SEO audit — multilocale website

You're auditing a website that serves content in multiple languages (typically Indonesian + English, sometimes Chinese, Malay, etc.) for the 6 multilocale-specific SEO mistakes that hurt rankings.

Examples use Next.js. Same concepts apply to any framework — replace app/ with the equivalent route structure.

The 6 checks

1. Hreflang tags missing or wrong

What goes wrong: Google doesn't know which language version to show in which country → wrong language served to users → bounces + ranking damage.

What to check:

• Every page that exists in multiple languages should declare hreflang alternates in metadata.
• For Next.js: in generateMetadata or metadata export, look for alternates: { languages: { ... } }.
• The alternates must be RECIPROCAL: page A says "English version is at /en/page", and the English page must say "Indonesian version is at /id/page" (or whatever the path is).
• Include x-default pointing to the fallback locale (usually the most-traffic version).
• Use proper language codes: id for Indonesian, en for English, id-ID only when targeting Indonesia specifically.

Sample what right looks like:

alternates: {
  canonical: 'https://example.com/id/about',
  languages: {
    'id': 'https://example.com/id/about',
    'en': 'https://example.com/en/about',
    'x-default': 'https://example.com/id/about',
  },
}

2. Sitemap missing language alternates

What goes wrong: sitemap.xml lists pages but doesn't link locale variants → Google indexes them as separate, unrelated pages.

What to check:

• Read the sitemap source (Next.js: app/sitemap.ts).
• For each multilingual page, the sitemap entry should include alternates.languages with all variants.
• Check that BOTH locales appear in the sitemap, not just the default.

Sample correct entry:

{
  url: 'https://example.com/id/page-1',
  alternates: {
    languages: {
      id: 'https://example.com/id/page-1',
      en: 'https://example.com/en/page-1',
    },
  },
}

3. Canonical URL inconsistent or self-referential mistake

What goes wrong: every page version points canonical to the SAME URL → Google sees them as duplicates and indexes only one. Or every page points canonical to itself → no consolidation signal.

What to check:

• For each language variant: canonical should point to ITSELF (the locale version). Not to the default-language version.
• The hreflang and canonical work together: canonical = "this is the authoritative URL for THIS language", hreflang = "here are the other-language equivalents".

4. Locale routing trapped behind JS / not server-rendered

What goes wrong: locale chosen via client-side JavaScript only → Googlebot sees one default version → other locales never indexed.

What to check:

• Are language variants rendered server-side? URL pattern like /id/, /en/, or id.example.com, en.example.com — these are crawlable.
• Pure JS toggles (<button onClick={setLocale('en')}>) without URL change = invisible to Google.
• For Next.js: i18n routing config or route groups ((id), (en)) create proper crawlable URLs.

5. Structured data (JSON-LD) missing or wrong language

What goes wrong: JSON-LD describes content in default language only → Google doesn't know rich snippets exist for other locales → loses rich-result eligibility.

What to check:

• Every public page should have JSON-LD. For each multilingual page, JSON-LD's inLanguage field should match the page's locale.
• Different page types need different schema: Article, Product, TouristTrip, Organization, BreadcrumbList.
• Example check: open the rendered HTML for the Indonesian version of an article. Find <script type="application/ld+json">. Confirm "inLanguage": "id".
• Common mistake: copy-pasted JSON-LD across locales without updating inLanguage and content fields.

6. Locale-aware redirects from old URLs missing

What goes wrong: site relaunch changed URL structure (e.g. /about → /id/about). Old URLs return 404 → Google de-indexes → traffic drops.

What to check:

• For each old URL pattern, is there a redirect to the locale-aware new URL?
• For Next.js: check redirects() in next.config.mjs, or middleware-based redirects.
• Use 301 (permanent) for SEO consolidation, not 302 (temporary).
• Detect locale from header (Accept-Language) or geo (your CDN's country header) for the redirect destination, with a stable fallback.

How to deliver the report

# Multilocale SEO audit — [site name]

## Coverage summary
- Pages audited: N
- Locales detected: [id, en, ...]
- Pages missing hreflang: N
- Pages with broken canonical: N

## Critical issues
1. [issue] — Pages affected: [list or count]. Evidence: [file:line]. Fix: [concrete step].

## Warnings
[same format]

## Verified clean
- [check]

End with one of:

• "Critical: [N]. Mau gue bantu fix yang #1 dulu (biasanya hreflang reciprocity), atau lo review dulu?"
• "Critical: 0, warnings: [N]. Mau lanjut ke content audit (/skill seo-content-audit)?"

Constraints

• Validate hreflang reciprocity by actually checking BOTH directions — A→B and B→A.
• Don't recommend installing next-i18next or any tool unless the codebase actually needs it. Check what's already there.
• For sites with only one language: skip this skill, recommend seo-content-audit instead.