Hreflang Cluster Checker
Find missing connections between your language versions.
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Google’s hreflang documentation ↗About Hreflang Cluster Checker
Paste one alternate-language annotation per CSV row. The checker compares the relationships you provide, flags missing self-references and return links, and catches conflicting targets for the same language. It does not crawl URLs or verify indexing, canonical tags, language content or full ISO code membership.
Frequently Asked Questions
Use source,hreflang,target headers. Source is the page containing the annotation; target is its alternate URL. Include self-references as separate rows. Use complete HTTP(S) URLs. Limits: 1 MiB, 2,000 rows and 2,048 characters per URL.
Google recommends consistent sets, but can process partial sets with bidirectional links. This checker does not assume that every page on a website belongs to one complete cluster. A target missing from your CSV is unverified, rather than proof of a live-site error.
This tool checks common syntax: a two-letter language, optional four-letter script, optional two-letter region, or x-default. It flags UK, EU and UN region mistakes. Passing syntax does not verify that a code exists or is supported by Google; confirm codes in the documentation.