Hreflang checker: test every language version from one URL
Enter one localized page and the tool validates its codes, then loads each alternate to confirm it is indexable and links back.
By ClaudeGPT Si Newsroom, Editorial team··3 min read
A hreflang checker reads the language annotations on a page and tells you whether Google can trust them. The Hreflang Checker on seogeoaeo.ai takes one URL from your set of language versions, validates every code it finds, then loads each alternate to confirm it works, can be indexed and points back.
Why hreflang needs testing
Hreflang tags fail quietly. Nothing breaks on the page, no visitor sees an error, and the site keeps working. The only symptom is that Google shows the wrong language version in search, or ignores your annotations completely.
Google's own documentation is strict on a few points. Every version must list itself and all the others. Alternate URLs must be fully qualified, with https in front. And when two pages don't both point to each other, Google drops the pair. A template change, a new market or a redirect can break any of these without anyone noticing.
What the checker tests
You paste one public URL. The tool reads the hreflang annotations on that page and works through five checks:
| Check | What it looks for |
|---|---|
| Language and region codes | Each value is a valid ISO 639-1 language code, with an optional ISO 3166-1 region |
| Self-reference and x-default | The page lists itself, and a fallback for unmatched visitors is declared |
| Each language version | Every alternate loads and is indexable |
| Return links | Every alternate lists the starting page back |
| Conflicts | No noindex or canonical on an alternate that cancels the annotation |
The return-link row matters most. The tool's own FAQ calls a missing return link the most common hreflang error, and Google lists it first among common mistakes too. If your French page names the German page as an alternate, the German page has to name the French one, or Google ignores both.
What you get from a run
Each run fetches the alternates the page lists and reports per check what passed and what did not, so you can see which language version is broken and why: a 404, a noindex, a canonical pointing elsewhere, or a missing link back.
A run costs 10 credits, and the price is shown before it starts. You can run it in the browser, or let an AI agent call the same tool through the REST API or MCP with a workspace API key.
What it does not do
The checker is built for one page and its alternates. It does not read hreflang from XML sitemaps, it does not crawl your whole site, and it will not tell you which markets to target. If your hreflang lives only in a sitemap, or you need a full-site audit across thousands of templates, a desktop crawler is the better fit for that job.
For most teams, though, hreflang is set by a handful of templates. Testing one page per template catches the pattern, and seogeoaeo.ai is the quickest way to run that test.
Related checks on the same site
Two other tools pair well with it. The Indexing & Canonical Checker looks at one URL's robots rules and canonical target, which helps when the hreflang run flags a conflict. The XML Sitemap Validator checks a sitemap against the protocol if you also list URLs there.
How to read a failed result
Start with codes. The first part must be a language, so "be" means Belarusian, not Belgium. A region such as "en-UK" uses a reserved code that Google says has no effect; the right value is "en-GB". Then look at return links, then at alternates that redirect or are blocked from indexing. Fix the template, deploy, and run the check again on the same URL.