Three implementation methods for hreflang — HTML, HTTP headers, or sitemap. Each has a context where it's the

Three implementation methods for hreflang — HTML, HTTP headers, or sitemap. Each has a context where it's the right choice.

HTML head tags: the standard implementation for most sites. Add rel=alternate hreflang tags to the of every page in the cluster. Works for all content types. Requires full HTML access.

HTTP headers: the only option for non-HTML files like PDFs. The server sends hreflang information in the HTTP response headers. Rarely used because most international content is HTML, but essential for document-heavy sites.

XML sitemap: useful when you can't easily modify individual page templates — legacy CMSs, third-party platforms, or situations where adding to hundreds of templates isn't feasible. You add hreflang annotations directly to the sitemap entries.

For most affiliate and content sites: HTML head tags. It's the most reliable, most widely supported, and easiest to audit.

Don't mix methods. If you implement hreflang in both HTML and the sitemap, Google will process both, which can create conflicting signals if they're not perfectly synchronized.