Performance advantages of static site generation (SSG)

Performance Advantages of Static Site Generation (SSG)

Static Site Generation (SSG) is a technology that pre-generates all HTML pages at build time. Compared to traditional server-side rendering (SSR) or client-side rendering (CSR), SSG offers significant performance advantages, particularly in page load speed, server resource consumption, and caching efficiency.

Performance Gains from Pre-Rendering

The core advantage of SSG lies in pre-rendering. All pages are generated during the build phase, and static HTML files are directly returned to users upon request, eliminating the need for real-time rendering. This approach reduces server-side computational pressure while significantly improving page load speed.

Take Next.js as an example in SSG mode:

// pages/posts/[id].js
export async function getStaticProps({ params }) {
  const postData = await getPostData(params.id);
  return {
    props: {
      postData,
    },
  };
}

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

In this mode, all article pages are generated at build time, and users receive pre-rendered HTML directly without waiting for server processing.

Reduced Server Load

Dynamically rendered websites require substantial server resources to handle each request under high traffic. SSG-generated static files can be distributed via CDN, significantly reducing server load.

Comparison of two scenarios:

1. Dynamic rendering: 10,000 requests = 10,000 database queries + 10,000 template renderings
2. SSG: 10,000 requests = 0 database queries + 0 template renderings (only file transfers)

Maximized Caching Efficiency

Static files are inherently cache-friendly. CDNs can easily cache SSG-generated pages, enabling edge node delivery and further reducing latency.

Configuration example (.htaccess):

<IfModule mod_expires.c>
  ExpiresActive On
  ExpiresByType text/html "access plus 1 year"
  ExpiresByType text/css "access plus 1 year"
  ExpiresByType application/javascript "access plus 1 year"
</IfModule>

Optimized First-Paint Load Time

SSG eliminates uncertainty in Time To First Byte (TTFB) because:

• No waiting for API responses
• No server-side rendering
• No client-side hydration (in pure static scenarios)

Measured data comparison (same content):

• SSR average TTFB: 300-500ms
• SSG average TTFB: 20-50ms

Better Core Web Vitals

SSG typically achieves higher Core Web Vitals scores:

• LCP (Largest Contentful Paint): Static resources can be prioritized
• FID (First Input Delay): No JS blocking
• CLS (Cumulative Layout Shift): Content is predetermined

Static Resource Optimization

SSG works seamlessly with modern frontend toolchains for resource optimization:

// vite.config.js
export default {
  build: {
    rollupOptions: {
      output: {
        manualChunks: {
          vendor: ['react', 'react-dom'],
        },
      },
    },
  },
}

This configuration combined with SSG enables:

• Automatic code splitting
• Resource hashing
• Preloading critical resources

Ideal Use Cases for SSG

While SSG offers clear performance advantages, it is best suited for:

1. Websites with infrequently changing content (blogs, documentation, marketing pages)
2. Public pages requiring extreme performance
3. Pages needing high SEO scores

Hybrid Rendering Strategies

Modern frameworks support mixing SSG with other rendering modes. For example, Next.js allows:

// Page-level configuration
export async function getStaticProps() {
  // SSG logic
}

// Can also include dynamic components
function DynamicComponent() {
  const [data, setData] = useState(null);
  
  useEffect(() => {
    fetch('/api/data').then(r => r.json()).then(setData);
  }, []);

  return <div>{data}</div>;
}

This hybrid approach maintains the static nature of primary content while allowing dynamic interactions when needed.

Build-Time Data Fetching

SSG fetches all necessary data at build time, avoiding runtime delays:

// GraphQL query example
export async function getStaticProps() {
  const { data } = await client.query({
    query: gql`
      query GetAllProducts {
        products {
          id
          name
          price
        }
      }
    `,
  });

  return {
    props: {
      products: data.products,
    },
  };
}

Incremental Static Regeneration

Advanced SSG solutions like Next.js's ISR (Incremental Static Regeneration) add flexibility while maintaining static advantages:

export async function getStaticProps() {
  return {
    props: {...},
    revalidate: 60, // Regenerate every 60 seconds
  };
}

This model:

• Delivers static pages on first visit
• Updates in the background as needed
• Maintains near-instant response times

Resource Preloading Strategies

SSG can optimize resource loading order, for example:

<!-- Embed preload directives directly in generated HTML -->
<link rel="preload" href="/fonts/Inter.woff2" as="font" type="font/woff2" crossorigin>

Perfect Integration with PWAs

Static sites easily convert to Progressive Web Apps:

// workbox-config.js
module.exports = {
  globDirectory: 'out/',
  globPatterns: ['**/*.{html,js,css,woff2}'],
  swDest: 'out/sw.js',
  runtimeCaching: [{
    urlPattern: /\.(?:png|jpg|jpeg|svg)$/,
    handler: 'CacheFirst',
  }],
};

Deployment Cost Advantages

Static sites have minimal hosting costs:

• Can use free services like GitHub Pages, Netlify, Vercel
• No server maintenance required
• Automatic scaling for traffic spikes

Optimized Development Experience

SSG toolchains typically offer excellent developer experience:

• Fast hot updates
• Instant previews
• Optimized build speeds

For example, Vite's SSG support:

// vite.config.js
import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'

export default defineConfig({
  plugins: [vue()],
  ssgOptions: {
    format: 'esm',
  },
})

Security Advantages

Static sites reduce attack surfaces:

• No server-side execution
• No database connections
• Reduced injection attack risks

Modern Framework SSG Support

Mainstream frameworks provide SSG solutions:

1. Next.js: getStaticProps + getStaticPaths
2. Nuxt.js: nuxt generate
3. Gatsby: GraphQL-based data layer
4. Astro: Component-level static generation

Performance Monitoring and Optimization

Even with SSG, continuous performance monitoring is essential:

// Using web-vitals library
import {getCLS, getFID, getLCP} from 'web-vitals';

function sendToAnalytics(metric) {
  const body = JSON.stringify(metric);
  navigator.sendBeacon('/analytics', body);
}

getCLS(sendToAnalytics);
getFID(sendToAnalytics);
getLCP(sendToAnalytics);

Dynamic Enhancement of Static Sites

Enhance static pages with client-side JavaScript:

// Add dynamic features to statically generated pages
document.addEventListener('DOMContentLoaded', () => {
  if ('serviceWorker' in navigator) {
    navigator.serviceWorker.register('/sw.js');
  }
  
  // Lazy-load comment components
  const commentsSection = document.getElementById('comments');
  if (commentsSection) {
    import('./comments.js').then(module => {
      module.initComments();
    });
  }
});

Build Performance Optimization

Strategies to optimize SSG build speed:

1. Incremental builds: Only rebuild changed pages
2. Parallel generation: Utilize multi-core CPUs
3. Dependency caching: Avoid repeated processing

Example (Gatsby configuration):

// gatsby-config.js
module.exports = {
  flags: {
    FAST_DEV: true,
    PRESERVE_WEBPACK_CACHE: true,
  },
}

Content Update Strategies

Although SSG is static, multiple content update options exist:

1. Webhook-triggered rebuilds
2. Scheduled builds (e.g., hourly)
3. Client-side incremental updates

// Client-side content update check
function checkForUpdates() {
  fetch('/version.json')
    .then(res => res.json())
    .then(data => {
      if (data.buildTime > window.__BUILD_TIME__) {
        showUpdateNotification();
      }
    });
}

// Check hourly
setInterval(checkForUpdates, 60 * 60 * 1000);

SEO Advantages of Static Sites

Search engines more easily crawl and index static content:

• No JavaScript execution needed for complete content
• Response speed impacts rankings
• Clean URL structures

Inlined Resource Optimization

SSG allows inlining critical resources into HTML:

<style>
  /* Inline critical CSS */
  .hero { ... }
</style>
<script>
  // Inline critical JS
  window.__DATA__ = {...};
</script>

Modern Image Optimization

Combine SSG with automatic image optimization:

// Next.js Image component
import Image from 'next/image';

function Hero() {
  return (
    <Image
      src="/hero.jpg"
      alt="Hero Image"
      width={1200}
      height={630}
      priority
      placeholder="blur"
      blurDataURL="data:image/png;base64,..."
    />
  );
}

Multilingual Static Sites

SSG efficiently handles multilingual content:

// Statically generate multilingual paths
export async function getStaticPaths() {
  return {
    paths: [
      { params: { lang: 'en' } },
      { params: { lang: 'zh' } },
      { params: { lang: 'ja' } },
    ],
    fallback: false,
  };
}

Static API Endpoints

Some SSG frameworks support generating static APIs:

// Next.js API route
// pages/api/data.json.js
export default function handler(req, res) {
  res.status(200).json({ data: 'static' });
}

This generates a static /api/data.json endpoint at build time.