The rel="alternate" hreflang="x" link attribute is a HTML meta element described in RFC 8288. Hreflang specifies the language and optional geographic restrictions for a document. Hreflang is interpreted by search engines and can be used by webmasters to clarify the lingual and geographical targeting of a website.

Many websites are targeted at audience with different languages and localized for different countries. This can cause a lot of duplicate content or near duplicate content, as well as targeting issues with users from search engines.

Search engines use hreflang to understand the lingual and geographical targeting of websites and use the information to show the right URL in search results, depending on user language and region preference.

There are 3 basic scenarios that can be covered with hreflang:

Hreflang attribute help your website deliver multiple variations of the website in different languages.

Hreflang can be implemented in 3 different ways.

The hreflang definition is done by creating a full set of all language and region specific versions of the same document. Every URL in the set must reference the full URL set. A self-reference is required, so the including document has to be always part of the URL set.

Hreflang accepts values that define languages ISO 639-1 and countries (ISO 3166-1). A language or a combination of language and region can be used as a value. A country-only value is not allowed.