**hreflang tags tell engines which version of a page to show users in each language and region — but they only work if they're reciprocal and correct.** This check looks at whether your hreflang annotations map your language/region variants properly and whether the return links are mutual. Broken or one-way hreflang leaves engines guessing, so users land on the wrong-language version.
It checks that your hreflang annotations correctly connect your language and region variants. Specifically:
- Valid codes — hreflang values use correct language and region codes (e.g. en-GB, fr-CA).
- Reciprocity — each language version links to the others and they link back (the return-link requirement).
- x-default — an x-default is provided for users who don't match a specific version.
- Self-reference — each page includes an hreflang entry for itself.
Correct, reciprocal hreflang passes; some issues (missing return links or x-default) is a warning; broken or non-reciprocal hreflang is a fail.
GEObubbly checks the page's hreflang annotations for valid codes and reciprocity. It's an extended International SEO check that runs partially, since verifying reciprocity involves checking the linked versions.
When you have the same page in multiple languages or regional variants, hreflang annotations tell engines which version to show which users — English to English speakers, the Canadian-French version to users in Quebec, and so on. Done right, this ensures people land on the version meant for them and prevents your language variants from being treated as duplicate content competing with each other. But hreflang is notoriously easy to get wrong, and it has a strict rule: reciprocity. If page A says page B is its French version, page B must point back to A — return links must be mutual, or engines ignore the annotation. Each page should also reference itself in the set, use valid language/region codes, and ideally provide an x-default for users who don't match any specific version. Broken, one-way or mis-coded hreflang leaves engines to guess, so users get served the wrong-language page — a poor experience that wastes your localisation effort. The fix is to ensure every variant is mutually linked with correct codes and a self-reference. For GEO, correct hreflang helps AI engines serve and cite the right language version of your content to the right users. It's central to International SEO.
hreflang is an annotation that tells search engines about the different language and regional versions of a page, so they can serve the right version to the right user. For example, it can indicate that one URL is the English version, another the Spanish, and another the French-Canadian, letting engines show users the version matched to their language and location. It also helps prevent your language variants from being seen as duplicate content competing against each other. hreflang can be implemented in the page head, HTTP headers or the sitemap, and it's the standard mechanism for managing multilingual and multi-regional sites.
hreflang requires return links: if page A declares that page B is its alternate language version, page B must declare A as an alternate in return. This reciprocity is how engines confirm the relationship is genuine and agreed by both pages. If the links aren't mutual — A points to B but B doesn't point back — engines treat the annotation as unreliable and may ignore it, so your careful language mapping does nothing. Ensuring every version in a set links to all the others, and they all link back, is essential for hreflang to actually take effect.
x-default is a special hreflang value that specifies the default page to show users who don't match any of your specific language or region versions. For instance, if you have English, German and French versions but a user's language is none of those, the x-default tells engines which version (often a language selector or your primary/international version) to serve as a fallback. It's not strictly required, but including an x-default improves how unmatched users are handled, ensuring there's a sensible default rather than leaving the choice entirely to the engine's guess.
The most common errors are: missing return links (non-reciprocal annotations, which engines ignore); using incorrect language or region codes (wrong or invented codes invalidate the entry); forgetting the self-referencing hreflang on each page; omitting an x-default for unmatched users; and inconsistencies between the hreflang set and canonical tags. hreflang is detailed and unforgiving, so a small mistake can silently break the whole setup. Validating your implementation — checking codes, reciprocity and self-references across all variants — is the way to catch these issues before they send users to the wrong-language pages.
Yes, indirectly. Correct hreflang helps engines understand which language and regional version of your content is meant for which audience, which supports AI engines serving and citing the right version to users in different locales. As AI search operates across many languages and regions, clear signals about your content's language targeting help ensure the appropriate version reaches the appropriate user. hreflang isn't a direct GEO ranking factor, but for international sites it's part of making your localised content correctly understood and matched, which supports accurate representation in AI answers across languages.