Hreflang Tester

What this tool is used for

• Checking an existing hreflang set for missing reciprocal references.
• Validating language and region codes against the accepted vocabularies.
• Confirming an x-default entry is present and points somewhere sensible.
• Finding duplicate hreflang values that make the set ambiguous.
• Auditing a multilingual template after a change.

Frequently Asked Questions

How are the language and region codes validated?

Against the browser's CLDR registry via Intl.DisplayNames, which returns a name for a known code and echoes the code back for an unknown one. A hand-typed list is the alternative, and in a validator that is a false-error generator: the previous one rejected ga, nb and nn and warned on zh-TW and zh-HK.

What is zh-Hant, and why is it not a region?

A script subtag. A BCP 47 tag runs language, then optional script, then optional region — so zh-Hant is Traditional Chinese with no country attached and zh-Hant-TW names both. A four-letter second subtag is always a script, and reading it as a country invents a warning about a region called HANT.

Can this confirm my whole hreflang setup is correct?

Only the part one page can show. The error Google reports most is a missing return link — every alternate must point back at every other, itself included — which can only be checked by fetching all of them. What is validated here is the tags in front of it: codes, duplicates, absolute URLs, x-default.

Why flag two hreflang values sharing one URL?

Because a URL can be the canonical version of exactly one locale. If en and en-us both point at /en/, there is nothing to distinguish them and the pair is generally ignored. x-default is exempt, since pointing it at the same URL as your default language is ordinary practice rather than a mistake.

Is x-default required?

Recommended rather than required, which is why it produces a warning here and not an error once more than one tag is present. It names the page to serve when no listed locale matches — usually a language selector or the international edition — and without it those visitors get whichever alternate is guessed for them.

Common errors and gotchas

• Treating a valid code as a correct one, since `en-UK` parses as a language but the region code is `GB`.
• Missing the self-reference, which invalidates the set for that page.
• Assuming one-way references work, when the relationship must be reciprocal.
• Overlooking that hreflang is a hint rather than a directive.
• Checking the tags without checking that each target actually returns 200.