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Hreflang Checker

Validate hreflang locale sets for bad codes, duplicate URLs, missing x-default entries, and clean alternate tag output.

Last reviewed: June 11, 2026

About this tool

Check multilingual hreflang sets before release so alternate URLs stay consistent across languages and regions.

Hreflang Checker validates the alternate language and region annotations that tell search engines which version of a page to serve to users in different locales. It verifies correct ISO language and region codes, checks for reciprocal return tags, and flags missing x-default entries that leave international targeting incomplete.

  • Validates locale codes like en, en-US, ko-KR, and x-default.
  • Flags duplicate codes, duplicate URLs, and invalid absolute URLs.
  • Generates cleaned alternate link tags from valid entries.

How to use Hreflang Checker

Paste the hreflang tags from your page head, or provide a URL for the tool to inspect. It cross-checks every language-region pair, confirms that all alternate pages link back to each other, and highlights any orphaned or non-reciprocal annotations that could confuse search engine locale selection.

When this tool is useful

  • Review alternate language and region mappings before launching localized pages.
  • QA hreflang exports from a CMS or spreadsheet before engineering deploys them.
  • Catch duplicate locale rows or missing x-default entries during international SEO audits.

Practical tips

  • Keep alternate URLs absolute and consistent in protocol and host when possible.
  • Use x-default for the fallback experience when you have a global selector or catch-all page.
  • Validate the final live HTML too, because generated tags can still be altered by templates.

Examples you can test

These examples show the kind of real input and reviewed output this tool is designed to support. Use them as a starting point before pasting your own production content, then compare the output with the destination system that will use the result. The goal is not only to produce a value, but to make the input assumptions, output format, and review step clear enough that the result can be trusted in a real workflow.

Audit two language alternates

Example input

en page links to ko page, ko page links back to en page

Expected output

Reciprocal hreflang relationship confirmed

Reciprocal links are required so search systems can trust the alternate-language cluster.

Find a wrong locale code

Example input

hreflang="kr"

Expected output

Warning for invalid or unexpected language-region code

Locale mistakes can prevent the intended page from appearing for regional users.

Validation checklist

Run through these checks before copying the result into a CMS, codebase, spreadsheet, campaign, support ticket, or production document. Small formatting differences, unit assumptions, hidden whitespace, and platform-specific rules are common sources of mistakes in quick browser tools, so the final review should happen in the same context where the output will be used.

  • Check that every alternate URL is absolute, crawlable, and canonical.
  • Verify reciprocal hreflang tags across all language versions.
  • Use valid language and optional region codes such as en, en-US, or ko-KR.

Why people use this tool

Incorrect hreflang implementation causes search engines to show the wrong language version to users, which degrades user experience and wastes crawl budget on pages that will not convert. Because hreflang errors compound across thousands of localized pages, validating the setup before deployment prevents costly rework.

Related search intents

hreflang checker, hreflang validator, check hreflang tags, international SEO tool.

Frequently asked questions

Does this tool support x-default?

Yes. It validates x-default and warns when a fallback entry is missing from the set.

Why does duplicate URL detection matter?

Duplicate target URLs often signal a broken alternate set where multiple locale codes point to the same page unintentionally.

What does it mean when the checker reports a missing x-default entry?

The x-default hreflang value tells search engines which URL to use for users whose language or region does not match any specific hreflang entry. Omitting it can lead to inconsistent international serving.

Does the checker validate that return links exist between all hreflang pairs?

Yes. Bidirectional confirmation is checked, meaning if page A declares page B as an alternate, the tool verifies that page B also references page A, which is a requirement for valid hreflang implementation.

Which locale code format should I use — 'en-US' or 'en_US'?

Hreflang attributes require the BCP 47 format with a hyphen (en-US), not an underscore. The checker flags underscore-separated codes as invalid and suggests the corrected format.

Review and privacy notes

Utiloom reviews tool pages for practical examples, validation checks, browser-side processing notes, and clear limitations before they are promoted in search. Read more about the editorial approach on the About page, check data handling in the Privacy Policy, or contact us if a tool needs correction.

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