How to build a multilingual sitemap that search engines can use

Source of truth

Start with the site-owned sitemap

Your application sitemap should contain every canonical public URL, including dynamic pages. Treat it as the source of truth for what is live, indexable, and worth discovering.

• Use the same public origin as the pages.
• Include updated timestamps from the source record when possible.
• Do not include preview, authenticated, or redirected URLs.

export default function sitemap() {
  return publicPages.map((page) => ({
    url: `https://example.com${page.path}`,
    lastModified: page.updatedAt,
  }));
}

Language versions

Add localized URLs and alternates

Next.js can emit language alternate links from sitemap entries. For each source page, map the complete set of published language URLs and keep the map stable across every version.

• Use the same content identity across languages.
• Exclude a locale until its page is actually published.
• Keep the canonical URL and sitemap URL consistent.

export default async function sitemap() {
  const products = await getPublicProducts();
  const locales = ["en", "fr", "de"];

  return products.flatMap((product) => locales.map((locale) => ({
    url: `https://example.com/${locale}/products/${product.slug}`,
    lastModified: product.updatedAt,
    alternates: {
      languages: Object.fromEntries(locales.map((language) => [
        language, `https://example.com/${language}/products/${product.slug}`
      ])),
    },
  })));
}

Large sites

Split sitemaps without splitting ownership

Large sites can use sitemap indexes and shards by locale, content type, or record range. The index should point to reachable child sitemaps, and each child should remain below the search engine limits.

• Use deterministic shard names.
• Keep one clear index route.
• Monitor child sitemap response codes and XML validity.

Altified workflow

Use the supplemental sitemap for translated discovery

Altified can generate a supplemental sitemap containing additional-language URLs from your existing site sitemap. It does not replace the site-owned sitemap and it does not add hreflang to pages by itself; your application still needs reciprocal metadata.

• Keep /sitemap.xml complete and site-owned.
• Publish /altified-sitemap.xml after target locales and routes exist.
• Submit both sitemaps or list both in robots rules.