge.
• Excellent cacheability: fewer moving parts, less to break under load.
• Lower hosting costs: minimal server-side compute per request.

But what about dynamic data?

Even with SSG, you can still show dynamic pieces by:

• Using client-side fetching (e.g., useEffect + fetch or React Query) for non-critical live data.
• Leveraging Incremental Static Regeneration (ISR) to rebuild pages in the background when content changes.

For example, I might:

• Pre-render a product page statically.
• Use ISR to refresh it every few minutes or when new data is published.
• Hydrate dynamic sections (like “currently in stock”) on the client.

This hybrid approach gives you the best of both worlds: fast initial loads and reasonably fresh data.

When I choose SSR

On the other hand, I reach for SSR when:

• The page must be tailored to the specific user or request.
• The data changes on almost every request.
• SEO still matters, but content can’t be pre-generated effectively.

Examples:

• Personalized dashboards.
• User-specific recommendations.
• Pages that depend on auth state and sensitive data on first load.

In these cases, SSR lets me:

• Fetch user-specific data securely on the server.
• Render HTML that already contains tailored content.
• Avoid flashing “loading” states for critical above-the-fold information.

The trade-off is:

• Higher server load per request.
• Potentially more latency compared to edge-cached static pages.
• More complexity in scaling and caching.

SEO: SSG vs SSR in real life

People often ask, “Which is better for SEO, SSG or SSR?” In practice:

• Both approaches produce fully rendered HTML that search engines can crawl.
• What really matters is content quality, performance, and stability.

From an SEO perspective, I focus on:

• Fast Largest Contentful Paint (LCP) and good Core Web Vitals.
• Consistent, crawlable URLs and sitemaps.
• Proper use of meta tags, Open Graph, and structured data.

SSG makes fast performance easier by default. SSR can match it with good caching and infrastructure, but it takes more engineering effort.

My decision framework: questions I always ask

When deciding between SSG and SSR for a new Next.js page, I run through this checklist:

1. How often does the data change?

   • Rarely → SSG (possibly with ISR).
   • Frequently or per-request → SSR or client-side fetching.

2. Is the page personalized on first load?

   • No → SSG is a strong candidate.
   • Yes → SSR or client-side auth logic.

3. How critical is first-page SEO?

   • Very high → prioritize SSG or SSR with HTML including all key content.
   • Lower → CSR or hybrid approaches may be fine.

4. What are my scaling and cost constraints?

   • Need to handle huge spikes cheaply → SSG + CDN is ideal.
   • Have robust backend infrastructure → SSR can be fine.

5. Do I control the content lifecycle?

   • If content flows through a CMS or scheduled updates → SSG + ISR works great.
   • If content is highly real-time or transactional → SSR or API-driven CSR.

Real-world hybrid architectures

In real projects, I almost never choose only SSG or only SSR. Instead, I combine them:

• Marketing and blog pages: SSG + ISR for speed and SEO.
• Authenticated areas: SSR or server components for secure, personalized data.
• Low-priority or real-time widgets: client-side fetching layered on static shells.

For example, a SaaS product site might use:

• SSG for the landing page, pricing, and feature pages.
• SSG + ISR for public case studies and blog posts.
• SSR for logged-in dashboards.
• API routes for background jobs and integrations.

This hybrid strategy maps rendering methods to business needs, not just technical preferences.

How I think about SSG vs SSR today

As Phong Lee, my rule of thumb is:

• Default to SSG for anything public, mostly-static, and SEO-sensitive.
• Add ISR when content changes but doesn’t need to be real-time.
• Use SSR when you truly need request-specific, secure, or highly dynamic content on first paint.
• Layer client-side fetching for non-critical or frequently refreshing pieces.

Next.js gives us a flexible toolbox. The art is choosing the right tool for each page based on:

• Data patterns
• Personalization needs
• Performance goals
• Operational complexity

If you treat SSG and SSR as strategic choices instead of dogmatic camps, you’ll end up with faster, more reliable, and more maintainable applications that serve both your users and your business well.