Free hreflang validator

Hreflang is an annotation that tells Google which language and regional version of a page to serve to which users. You declare it as a set of link tags, one per language or region variant, plus an optional x-default for everyone else. It doesn't change rankings on its own — it swaps in the right variant for the right user so a French searcher gets the French page instead of the English one. The variants in a set are supposed to point at each other (return tags).

It fetches the page and reads every hreflang annotation from both sources Google honors: the HTML link rel=alternate hreflang tags and the HTTP Link header. For each one it checks the code is a valid ISO 639-1 language, optionally followed by an ISO 3166-1 region (or x-default), and whether the href is absolute. Across the set it checks that a self-referencing entry is present, that no hreflang value is duplicated or points to conflicting URLs, and whether an x-default exists. It does not crawl each alternate to verify return tags — that is a separate, crawl-level check.

They solve different problems and they can fight each other. Canonical says which URL is the master copy when several are duplicates. Hreflang says which of several genuinely different language or region variants to show. The common mistake is canonicalizing all your language variants to the English page — that tells Google the others are duplicates and should not be indexed, which kills the hreflang set. Each language variant should canonical to itself, then hreflang links the variants together.

It's optional, not required. x-default tells Google which page to serve when none of your listed languages or regions match the user — typically a language selector or your main international page. If you don't set one, Google just picks the closest match it can. For a site that targets a few specific markets it is good practice; for a fully localized site with a sensible fallback it matters less. This tool flags a missing x-default as informational, not an error.

The usual reasons: an invalid code (en-UK instead of en-GB, or a language code that doesn't exist), a missing self-referencing entry, return tags that don't point back (page A links to B but B doesn't link to A), or the variants being canonicalized to a single URL. Google validates the whole set and quietly drops it if the annotations are inconsistent — there is no hard error in Search Console, just the International Targeting report showing no return tags. This tool catches the code and structure problems you can see from a single page.

Not in this free version. Return-tag verification means fetching each alternate URL in the set and confirming it links back to this page with the right hreflang. That is one extra request per alternate, which becomes slow and easy to abuse on an anonymous tool, so it is a crawl-level job rather than a single-page check. This tool validates everything you can see from the page itself: the codes, the self-reference, duplicates, and x-default. If you want continuous reciprocity monitoring across a site, that is what a dedicated international-SEO crawler is for.

Any of the three works, and you should pick one and use it consistently. HTML link tags in the head are the most common and the easiest to inspect. The HTTP Link header is the option for non-HTML files like PDFs. The XML sitemap (xhtml:link) is the most scalable for large sites because it keeps the annotations out of the page. Don't mix methods for the same set — it makes debugging painful and risks conflicting signals. This tool reads the HTML tags and the HTTP header.