What is x-default? Definition, syntax and when to use it

x-default is a reserved hreflang value that tells Google which page to show when none of your language or country versions matches the user’s browser settings. Google introduced it in April 2013 in a post by Webmaster Trends Analyst Pierre Far, about 16 months after hreflang itself. It takes no language code and sits in the same hreflang set as your localized URLs.

Updated: 17 October 20263 min read
Infographic: how Google applies the x-default hreflang value when no language version matches
Source: Google Search Central, Localized versions of your page

How does x-default work?

x-default works as the catch-all entry in a hreflang set: Google uses it for any language or region you have not listed. If your shop has pl-PL, de-DE and cs-CZ versions, a searcher in Hungary or a French speaker in Belgium matches none of them, and Google can show the x-default URL instead of guessing. Google Search Central notes that the language of the x-default page itself does not matter, which is why the value carries no language code.

x-default does not raise rankings. It only decides which of your existing URLs appears for unmatched users, as part of the wider hreflang mechanism.

x-default syntax: HTML, HTTP header and sitemap

You add x-default with the same method you use for the rest of your hreflang set. Google accepts 3 methods, and x-default is valid in all of them:

  • HTML head: <link rel=”alternate” hreflang=”x-default” href=”https://example.com/” />
  • HTTP header: Link: <https://example.com/>; rel=”alternate”; hreflang=”x-default”
  • XML sitemap: <xhtml:link rel=”alternate” hreflang=”x-default” href=”https://example.com/” /> inside every url entry of the set

The x-default line must appear on every version in the set, next to the self-reference and all other alternates. When the sets differ between pages, or a page does not link back, Google may ignore the annotations.

When to use x-default

Use x-default when you have a page that serves no single language or market. The 2013 Google announcement and the current documentation name these cases:

Language or country selector

A page such as example.com/choose-country/ where users pick their market is the textbook x-default target.

Auto-redirecting homepage

A root URL that sends visitors to /pl/ or /de/ based on their settings should be marked as x-default, so Google understands it is a router, not a duplicate.

Global English version

Many sites point x-default to their general English page because it serves the widest audience. This works when the English page is written for an international reader, not only for the UK or US.

SetupGood x-default target
Country selector at the rootexample.com/
Subdirectories, English as global languageexample.com/en/
ccTLDs plus a .com hubexample.com

x-default in international SEO practice

x-default matters most for sites that cover a few markets but receive traffic from many. A Polish shop with Polish, German and Czech versions still gets visitors from Slovakia, Austria and Hungary. Without x-default, Google picks whichever version it finds most relevant, often the Polish homepage, which a Slovak user cannot read. Google also warns that Googlebot usually crawls from US IP addresses without an Accept-Language header, so it mostly sees whatever your root URL returns to an unmatched visitor. A clear x-default makes that behavior intentional.

Common x-default errors

  • Pointing x-default to a URL that redirects, returns 404 or has noindex.
  • Using x-default as a language code, for example hreflang=”x-default-en”.
  • Adding x-default on the homepage only and forgetting category and product pages.
  • Declaring 2 different x-default URLs within one set.
  • Setting a canonical tag on the x-default page that points to another language version.

Combine x-default with links to every version in the visible language switcher, and avoid forced geo-redirects, which Google advises against. On large sites, declaring hreflang in the XML sitemap makes x-default easier to keep consistent.

Pro tip: Check your server logs or a crawler set to a US IP with no Accept-Language header and see what the root URL returns. In my audits, the x-default page often redirects to the Polish version for exactly that visitor, which quietly makes Polish the global default.

Need help with hreflang and x-default across several markets? See my international SEO consultancy or order a technical SEO review.

Frequently asked questions about x-default

Is x-default required in hreflang?

No, x-default is optional. Google recommends it when you have a fallback page such as a language selector or a global version for users you do not target directly.

Can x-default point to the English version?

Yes. Many sites use their general English page as x-default because it serves the widest international audience. The same URL then appears twice in the set, once as en and once as x-default.

When did Google introduce x-default?

Google announced the x-default hreflang value in April 2013 on the Webmaster Central Blog. Hreflang itself had launched in December 2011.

Does Bing support x-default?

Bing's webmaster blog does not name x-default among its signals. It lists the content-language meta tag, the lang attribute, HTTP headers, ccTLDs and server IP as its language and country signals, so add a content-language tag as well.

Related terms

International SEO · AI SEO (GEO)

Grow in every market, and get cited by AI

x-default decides what Google shows to every market you have not localized yet, which on a growing site is often most of the world. I set up hreflang and x-default for companies expanding abroad, so each visitor and each AI search answer lands on the right version.

I help SaaS and e-commerce brands win organic traffic across Europe and the US, and get their brand recommended in ChatGPT, Gemini, Perplexity and Google AI Overviews. Every project starts with a free audit of your site, your markets and your visibility in AI answers.

Write to Adrian

Have a question about this term or your SEO?

Send a short message about your website, the markets you sell in and what you want to achieve. You get a reply from me, not from a sales team.

  • Free preliminary SEO and AI visibility audit
  • Strategy for international and multilingual markets
  • Reply within one business day
Book a free call
Adrian Dąbrowiecki

Write to Adrian

Adrian Dąbrowiecki · Marketer Coffee

Tell me about your site and your goals. I usually reply within one business day.