Astro SEO Guide

Complete guide to building SEO-friendly applications with Astro. Learn best practices, common pitfalls, and actionable recommendations.

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Astro

Static Site Generator

Easy SEO SetupOfficial Site

SEO Friendliness

Technical SEO capability

5/5
Strong

Performance

Runtime and delivery efficiency

5/5
Strong

Ecosystem

Community, plugins, tooling

3/5
Good

Primary Rendering

SSG, Partial Hydration

Key SEO Considerations

1

A content-driven web framework designed for building the world's fastest websites.

2

Its defining feature is "Islands Architecture," rendering pages with zero client-side JavaScript by default.

3

It is framework-agnostic, allowing you to use components from React, Vue, Svelte, and more.

4

This "HTML-first, JS-optional" approach results in unparalleled performance and Core Web Vitals scores.

5

Best suited for content-rich sites, not complex, state-intensive web applications.

Core Architecture

The Web Framework for Content-Driven Websites

Astro is designed for building fast, content-driven sites like blogs and marketing pages. Its core philosophy is to deliver the best performance by sending as little JavaScript as possible. It is UI-framework-agnostic, allowing you to use React, Vue, Svelte, etc., components side-by-side.

Islands Architecture

Zero JS by Default

Astro's key innovation is "Islands Architecture." It renders pages to static HTML, and then "hydrates" only the specific interactive components ("islands") that require JavaScript. This "zero JS by default" approach leads to world-class performance and exceptional Core Web Vitals scores, a major SEO advantage.

SEO Implementation

Simple and Effective

SEO is managed through a layout-based system, where a base layout component accepts props like title and description to populate head tags. The official @astrojs/sitemap integration automates sitemap generation.

Hydrating Islands

Astro gives fine-grained control over when interactive components load JavaScript using client directives like client:visible (hydrates when the component enters the viewport), keeping the JS footprint to an absolute minimum.

Actionable Recommendations

  • Choose Astro when the primary goal is to deliver content quickly and efficiently.
  • Think in "islands": build static HTML first, then identify the minimal components that need to be interactive.
  • Leverage the official integrations for common tasks like sitemaps.
  • Use Content Collections for any site with Markdown or MDX-based content to ensure it is structured and type-safe.

International SEO

International SEO Fundamentals

When targeting multiple countries or languages, proper international SEO ensures search engines serve the right content to the right audience. This involves URL structure, hreflang tags, and language detection.

  • URL Structure Options: Choose between subdirectories (/en/, /fr/), subdomains (en.site.com), or parameters (?lang=en). Subdirectories are typically recommended for most sites.
  • Hreflang Tags: HTML attributes that tell search engines about language and regional variations of your pages. Format: <link rel="alternate" hreflang="en-US" href="..." />
  • Language vs Locale: Use language codes (en) for language targeting, or locale codes (en-US, en-GB) for region-specific content.

Implementing International SEO in Astro

Astro provides flexible routing and manual control over i18n implementation, perfect for static, content-focused multilingual sites.

  • Routing Strategy: Use Astro's file-based routing with language directories: src/pages/en/about.astro and src/pages/fr/about.astro. Alternatively, use dynamic routes with language parameters.
  • Adding Hreflang: Add hreflang tags in your layout component's <head> section. Since Astro generates static HTML, hreflang tags are baked into the output.
  • Recommended Tools: astro-i18next (popular integration), astro-i18n (lightweight), or manual implementation with Content Collections for structured content.
  • Code Example:
    ---
// src/layouts/Layout.astro
const { title, description, lang = 'en', alternates } = Astro.props;
---
<html lang={lang}>
  <head>
    <meta charset="UTF-8" />
    <title>{title}</title>
    <meta name="description" content={description} />
    
    {alternates && alternates.map(({ hreflang, href }) => (
      <link rel="alternate" hreflang={hreflang} href={href} />
    ))}
  </head>
  <body>
    <slot />
  </body>
</html>

---
// src/pages/en/about.astro
import Layout from '@/layouts/Layout.astro';

const alternates = [
  { hreflang: 'en', href: 'https://site.com/en/about' },
  { hreflang: 'fr', href: 'https://site.com/fr/about' },
  { hreflang: 'x-default', href: 'https://site.com/en/about' }
];
---
<Layout title="About Us" lang="en" alternates={alternates}>
  <h1>About Us</h1>
</Layout>

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