TECHNICAL · SEO GLOSSARY
Hreflang
An HTML link attribute (`rel="alternate" hreflang="en-gb"`) that tells Google which language/region version of a page to serve to users in each locale — the foundation of international SEO for multilingual or multi-region sites.
Definition
Hreflang is an HTML link element attribute that signals to Google (and Yandex) the relationship between language or region variants of the same content. The implementation: in the `<head>` of each page, add a set of `<link rel="alternate" hreflang="[locale]" href="[URL]">` tags pointing to all variants including the current page (self-referencing). For example, a UK English page would include: `hreflang="en-gb"` pointing to the UK URL, `hreflang="en-us"` pointing to the US URL, `hreflang="fr"` pointing to the French URL, and `hreflang="x-default"` pointing to the fallback URL for unmatched locales. The locale values follow IETF BCP 47 language tags: `en` (English), `en-gb` (British English), `fr-fr` (French in France), `zh-hans` (Simplified Chinese).
Why it matters for SEO
Without hreflang, Google may serve the wrong language version to users — ranking the US English page for UK English searches, or serving the English page to French-speaking users. It also prevents the different language versions from being treated as duplicate content competing with each other, since hreflang explicitly tells Google they are equivalents targeting different audiences. Common implementation mistakes: missing the self-referencing tag on each page (every page must reference itself and all its variants); inconsistent hreflang values between the canonical and alternate pages (if the US page references the UK page, the UK page must reference the US page back — the relationship must be bidirectional); including URLs that return non-200 status codes; and using incorrect locale codes (`en-UK` instead of `en-gb`).
How DeepSEOAnalysis checks this
The audit checks for hreflang implementation on crawled pages: validates that hreflang tags are present on pages with multiple language variants, checks for bidirectional consistency (each referenced alternate page must reciprocate the reference), validates locale code format (BCP 47), checks that all hreflang URLs return 200 status codes, and verifies `x-default` presence. For sites with a single language and no international targeting, the absence of hreflang is expected and not flagged.
Useful tools and resources
GLOSSARY
Related terms
technical
International SEO
Optimising a website to rank in multiple countries and/or languages — using hreflang tags, ccTLDs or subdirectories, and geotargeted content to signal which version serves which audience.
Read definition →technical
Canonical URL
The preferred URL for a page, declared via <link rel="canonical"> to prevent duplicate content from splitting ranking signals.
Read definition →technical
Geo-Targeting
Configuring a website to serve different content, or to signal relevance, to users in specific geographic locations — via country-code TLDs, hreflang tags, server location, or Search Console property settings.
Read definition →onpage
Duplicate Content
Identical or substantially similar content appearing at multiple URLs — which forces Google to choose one version to index and can dilute ranking signals across copies.
Read definition →See how your site scores on Hreflang.
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