Canonical and Hreflang Tag Helper

One canonical, one alternate per language or region, and an optional x-default.

Canonical URL (the preferred version of this page)

Language and region versions

x-default URL (optional, for users not matched by the above)

Tags

Put these in the head of every version listed, and have each version point back to all the others, including itself. The hreflang value is a language code, optionally with a region, like en or en-us. Confirm each URL returns 200 and is itself canonical.