# Hreflang — Audit Rules & Best Practices (March 2026) > Author: Laurent Rochetta | BMAD+ SEO Engine v2.0 ## What is Hreflang? `hreflang` tells search engines which language/region version of a page to serve. Errors cause wrong language indexing, duplicate content penalties, and lost organic traffic. --- ## Implementation Methods | Method | Best For | Max Pages | |--------|----------|-----------| | `` in `` | Small sites (<50 pages) | ~50 | | HTTP header `Link:` | Non-HTML files (PDFs) | ~50 | | Sitemap `` | Large sites (50+) | Unlimited | > **Recommendation**: Use sitemap for sites with 50+ pages. HTTP headers for non-HTML resources. --- ## Validation Rules ### Rule 1: Valid Language Codes - Use **ISO 639-1** (2-letter): `en`, `fr`, `de`, `es`, `ja`, `zh` - Optional **ISO 3166-1 Alpha-2** for region: `en-US`, `en-GB`, `fr-FR`, `fr-CA`, `pt-BR` - **Case insensitive** but convention is lowercase lang, uppercase country | ✅ Valid | ❌ Invalid | Why | |---------|-----------|-----| | `en` | `english` | Must be ISO 639-1 | | `fr-FR` | `fr-FRA` | Country must be 2-letter | | `zh-Hans` | `cn` | `cn` is not a valid language code | | `x-default` | `default` | Must use exact `x-default` | ### Rule 2: Self-Referencing (MANDATORY) Every page MUST include a hreflang tag pointing to itself. ```html ``` **Error if missing**: Google may ignore all hreflang tags on that page. ### Rule 3: Return Tags (MANDATORY) If page A links to page B with hreflang, page B MUST link back to page A. ``` Page A (en) → hreflang="fr" → Page B (fr) Page B (fr) → hreflang="en" → Page A (en) ← MANDATORY ``` **Error if missing**: Called "orphan hreflang" — Google ignores the one-way tag. ### Rule 4: x-default (STRONGLY RECOMMENDED) Designate a fallback page for users whose language/region doesn't match any variant. ```html ``` Common choices for x-default: - Language selector/redirect page - English version (most common) - Homepage of the main domain ### Rule 5: Canonical + Hreflang Consistency - Each hreflang URL **must be the canonical version** (not a redirect, not a URL with parameters) - If a page has `rel="canonical"` pointing elsewhere, hreflang tags on that page are **ignored** - Canonical and hreflang must agree: don't have hreflang point to a URL that canonicalizes to a different URL ### Rule 6: Absolute URLs Only ```html ``` ### Rule 7: No Hreflang on Non-200 Pages - Don't include hreflang tags on pages that return 3xx, 4xx, or 5xx - Don't point hreflang to pages that redirect --- ## Common Error Patterns ### Error 1: Missing Return Tags **Symptom**: hreflang is configured on the main language but not on alternate versions. **Fix**: Add reciprocal hreflang tags on ALL language variants. ### Error 2: Wrong Canonical + Hreflang **Symptom**: Page A hreflang → Page B, but Page B canonical → Page C. **Fix**: Align canonical and hreflang targets. ### Error 3: Missing Self-Reference **Symptom**: Page lists other language versions but not itself. **Fix**: Add `hreflang` tag with the current page's own language/URL. ### Error 4: Inconsistent URLs **Symptom**: hreflang uses `http://` but site is on `https://`, or trailing slash mismatch. **Fix**: Use exact canonical URL (protocol, www/non-www, trailing slash). ### Error 5: Language vs Region Confusion **Symptom**: Using `hreflang="fr"` for France and `hreflang="fr"` for Canada. **Fix**: Use `hreflang="fr-FR"` and `hreflang="fr-CA"` to differentiate. ### Error 6: Missing x-default **Symptom**: Users in unsupported regions see random language version. **Fix**: Add `x-default` pointing to language selector or English version. --- ## Sitemap Implementation (Recommended for 50+ pages) ```xml https://example.com/en/page ``` --- ## Audit Checklist | # | Check | Priority | |---|-------|----------| | 1 | All hreflang language codes are valid ISO 639-1 | 🔴 Critical | | 2 | All hreflang country codes are valid ISO 3166-1 | 🔴 Critical | | 3 | Every page has self-referencing hreflang | 🔴 Critical | | 4 | All hreflang tags have return tags | 🔴 Critical | | 5 | All hreflang URLs are absolute | 🔴 Critical | | 6 | x-default is specified | 🟠 High | | 7 | Hreflang URLs match canonical URLs | 🟠 High | | 8 | No hreflang on non-200 pages | 🟠 High | | 9 | No hreflang pointing to redirecting URLs | 🟠 High | | 10 | Consistent protocol (https) and www/non-www | 🟡 Medium | | 11 | Language/region differentiation correct | 🟡 Medium | | 12 | Sitemap implementation for 50+ pages | 🟡 Medium |