Identify the URL that should receive traffic from users in unspecified locales, typically a language-selector page or your default language homepage
Add a hreflang link element for each language-region variant of the page, plus a separate element with hreflang=x-default pointing to the fallback URL
Ensure every page in the hreflang set references all other pages in the set (including the x-default URL) to form a complete reciprocal annotation cluster
Validate reciprocity by crawling each annotated URL and confirming that each hreflang element in the cluster points back to every other URL in the same cluster
Choose implementation method (HTML link elements, XML sitemap xhtml:link, or HTTP Link header) based on your CMS capability; all three are treated equally by Google
Known gotchas
Missing reciprocal annotations are the most common hreflang error; if page A lists page B as an alternate but page B does not list page A, Google may ignore the entire hreflang cluster for those pages
x-default is not a fallback for unrecognized languages only; it is also the correct annotation for a language-selection splash page that serves all users initially before redirecting, even if you have full language coverage
Mixing implementation methods across a page set (some pages using HTML link elements, others using sitemap annotations) is supported but complicates auditing; standardize on one method per site to reduce maintenance errors
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp