Hreflang tag: what is it for and how do you declare it?

What is the hreflang tag?

Google recommends telling it about these versions so that it can send each user to the most appropriate one (Tell Google about localized versions of your page, Google Search Central, updated on September 21, 2026). Without a declaration, it can find some of them on its own. It is a technical setting of search engine optimization.

On December 5, 2011, Google extended rel="alternate" hreflang to translated and multi-regional content, to consolidate the signals of these pages and serve the appropriate URL.

Two common beliefs need correcting. Google uses neither hreflang nor the HTML lang attribute to find out the language of a page: its algorithms work it out from the visible content. And a translation is not duplicate content: localized versions only count as duplicates if their main content is not translated.

When do you need hreflang tags?

Hreflang tags are useful as soon as a page exists in several versions, for different languages or countries. Google names three situations.

A multilingual site offers several languages; a multi-regional site targets several countries. In both cases, Google recommends a separate URL for each version rather than content that changes based on a cookie or browser settings (Managing multi-regional and multilingual sites, updated on December 10, 2025). Googlebot generally crawls from the United States, without an Accept-Language header: a page that adapts to the browser language may not be crawled in full.

Google also advises against automatically redirecting users based on the language it assumes they speak. Links to the other versions let them choose. The name of a folder (/en/) or of a subdomain is not enough either: the link between a page and its audience has to be declared.

Choosing the structure (country domain, subdomain, subdirectory) falls under international SEO, a broader topic than hreflang.

How do you write a hreflang tag?

For hreflang in SEO, each version carries the same list of tags: one per version, the page itself included. Here are the three lines served on October 19, 2026 in the <head> of the French elev8-lab.fr article on the canonical URL:

• <link rel="alternate" hreflang="fr" href="https://elev8-lab.fr/seo/url-canonique/">
• <link rel="alternate" hreflang="en" href="https://elev8-lab.fr/en/seo/canonical-url/">
• <link rel="alternate" hreflang="x-default" href="https://elev8-lab.fr/en/seo/canonical-url/">

The English version carries the same three tags, in a different order (en, fr, x-default): the list is identical from one version to the other. Four Google rules apply:

• Self-reference: the page appears in its own list.
• Reciprocity: if page A lists page B, page B must list page A. Otherwise, Google ignores the tags of both pages, which stops a third-party site from declaring itself a variant of yours.
• Full URLs: with the protocol (https://example.com/fr/), never //example.com/fr/ or /fr/. The versions can be on different domains.
• Plain tag: <link> elements in a well-formed <head>, with no media attribute in the same tag.

Which language and region codes should you use?

The hreflang value is an ISO 639-1 language code, followed if needed by an ISO 3166-1 alpha-2 country code: fr, fr-BE, en-GB. Google only accepts these two standards, plus the ISO 15924 script codes (zh-Hant, zh-Hans), and ignores case.

For several variants of the same language, Google advises a generic page for the language alone (en), which can be one of the regional pages. The WHATWG HTML standard, for its part, accepts any BCP 47 tag, es-419 included: a code that is valid in HTML can therefore be rejected by Google.

What is x-default for?

x-default designates the page to show when no declared language or country matches the browser settings. Google introduced it on April 10, 2013 (Google Search Central blog post), with support also announced by Yandex, for country selectors and home pages that adapt their content.

HTML tag, sitemap or HTTP header: which method should you choose?

Google accepts three methods, which it treats as equivalent. Combining them is possible but adds nothing and makes maintenance harder: one is enough.

In an XML sitemap, the <urlset> root declares the xmlns:xhtml="http://www.w3.org/1999/xhtml" namespace. Each <url> then lists all the versions, its own included, in the order you want. For the French version:

• <loc>https://example.com/fr/</loc>
• <xhtml:link rel="alternate" hreflang="fr" href="https://example.com/fr/"/>
• <xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/"/>

These child elements do not count toward a sitemap’s URL limit. For a PDF, the header takes this form: Link: <https://example.com/fr/guide.pdf>; rel="alternate"; hreflang="fr", <https://example.com/en/guide.pdf>; rel="alternate"; hreflang="en". The IETF’s RFC 8288 (October 2017) makes hreflang, in this header, a language hint that does not replace the Content-Language header.

How do you combine hreflang and the canonical tag?

Each version keeps its own canonical URL, in its own language. Google requires it: with hreflang, the canonical page must be in the same language, or in the best possible substitute language if none exists (How to specify a canonical URL, updated on July 10, 2026).

The same page adds two points. A rel="canonical" tag that carries an hreflang, lang, media or type attribute is not used to choose the canonical. And among its canonicalization signals, Google favors URLs that are part of an hreflang cluster. For very similar pages in the same language, intended for several countries, Google advises choosing one version and combining rel="canonical" with hreflang.

Example: the hreflang setup of elev8-lab.fr

Since September 26, 2026, elev8-lab.fr has published an English version under /en/. French stays at the root, English sits in a subdirectory, and each piece of content is translated page by page. The tags come from the site’s theme code, with no multilingual plugin.

Two choices were made that day. The codes have no region (fr, en), because the site is aimed at French and English speakers in all countries. And x-default designates the English version.

The public HTML recorded on October 19, 2026 confirms it: lang="fr-FR" on the French page, lang="en-US" on the English one, and on each a canonical to itself and the three tags shown above. The home page, the SEO pillar page, the blog, the About page and the legal notice follow the same pattern.

The code follows four principles:

• A single method: the <link> tags in the <head>. The Yoast SEO sitemaps contain no xhtml:link.
• A link entered on one side only: in the editor, the English content states which French content it translates. The code checks this link in both directions before outputting the tags: reciprocity does not depend on entering it twice.
• One translation per piece of content: an English piece targets only one French piece. A second link to the same content produces no hreflang, and the WordPress editor flags it.
• No redirect based on the browser language: an FR / EN button leads to the equivalent page. This button is an <a hreflang="en" lang="en"> link, whose hreflang attribute remains purely advisory under the HTML standard.

This figure describes the setup, not its effect: no Search Console data on the English pages is published here.

Which pages have no hreflang?

Some pages of the site deliberately have no hreflang tag. The code does not output any in these cases, and the checks of October 19, 2026 confirm it for the first three.

Is an x-default pointing to English compliant?

Yes. Google accepts x-default on any page, and elev8-lab.fr pointed it to the English version. For a user whose language matches neither fr nor en, the declared fallback page is therefore the English page.

Which errors cause hreflang tags to be ignored?

Hreflang tags that break a Google rule are ignored or have no effect. Here are the errors to look out for.

In every tag, replace a URL that is the subject of a 301 redirect with its destination, and remove any URL that returns a 404 error. After a site migration, check the hreflang tags along with the redirects: every URL change affects all the versions in the cluster.

The Search Console “International Targeting” report is deprecated and targeting a country through this setting is no longer supported, but Google continues to use hreflang tags (Search Console Help).

How do you test your hreflang tags?

Testing hreflang tags means checking, page by page and then across the whole site, that each version lists all the others and lists itself. Since the Search Console international report is deprecated, this check is done by hand or with tools.

1. Read the served <head>: view the source code, or run curl -s https://example.com/fr/ | grep hreflang, then check the URLs and codes.
2. Open each version listed: the same list must appear there, with the return tag.
3. Run the page through a testing tool: Google lists the Merkle hreflang tag testing tool and Aleyda Solis’s hreflang tags generator, two third-party tools that it does not maintain or check.
4. Crawl the site: Screaming Frog SEO Spider sorts errors in a Hreflang tab with 13 filters, including “Missing Return Links”. Its hreflang audit tutorial, modified on January 10, 2025, states that this feature requires a paid licence.
5. Compare canonicals: URL Inspection in Google Search Console shows the declared canonical and the one Google selected. A mismatch on a language version needs fixing.
6. Check every pair: on elev8-lab.fr, a read-only script checks each of the 85 FR / EN pairs in production, rather than a sample.

Elev8 Lab has no commercial relationship with the vendors mentioned. An hreflang cluster needs maintenance: every new translation, every changed URL and every page switched to noindex changes the tags of all the versions in the cluster.