Technical SEO

hreflang Cluster

Quick Definition

An hreflang cluster is a set of pages on a site that are language- or region-variants of each other, with reciprocal hreflang annotations linking them as alternates.

In context

hreflang clusters tell search engines which version of a page to serve to which audience: en-CA for English Canadians, fr-CA for French Canadians, en-US for Americans. Implementation rules: every page in a cluster must reference every other (including itself), URLs must be absolute, and all referenced URLs must be canonical and indexable. The most common hreflang bug is asymmetric annotation (page A references B but B doesn't reference A) — Google ignores asymmetric clusters silently. Validate with the Hreflang Tags Testing Tool or Search Console.

Example

Toronto SEO's English and French Quebec landing pages form an hreflang cluster: en-CA/quebec-seo/ and fr-CA/quebec-seo/ each reference the other plus themselves — proper cluster Google honours.

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