SSG vs SSR: Choosing the Right Rendering Strategy for Your App

Rendering is a trade-off between freshness and speed. Choosing the wrong strategy can either kill your SEO or frustrate your users with slow page loads.

When building a modern web application, the first big decision is: Where should the HTML be generated? The two primary contenders are Static Site Generation (SSG) and Server-Side Rendering (SSR).

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Static Site Generation (SSG)

In SSG, the HTML is generated at build time. When a user requests a page, the server simply sends a pre-made file.

Best for:

• Blogs and Documentation.
• Marketing pages.
• Portfolios.

Pros:

• Blazing Fast: No computation happens at request time.
• Highly Scalable: Files can be hosted on a CDN (edge), making them available globally.
• Secure: No active server-side logic means fewer attack vectors.

Cons:

• Build Times: As your site grows to thousands of pages, build times can increase.
• Stale Data: Changes require a new build and deploy to be visible.

Server-Side Rendering (SSR)

In SSR, the HTML is generated at request time. The server fetches data and renders the page on the fly.

Best for:

• User dashboards (personalized data).
• E-commerce with real-time inventory.
• Social media feeds.

Pros:

• Always Fresh: Data is current the moment the page loads.
• Personalization: Content can be tailored based on the user’s cookies or session.

Cons:

• Slower TTFB: The browser must wait for the server to finish rendering before receiving the first byte.
• Server Load: Every request puts a computational burden on your server.

The Hybrid Approach: The Best of Both Worlds

Modern frameworks like Astro allow for a Hybrid approach. You can mark specific pages as static and others as server-rendered within the same project.

// astro.config.mjs
export default defineConfig({
  output: 'hybrid', // Mix SSG and SSR
});

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Conclusion

Don’t treat SSG and SSR as a binary choice. Analyze your content: if it doesn’t change every minute and is the same for every user, go Static. If it’s dynamic and personalized, go Server. When in doubt, start static and move to SSR only where necessary.

Choose the right tool, deliver the best experience. 🤲