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Astro and Island Architecture – Faster Websites by Doing Less

May 5, 2022

Astro is a modern static site builder that introduced a refreshing idea: do less in the browser. While other frameworks focus on how to make client-side rendering faster, Astro focuses on not sending JavaScript unless necessary.

This idea is called island architecture.

What is island architecture?

It means you can mix multiple frameworks (React, Svelte, Vue, etc.) in your page, but only hydrate specific parts – the "islands" of interactivity. The rest of the page stays static, like pure HTML and CSS.

Benefits:

  • Less JavaScript in the browser
  • Faster load times and better Lighthouse scores
  • Easy integration of different components
  • Good for content-focused sites like blogs, docs, marketing

Getting started with Astro

Install Astro:

npm create astro@latest

Select the minimal template or one with a framework like React or Svelte.

Run dev server:

cd your-project
npm install
npm run dev

Using components

You can import components from different frameworks inside .astro files:

---
import MyReactComponent from '../components/MyReactComponent.jsx';
import Counter from '../components/Counter.svelte';
---

<html>
  <body>
    <h1>Static content is fast</h1>
    <MyReactComponent client:load />
    <Counter client:idle />
  </body>
</html>

Each interactive block is hydrated only when needed:

  • client:load runs after page loads
  • client:idle waits for browser idle time
  • client:visible waits until the component is in view

Output

Astro renders static HTML for everything else. You don’t send React or Svelte runtime if you don’t need it. That’s a big performance win.

When to use Astro?

Astro is great for:

  • Blogs
  • Documentation
  • Marketing sites
  • Sites with mostly static content and a few dynamic parts

If your app is very dynamic or needs lots of client-side interactivity, use something like Next.js or SvelteKit.

Final thoughts

Astro follows a smart idea: send less to the browser. Use components when needed. Keep the rest static. In a time where performance matters, this shift makes a lot of sense.

Astro gives you control over interactivity, framework flexibility, and great performance by default.

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