--- name: seo-hreflang description: > Hreflang and international SEO audit, validation, and generation. Detects common mistakes, validates language/region codes, and generates correct hreflang implementations. Use when user says "hreflang", "i18n SEO", "international SEO", "multi-language", "multi-region", or "language tags". user-invocable: true argument-hint: "[url]" license: MIT metadata: author: AgriciDaniel version: "2.4.2" category: seo --- # Hreflang & International SEO Validate existing hreflang implementations or generate correct hreflang tags for multi-language and multi-region sites. Supports HTML, HTTP header, and XML sitemap implementations. ## Validation Checks ### 1. Self-Referencing Tags - Every page must include an hreflang tag pointing to itself - The self-referencing URL must exactly match the page's canonical URL - Missing self-referencing tags cause Google to ignore the entire hreflang set ### 2. Return Tags - If page A links to page B with hreflang, page B must link back to page A - Every hreflang relationship must be bidirectional (A→B and B→A) - Missing return tags invalidate the hreflang signal for both pages - Check all language versions reference each other (full mesh) ### 3. x-default Tag - Recommended when a selector/fallback URL exists: designates the fallback page for unmatched languages/regions - Typically points to the language selector page or English version - Only one x-default per set of alternates - Must also have return tags from all other language versions ### 4. Language Code Validation - Must use ISO 639-1 two-letter codes (e.g., `en`, `fr`, `de`, `ja`) - An **optional ISO 15924 script subtag** is the documented, official mechanism for script: `zh-Hant` (Traditional) / `zh-Hans` (Simplified). Script may combine with a region, e.g. `zh-Hans-US` is valid (language + script + region). - Common errors: - `eng` instead of `en` (ISO 639-2, not valid for hreflang) - `jp` instead of `ja` (incorrect code for Japanese) - `zh` is valid but ambiguous for script-specific pages; prefer `zh-Hans` or `zh-Hant` when targeting a script ### 5. Region Code Validation - Optional region qualifier uses ISO 3166-1 Alpha-2 (e.g., `en-US`, `en-GB`, `pt-BR`) - Format: `language-REGION` (lowercase language, uppercase region) - A **country code alone is invalid**, you cannot specify a region without a language (Google's own bad example is `be`, which is actually the Belarusian *language* code, not Belgium). - Common errors: - `en-uk` instead of `en-GB` (UK is not a valid ISO 3166-1 region code) - `EU` / `UN` as a region (not valid ISO 3166-1 values) - `es-LA` (Latin America is not a country; use specific countries) - Region without language prefix ### 5b. Geo-targeting signal hierarchy - Practical locale-signal heuristic: **ccTLD > hreflang annotations > server location/IP > addresses/language/currency/Business Profile**. Do not present this as a confirmed Google ranking order. hreflang is a **hint, not a directive**. Google **ignores** locational meta tags and HTML geotargeting attributes. - The Search Console **International Targeting report and the manual country-targeting setting were removed in 2022**, do **not** recommend setting country targeting in GSC; hreflang is the remaining lever. ### 5c. Region-specific Search units (EEA, South Africa, Türkiye) - Google documents Search experiences that exist only in certain regions (documentation added 2026-09-08; https://developers.google.com/search/docs/appearance/aggregator-features): - **EEA only:** aggregator units and supplier units (hotels, flights, ground transportation, products, and since 2026-09-18 local businesses), the ecosystem carousel, and job-site features. - **Türkiye:** places-site features (hotels, local businesses). - **South Africa:** a badge and refinement chip for travel, products, car hire, food delivery and ground transportation. - **Structured data carousels** in all three, with different query types. Eligibility and participation are documented per unit; they are not ranking signals. - When a site serves those regions with hreflang variants, note in the report whether the business is an aggregator or a direct supplier and point to the regional documentation, so the client is not surprised by a different result layout in those markets. ### 6. Canonical URL Alignment - Hreflang tags must only appear on canonical URLs - If a page has `rel=canonical` pointing elsewhere, hreflang on that page is ignored - The canonical URL and hreflang URL must match exactly (including trailing slashes) - Non-canonical pages should not be in any hreflang set ### 7. Protocol Consistency - All URLs in an hreflang set must use the same protocol (HTTPS or HTTP) - Mixed HTTP/HTTPS in hreflang sets causes validation failures - After HTTPS migration, update all hreflang tags to HTTPS ### 8. Cross-Domain Support - Hreflang works across different domains (e.g., example.com and example.de) - Cross-domain hreflang requires return tags on both domains - Use Google Search Console verification for monitoring or cross-site sitemap submission when needed - Sitemap-based implementation recommended for cross-domain setups ## Common Mistakes | Issue | Severity | Fix | |-------|----------|-----| | Missing self-referencing tag | Critical | Add hreflang pointing to same page URL | | Missing return tags (A→B but no B→A) | Critical | Add matching return tags on all alternates | | Missing x-default when fallback behavior is required | Medium | Add x-default pointing to fallback/selector page | | Invalid language code (e.g., `eng`) | High | Use ISO 639-1 two-letter codes | | Invalid region code (e.g., `en-uk`) | High | Use ISO 3166-1 Alpha-2 codes | | Hreflang on non-canonical URL | High | Move hreflang to canonical URL only | | HTTP/HTTPS mismatch in URLs | Medium | Standardize all URLs to HTTPS | | Trailing slash inconsistency | Medium | Match canonical URL format exactly | | Hreflang in both HTML and sitemap | Low | Choose one method (sitemap preferred for large sites) | | Language without region when needed | Low | Add region qualifier for geo-targeted content | ## Implementation Methods ### Method 1: HTML Link Tags Best for: Sites with <50 language/region variants per page. ```html ``` Place in `` section. Every page must include all alternates including itself. ### Method 2: HTTP Headers Best for: Non-HTML files (PDFs, documents). ``` Link: ; rel="alternate"; hreflang="en-US", ; rel="alternate"; hreflang="fr", ; rel="alternate"; hreflang="x-default" ``` Set via server configuration or CDN rules. ### Method 3: XML Sitemap (Recommended for large sites) Best for: Sites with many language variants, cross-domain setups, or 50+ pages. See Hreflang Sitemap Generation section below. ### Method Comparison | Method | Best For | Pros | Cons | |--------|----------|------|------| | HTML link tags | Small sites (<50 variants) | Easy to implement, visible in source | Bloats ``, hard to maintain at scale | | HTTP headers | Non-HTML files | Works for PDFs, images | Complex server config, not visible in HTML | | XML sitemap | Large sites, cross-domain | Scalable, centralized management | Not visible on page, requires sitemap maintenance | ## Hreflang Generation ### Process 1. **Detect languages**: Scan site for language indicators (URL path, subdomain, TLD, HTML lang attribute) 2. **Map page equivalents**: Match corresponding pages across languages/regions 3. **Validate language codes**: Verify all codes against ISO 639-1 and ISO 3166-1 4. **Generate tags**: Create hreflang tags for each page including self-referencing 5. **Verify return tags**: Confirm all relationships are bidirectional 6. **Add x-default**: Set fallback for each page set 7. **Output**: Generate implementation code (HTML, HTTP headers, or sitemap XML) ## Hreflang Sitemap Generation ### Sitemap with Hreflang ```xml https://example.com/page https://example.com/fr/page ``` Key rules: - Include the `xmlns:xhtml` namespace declaration - Every `` entry must include ALL language alternates (including itself) - Each alternate must appear as a separate `` entry with its own full set - Split at whichever comes first: 50,000 URLs or 50MB uncompressed per sitemap file ## Output ### Hreflang Validation Report #### Summary - Total pages scanned: XX - Language variants detected: XX - Issues found: XX (Critical: X, High: X, Medium: X, Low: X) #### Validation Results | Language | URL | Self-Ref | Return Tags | x-default | Status | |----------|-----|----------|-------------|-----------|--------| | en-US | https://... | ✅ | ✅ | ✅ | ✅ | | fr | https://... | ❌ | ⚠️ | ✅ | ❌ | | de | https://... | ✅ | ❌ | ✅ | ❌ | ### Generated Hreflang Tags - HTML `` tags (if HTML method chosen) - HTTP header values (if header method chosen) - `hreflang-sitemap.xml` (if sitemap method chosen) ### Recommendations - Missing implementations to add - Incorrect codes to fix - Method migration suggestions (e.g., HTML to sitemap for scale) ## Cultural Adaptation Assessment When analyzing a multi-language site, go beyond technical hreflang validation to assess whether the content is culturally adapted for each target market. Load `references/cultural-profiles.md` for pre-built profiles (DACH, Francophone, Hispanic, Japanese). **Assessment steps:** 1. Identify all language versions and their target markets 2. Load the relevant cultural profile(s) 3. Check CTAs match cultural expectations (direct vs indirect) 4. Check trust signals are locale-appropriate (certifications, legal pages) 5. Check for foreign brand references on localized pages 6. Check number/date/currency formatting consistency 7. Flag cultural adaptation issues as Medium severity **Output:** Cultural Adaptation Score per language version (0-100) with specific findings. ## Content Parity Audit **Command:** `/seo hreflang audit ` Audit content parity across all language versions of a site or local content directory. Load `references/content-parity.md` for the full parity matrix and scoring methodology. **What it checks:** - Page existence across all declared languages - Section structure equivalence (H2/H3 count) - SEO element parity (title, meta, schema localization) - Word count ratio validation (DE should be 25-35% longer than EN, JA 10-25% shorter) - Freshness tracking (stale translations detected via timestamps) - Cultural marker scanning (foreign brands, wrong legal references, untranslated elements) **Output:** Parity matrix table with per-page scores and prioritized action items. ## Locale Format Validation Load `references/locale-formats.md` for number, date, currency, address, and phone format reference tables per locale. **Checks:** - Number format consistency (e.g., "1,000.00" should be "1.000,00" on de-DE pages) - Date format matches locale expectations - Currency symbols and placement correct for target market - Phone numbers use international format with correct country code ## Reference Files Load on-demand as needed (do NOT load all at startup): - `references/cultural-profiles.md`: DACH, Francophone, Hispanic, Japanese cultural adaptation profiles - `references/locale-formats.md`: Number, date, currency, address, phone format tables per locale - `references/content-parity.md`: Content parity audit methodology and scoring - `references/machine-translation-qa.md`: Flags unreviewed machine translation, which Google's spam policy treats as scaled content abuse ## Error Handling | Scenario | Action | |----------|--------| | URL unreachable (DNS failure, connection refused) | Report the error clearly. Do not guess site structure. Suggest the user verify the URL and try again. | | No hreflang tags found | Report the absence. Check for other internationalization signals (subdirectories, subdomains, ccTLDs) and recommend the appropriate hreflang implementation method. | | Invalid language/region codes detected | List each invalid code with the correct replacement. Provide a corrected hreflang tag set ready to implement. | | Cultural profile not available for language | Use the Default Profile checklist from cultural-profiles.md. Note that assessment is based on general guidelines, not a pre-built profile. | | Content parity directory empty | Report that no content files were found. Suggest verifying the directory path or providing a URL for live site analysis. |