Missing x-default hreflang: What x-default Means and How to Add It

What hreflang x-default does

hreflang annotations tell search engines which URL serves which language or region, for example en, de or en-gb. x-default is a reserved value for the fallback: the URL to show when none of the listed languages fits the searcher. Google introduced it for language-selector and auto-redirecting home pages, and it is commonly used to point at the main (often English) version.

x-default is recommended, not required. If a site has no alternate language versions at all, there is no hreflang set for x-default to belong to, and this warning can be ignored for that site.

What bseoa flags

bseoa collects the page's <link rel="alternate" hreflang="…"> tags and reports this warning when none of them uses hreflang="x-default".

How to add x-default in HTML

Add one x-default line to the full set of alternates, and put the same set, including the page's own URL, on every language version. hreflang only works when the annotations are reciprocal:

<link rel="alternate" hreflang="en" href="https://example.com/en/pricing">
<link rel="alternate" hreflang="de" href="https://example.com/de/pricing">
<link rel="alternate" hreflang="es" href="https://example.com/es/pricing">
<link rel="alternate" hreflang="x-default" href="https://example.com/en/pricing">

x-default may point at the same URL as one of the language versions, as above, or at a separate language-selector page.

In an XML sitemap or HTTP header

For non-HTML files such as PDFs, or when you would rather not add tags to templates, put the same annotations in the sitemap:

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
        xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <url>
    <loc>https://example.com/en/pricing</loc>
    <xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/pricing"/>
    <xhtml:link rel="alternate" hreflang="de" href="https://example.com/de/pricing"/>
    <xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/en/pricing"/>
  </url>
</urlset>

Or send a Link header:

Link: <https://example.com/en/pricing>; rel="alternate"; hreflang="en",
      <https://example.com/de/pricing>; rel="alternate"; hreflang="de",
      <https://example.com/en/pricing>; rel="alternate"; hreflang="x-default"

Pick one method per URL set. Mixing methods makes conflicts hard to debug.

Common x-default mistakes

• Adding x-default only to the home page instead of every page that has language versions.
• Pointing x-default at a URL that redirects, returns 404, or canonicalizes somewhere else.
• Writing hreflang="default" or hreflang="x_default". Only x-default is valid.
• Listing x-default on one language version but not the others, so the sets don't match.