hreflang

Definition

hreflang is a language/region annotation via <link rel="alternate" hreflang="..."> that connects equivalent pages in different languages or regions. It helps search engines serve the correct version to users.

Why it matters

• Reduces cross-language cannibalization
• Improves language/region targeting accuracy
• Helps crawlers understand your locale structure
• Improves UX (auto-redirect to correct language)
• Prevents Google from treating language variants as duplicate content
• Supports same-language regional variants (e.g., en-US vs en-GB)
• Works with canonical to fully describe page relationships

How to implement

• Declare alternates bidirectionally on every locale version
• Include an x-default fallback version
• Keep canonical self-referential; hreflang is not a canonical replacement
• Use ISO 639-1 language codes (en, zh) + optional ISO 3166-1 region (US, TW)
• Place in HTML head, HTTP header, or sitemap (sitemap for large sites)
• Ensure all alternate URLs return 200 and confirm each other
• Validate hreflang setup regularly (Search Console reports errors)

Examples

<!-- HTML head implementation -->
<link rel="alternate" hreflang="en" href="https://example.com/en/about" />
<link rel="alternate" hreflang="zh-TW" href="https://example.com/about" />
<link rel="alternate" hreflang="ja" href="https://example.com/ja/about" />
<link rel="alternate" hreflang="x-default" href="https://example.com/en/about" />
<link rel="canonical" href="https://example.com/about" /> <!-- self-referencing -->

<!-- sitemap implementation (for large multilingual sites) -->
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
        xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <url>
    <loc>https://example.com/about</loc>
    <xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/about" />
    <xhtml:link rel="alternate" hreflang="zh-TW" href="https://example.com/about" />
    <xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/en/about" />
  </url>
</urlset>

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