Definition

hreflang is an attribute used in `<link rel="alternate">` tags, HTTP headers or XML sitemaps that signals the language — and optionally the geographic region — a page is intended for, helping search engines serve the appropriate localised version to the user.

Google says hreflang is a signal, not a directive: it can still choose to serve a different URL if other signals (such as the user's language settings or the canonical tag) point elsewhere. hreflang values follow the ISO 639-1 language code, optionally combined with an ISO 3166-1 Alpha 2 region code (`en`, `en-gb`, `en-au`). The reciprocal-link rule applies — every page in the language set must link back to every other page, including itself.

Examples

• UK vs US versions of a product page

  A retailer runs `example.com/uk/shoes` and `example.com/us/shoes`. Each page declares the other in hreflang: `<link rel="alternate" hreflang="en-gb" href="https://example.com/uk/shoes" />` and `<link rel="alternate" hreflang="en-us" href="https://example.com/us/shoes" />`, plus a self-reference for each.

• Default for unmatched locales

  A site adds `<link rel="alternate" hreflang="x-default" href="https://example.com/" />` so Google has a fallback URL to show users whose language and region don't match any specific localised version.

Sources

• Google Search Central — Tell Google about localized versions of your page

Related terms

• Canonical Tag
  An HTML element that tells search engines which URL is the master copy when the same or similar content exists at multiple addresses.
• Indexing
  The process by which a search engine analyses a fetched page and stores information about it so the page can later be returned in search results.

Where QueryCatch uses this

• SEO Audit
• Page Optimisation