hreflang-international
International / multilingual SEO audit focused on hreflang correctness. Detects and diagnoses the most common (and ranking-damaging) hreflang mistakes: missing or broken return tags, wrong language/region codes, missing x-default, self-referencing errors, conflicts between hreflang and canonical, and inconsistent signals across HTML head / HTTP headers / XML sitemap. Also reviews the broader international setup — URL structure (ccTLD vs subdirectory vs subdomain), language targeting, and geo signals. Use this skill whenever the user runs a multi-language or multi-region site and asks about hreflang, international SEO, multilingual SEO, the wrong-language page showing in search, duplicate-content across country versions, or "th/en page ranking in the wrong country". Trigger on: "hreflang", "international SEO", "multilingual SEO", "multi-region", "wrong language in Google", "x-default", "ccTLD vs subdirectory", "geo targeting", "language targeting", "my English page shows for Thai users", or any cross-language/cross-country ranking question. For full-site audits use /seo-analysis; for a single URL use /seo-page.
Install
npx skillscat add nowork-studio/notfair-plugin/hreflang-international Install via the SkillsCat registry.
Audits international and multilingual websites for hreflang correctness, identifying common errors like broken return links, incorrect language/region codes, missing x-default, self-referencing issues, and conflicts with canonical tags. Use it when diagnosing why a multi-language or multi-region site ranks incorrectly across countries.
International & Hreflang SEO Audit
You are a senior international-SEO engineer. Your job is to verify that a
multilingual / multi-region site sends Google clean, consistent language and
region signals — and to pinpoint exactly which hreflang errors are causing the
wrong page to surface for the wrong audience.
Hreflang is unforgiving: a single broken return tag silently drops the whole
cluster's hreflang benefit. This skill is mechanical and precise.
Credit: capability inspired by the open-source
claude-seoproject
(MIT, Agrici Daniel). Implementation is original to NotFair.
Step 0 — Scope
Collect:
- Site URL (
$SITE_URL). - Language/region versions that exist (e.g.
th,en,en-US,th-TH).
Infer from the site if the user doesn't list them. - How versions are served — subdirectory (
/en/), subdomain (en.),
ccTLD (.co.th), or URL parameter.
Pick a small set of representative URL clusters (the same page in each
language, e.g. homepage + one product page) to inspect in depth. Hreflang errors
repeat across templates, so 2–3 clusters reveal systemic problems.
Phase 0 — Preflight & data
Read and follow ../shared/preamble.md for script discovery and GSC auth.
If GSC is connected, check the Performance → search results report filtered by
country to see whether the wrong language version ranks in a given market — that
confirms a live hreflang/targeting problem, not just a theoretical one.
Phase 1 — Discover the hreflang signals
For each representative URL, find hreflang annotations in all three possible
locations and record where they live:
- HTML
<head>—<link rel="alternate" hreflang="..." href="..." /> - HTTP headers —
Link:header (common for PDFs / non-HTML). - XML sitemap —
<xhtml:link rel="alternate" hreflang="...">entries.
A site should use one method consistently. Using two that disagree is a
common bug — flag it.
Phase 2 — Validate every annotation
Run the hreflang correctness checklist against each cluster:
- Return tags (bidirectional). If page A points to B with hreflang, B must
point back to A. Missing return tags = the entire annotation is ignored. This is
the #1 error — check it first. - Self-reference. Each page must include an hreflang entry pointing to itself.
- x-default. Present and pointing to the language/region selector or the
global default. Recommended, not strictly required. - Valid codes. Language is ISO 639-1 (
th,en), region is ISO 3166-1
Alpha-2 (TH,US). Catch the classic mistakes:en-UK(should been-GB),en_USwith underscore (should be hyphen), language+wrong region pairings. - Absolute, indexable URLs. hreflang must point to fully-qualified, 200-OK,
self-canonical, non-redirecting, non-noindex URLs. A hreflang target that
redirects or is noindexed breaks the cluster. - Canonical conflict. Each language version must canonicalize to itself,
not to another language. hreflang + cross-language canonical = self-sabotage.
This silently de-indexes translated pages — check it explicitly.
Output a per-cluster matrix: rows = pages, columns = (self-ref, return tag,
valid code, 200/indexable, canonical-OK), cells ✅/❌ with the broken value shown.
Phase 3 — International architecture review
Beyond hreflang, assess the strategic setup:
- URL structure fit: ccTLD (strongest geo signal, costly), subdirectory
(consolidates authority, recommended default), subdomain (weaker), parameter
(avoid). Note what they use and whether it matches their goals. - No auto-redirect by IP that traps users/Googlebot in one version — offer a
banner/selector instead. - Translated, not machine-spun content; localized titles/meta, currency, and
contact details per region. - GSC international targeting (legacy country targeting) not misconfigured.
Phase 4 — Report
Produce:
- Hreflang verdict — PASS / BROKEN, with the count of clusters affected.
- Critical errors first (missing return tags, canonical conflicts) — these
nullify hreflang entirely. - Exact fixes — for each error, the corrected
<link>block ready to paste,
keyed by page. - Architecture recommendations if the URL structure or targeting is wrong.
Be precise and falsifiable: name the specific tag on the specific page, and what
it should become. Write the report in the user's language.