/seo-hreflang

name: seo-hreflang
description: Use when auditing or generating hreflang tags for i18n/multilingual SEO.
user-invocable: false
related-skills: seo, seo-technical, seo-sitemap

<objective> Audits or generates hreflang across all three implementation surfaces — HTML `<link>` tags, HTTP headers, and XML sitemap `<xhtml:link>` entries — validating self-referencing, return tags, x-default, and ISO 639-1 + ISO 3166-1 code correctness via `scripts/parse-hreflang.ts`. Lists the common mistakes: missing self-reference, missing return tags, invalid region codes (`en-UK` vs `en-GB`), HTTP/HTTPS mismatch between alternates, and trailing-slash inconsistency. </objective>

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

1. **HTML head**: `<link rel="alternate" hreflang="fr-FR" href="https://example.com/fr/">` 2. **HTTP Header**: `Link: <https://example.com/fr/>; rel="alternate"; hreflang="fr-FR"` 3. **XML Sitemap**: `<xhtml:link rel="alternate" hreflang="fr-FR" href="https://example.com/fr/"/>`

x-default

Required for international landing/locale selector pages:

<link rel="alternate" hreflang="x-default" href="https://example.com/">