Hreflang

Hreflang is an HTML annotation that tells search engines which language and country versions of a page belong together, and which version is intended for which users. It is the backbone of international SEO: without it, Google guesses which version belongs to which market, and the guess is often wrong.

The annotation names a language and optionally a country, such as da-DK for Danish in Denmark and sv-SE for Swedish in Sweden. A typical tag reads:

<link rel="alternate" hreflang="sv-SE" href="https://example.com/" />

It can sit in the page head, in the HTTP header or in the XML sitemap with the same result.

Two requirements trip up most implementations. The annotations have to be reciprocal: if the Danish page points to the Swedish one, the Swedish page has to point back, or Google ignores the pair. And every page also has to reference itself. An x-default catches users with no obvious language match, and only with that in place is the setup complete.

Hreflang is a signal, not a redirect. It does not force anyone onto a version and it does not merge pages. What it does is tell Google that near-identical pages are alternates rather than rivals, so their signals are consolidated instead of competing as duplicate content. Without it, a Danish page can rank in Sweden on the strength of its backlinks alone, and Swedish customers meet prices in Danish kroner. The guide to international SEO runs through the whole discipline.