What's hreflang and why is it always broken?

Hreflang tells Google which version of a page to serve to users in different countries / languages, e.g. en-GB for UK shoppers, de-DE for German shoppers. Done right, it routes the right user to the right store view and prevents duplicate-content penalties.

It’s almost always broken because of three foot-guns: (1) missing reciprocal tags, if page A links to page B with hreflang, B must link back to A. (2) hreflang loops, A points to B, B points to C, C never points back. (3) wrong locale codes, en_UK instead of en-GB. Magento’s default multi-store setup ships hreflang in the page header but doesn’t validate it. Our audit catches all three on every project.