hreflang x-default
The hreflang value marking the fallback page for users whose language or region does not match any specified alternate.
Internationalrel=alternate hreflang
hreflang
An annotation declaring alternate language or regional versions of a page, so search engines serve the appropriate one to each user.
In full
hreflang can be implemented in the HTML head, in HTTP headers, or in XML sitemaps, and its cardinal rule is reciprocity: every page in a set must reference every other, including itself. Values use ISO 639-1 language codes optionally combined with ISO 3166-1 Alpha-2 region codes — `en-GB`, `es-MX` — and using a country code alone is invalid. It is a targeting signal, not a ranking signal or a redirect: it swaps which version ranks, it does not create rankings.
Example
A page set of `en-GB`, `en-AU`, `en-US` and `x-default` versions each list all four URLs, so Australian users receive the AU page.
Related terms
International SEO
Structuring and optimising a site so the right language and country version is served to the right audience in each market's search results.
Multilingual sitemaps
XML sitemaps carrying `xhtml:link rel="alternate" hreflang` annotations, an alternative to placing hreflang in page head markup.
Geo-targeting
Signalling which country a site or section is intended for, through ccTLD choice, hreflang region codes, server location, local links and…
Canonicalization
The process by which a search engine groups duplicate or near-duplicate URLs into a cluster and picks one representative URL to index and…
Where to read more
- Localized Versions of Your Pages (hreflang) · Documentation · developers.google.com
- The Web Almanac — SEO Chapter · Study · almanac.httparchive.org