AstroComparisonBeginner · 4 min read

Static vs SSR vs Hybrid in Astro: Key Differences and Usage

In Astro, Static rendering generates HTML at build time for fast loading, SSR (Server-Side Rendering) creates HTML on each request for dynamic content, and Hybrid combines both by selectively using static and SSR pages in one project. This lets you optimize performance and interactivity based on your app's needs.

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Quick Comparison

Here is a quick overview comparing Static, SSR, and Hybrid rendering modes in Astro.

Factor	Static	SSR (Server-Side Rendering)	Hybrid
Rendering Time	At build time	On each request	Mix of build time and request time
Performance	Very fast load, no server delay	Slower due to server processing	Optimized per page
Content Freshness	Fixed at build	Always fresh	Fresh where SSR used
Use Case	Mostly static sites, blogs	Dynamic apps, user-specific data	Sites with both static and dynamic needs
Server Requirement	No server needed after build	Server required to render pages	Server needed only for SSR parts
Complexity	Simplest	More complex setup	Moderate complexity

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Key Differences

Static rendering in Astro means all HTML pages are generated once during the build process. This makes pages load very fast because they are just plain files served by any web server or CDN. However, the content cannot change until you rebuild the site.

SSR (Server-Side Rendering) generates HTML on-demand for each user request. This allows dynamic content that changes frequently or depends on user data. It requires a server to run the rendering logic every time a page is requested, which can slow down response time compared to static pages.

Hybrid mode lets you mix both approaches in one Astro project. You can choose which pages are static and which use SSR. This gives you the best of both worlds: fast static pages where possible and dynamic SSR pages where needed. It requires careful planning but offers great flexibility and performance optimization.

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Static Rendering Code Example

This Astro component generates a static page at build time with a fixed message.

astro

---
const message = 'Hello from Static Astro!';
---
<html lang="en">
  <head>
    <title>Static Page</title>
  </head>
  <body>
    <h1>{message}</h1>
  </body>
</html>

Output

<h1>Hello from Static Astro!</h1>

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SSR Equivalent Code Example

This Astro component uses server-side rendering to show the current server time on each request.

astro

---
export async function get() {
  return {
    body: JSON.stringify({ time: new Date().toISOString() })
  };
}

---
<html lang="en">
  <head>
    <title>SSR Page</title>
  </head>
  <body>
    <h1>Current Server Time: {Astro.props.time}</h1>
  </body>
</html>

Output

<h1>Current Server Time: 2024-06-01T12:00:00.000Z</h1>

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When to Use Which

Choose Static when your site content rarely changes and you want the fastest load times with minimal server costs, like blogs or documentation.

Choose SSR when your pages need to show fresh or user-specific data on every request, such as dashboards or personalized apps.

Choose Hybrid when your project has a mix of static and dynamic pages, allowing you to optimize performance and flexibility by using static rendering where possible and SSR only where necessary.

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Key Takeaways

Static rendering in Astro builds pages once for fastest load and no server needed.

SSR renders pages on each request for dynamic, fresh content but needs a server.

Hybrid mode mixes static and SSR pages to balance speed and dynamic needs.

Use static for mostly fixed content, SSR for dynamic data, and hybrid for mixed sites.