Hreflang / i18n SEO

Workflow

1. Detect hreflang tags (HTML <link>, HTTP header, or XML sitemap)
2. Run scripts/parse-hreflang.ts → validate
3. Check self-referencing, return tags, x-default
4. Verify language/region codes (ISO 639-1 + ISO 3166-1)

Common Mistakes

• ❌ Missing self-reference (<link rel="alternate" hreflang="fr" href="/fr/"> from /fr/)
• ❌ Missing return tags (A → B but not B → A)
• ❌ Invalid codes (en-UK instead of en-GB)
• ❌ HTTP/HTTPS mismatch between alternates
• ❌ Mixing trailing slashes

Implementation Options