Guides

x-default: what the value does and where to point it

x-default names the page for visitors whose language or region matches no other alternate in the cluster. Google describes the value as a recommendation: "Consider adding a fallback page for unmatched languages, especially on language/country selectors or auto-redirecting home pages." A cluster without x-default still works. Unmatched visitors then get whichever version Google picks.

The check reports a missing x-default as a warning once a cluster serves two or more languages, or two or more regions of one language. A cluster of en and en-US alone does not trigger the warning, because en already covers every English speaker.

Which URL to use

The fallback works best when it is the least specific version of the page. In a cluster with en-US, en-GB and en, x-default belongs on the en URL or on a separate language overview page. Pointing x-default at en-US while an en version exists sends unmatched visitors to a page written for one country, and the report flags the choice as xdefault-too-specific. Without an en version, en-US as x-default is fine.

<link rel="alternate" hreflang="en-US" href="https://example.com/us/" />
<link rel="alternate" hreflang="en-GB" href="https://example.com/uk/" />
<link rel="alternate" hreflang="en" href="https://example.com/en/" />
<link rel="alternate" hreflang="x-default" href="https://example.com/en/" />

Myths

Any page works as x-default only in a technical sense. The target still has to be indexable, return 200 and link back with the full set like every other member. A redirecting home page as x-default fails that test: the redirect makes the URL non-indexable, and the check reports the redirect as an error.

All members carry the same x-default. Two pages naming different x-default URLs leave Google with conflicting fallbacks, reported as xdefault-inconsistent.