--- title: "Hreflang checker and validator, on every publish | Fimo" url: "https://fimo.ai/agents/hreflang" description: "The SEO agent in Fimo validates hreflang tags on every publish: return links, language codes and x-default, each error fixed in a preview you approve." --- [Agents](/features/agents) [SEO](/agents/seo) Hreflang # Hreflang tags, _checked on every publish_. One missing link and Google shows the wrong language. Your [SEO agent](/agents/seo) validates your hreflang tags every time you publish and fixes the errors. --- ## What is hreflang? Hreflang is a tag that connects [the language and country versions of the same page](/features/visual-editor), like /pricing in English and /fr/pricing in French, so [Google shows each searcher the right one](/features/seo-geo). The tags only work when every version points to every other version, itself included, with valid language and region codes. Google ignores the ones that do not. acme.com | Issue | Pages | | --- | --- | | Missing return linksFix ready | 18 | | en-UK instead of en-GBFix ready | 4 | | Valid | 114 | --- ## Why hreflang breaks so easily. Every new page, every new translation and every URL change has to be reflected in every language version at once. Miss one return link and Google ignores the whole set: visitors see the wrong language, and your versions compete with each other instead of each ranking in its own market. Hreflang is the foundation of international SEO, and on a multilingual site that publishes every week, nobody checks it by hand for long. - 67% of sites using hreflang have at least one hreflang error. - 16.9% have hreflang tags pointing to redirected or broken pages. - 15.3% have pages missing the return link Google requires. [Source: Ahrefs, study of 374,756 domains using hreflang (2023)](https://ahrefs.com/blog/hreflang-study/) --- ## How it works. On every publish, four steps. You only do the last one. 1. ### Lists every version The SEO agent maps each page to its versions in every language and country your site serves, including the ones just published. 2. ### Validates every tag Return links in both directions, language and region codes, the x-default fallback, and whether each tag points to a live page. 3. ### Prepares the fix A missing return link added, an invalid code corrected, a tag pointing to an old address updated to the new one. 4. ### You approve, or it publishes The fixes wait in a preview with a short report: publish them, edit them, or turn them down. Or switch the routine to automatic and the SEO agent publishes them itself. Every version of the site is kept. --- ## Before and after. One product page in three languages, and what changes once the SEO agent fixes its tags. The fixes are highlighted. /jackets/waxed in English, French and German - **Return link: does the French page point back?**: Before:No, so Google ignores the whole set of tags - After: Yes, every version points to every other - **Region code: the British version**: Before:“en-UK”, a code Google does not recognise - After:“en-GB”, the valid code - **x-default: visitors from other countries**: Before:No fallback, so Google picks a version on its own - After: Sent to the English page by default --- ## What you get. - ### The right language in every market Searchers in each country see the version written for them in the search results, with the right language, prices and details: a better user experience from the first click. - ### No ignored tags Every set of tags is complete and valid, so Google actually uses them instead of silently dropping them. - ### Translations that rank Each language version ranks in its own market, instead of competing with the others for the same searches. --- ## The most common hreflang errors. What a hreflang validator looks for, and what the SEO agent fixes on every publish. - ### Missing return links Each version must point to every other version, and back. Google states it plainly: if two pages do not both point to each other, the tags will be ignored. - ### Invalid language or region codes Google only supports language codes in ISO 639-1 format and country codes in ISO 3166-1 Alpha 2 format. “en-GB” works; “en-UK”, a very common mistake, does not. - ### No x-default The x-default value tells Google which page to show when no language or region matches the visitor. Without it, Google chooses on its own. - ### Tags pointing to dead pages A version that was renamed, redirected or deleted, while the other languages still point to its old address. --- ## Works with your tools. The SEO agent checks your tags itself. Search Console shows how each version performs, Semrush or Ahrefs add their audits. - ![](https://increasing-magenta-albatross-5c363716c5.fimo.site/uploads/2026/10/14/RjAOwoMo-search.google.com.png) Search Console - ![](https://increasing-magenta-albatross-5c363716c5.fimo.site/uploads/2026/10/14/QMzXTo9x-semrush.com.png) SEMrush - ![](https://increasing-magenta-albatross-5c363716c5.fimo.site/uploads/2026/10/14/vg6ALI2--ahrefs.com.png) Ahrefs --- ## Works well with. The routines that pick up where Hreflang stops. - [ ### Translation Every page and label, in each of your languages. ](/agents/translation) - [ ### Technical SEO Indexing, sitemap, redirects, headings. ](/agents/technical-seo) - [ ### Broken links Internal and outbound links, found and repaired. ](/agents/broken-links) --- ## Questions about hreflang. Straight answers. ### Is the SEO agent a hreflang checker? Yes, one that runs on every publish. A hreflang tag checker usually tests one URL at a time, when you think of it. The SEO agent checks every page in every language each time the site changes, and prepares the fix for each error instead of handing you a list. ### What does a hreflang validator check? That every version links to every other version and to itself, that each tag uses a valid language and region code, that an x-default is set, and that every address in the tags points to a live page rather than a redirect or an error. The SEO agent runs all of these checks on every publish. ### What are the most common hreflang errors? According to Ahrefs’ study of 374,756 domains, 67% of sites using hreflang have at least one error. The most frequent are a missing x-default, missing self-references, tags pointing to redirected or broken pages, and missing return links, which Google treats as a reason to ignore the tags altogether. [Source: Ahrefs, study of 374,756 domains using hreflang (2023)](https://ahrefs.com/blog/hreflang-study/) [Source: Google Search Central, “Tell Google about localized versions of your page”](https://developers.google.com/search/docs/specialty/international/localized-versions) ### Do I need an x-default tag? It is not required, but it is recommended. Google uses x-default when no other language or region matches the visitor’s settings, so it decides where visitors from every other country land. Most sites point it to their main language or to a language selector. [Source: Google Search Central, “Tell Google about localized versions of your page”](https://developers.google.com/search/docs/specialty/international/localized-versions) ### Should hreflang go in the HTML, the HTTP headers or the sitemap? Any of the three: hreflang attributes in the HTML head, HTTP headers, or entries in your XML sitemap. Google says the methods are equivalent, so the best hreflang implementation is the one your site can keep consistent. What matters is using one method throughout, without contradictions. The SEO agent keeps the method your site already uses. [Source: Google Search Central, “Tell Google about localized versions of your page”](https://developers.google.com/search/docs/specialty/international/localized-versions) ### Does hreflang tell Google what language a page is in? No. Google says it does not use hreflang or the HTML lang attribute to detect a page’s language: it reads the content itself. Hreflang tells Google which version to show to which searcher, once it knows the versions exist. [Source: Google Search Central, “Tell Google about localized versions of your page”](https://developers.google.com/search/docs/specialty/international/localized-versions) ### Can I generate hreflang tags for free? Yes. For a one-off set of tags, use our free [hreflang generator](/tools/hreflang-generator): list each language version of a page and it writes valid tags for HTML, sitemaps or HTTP headers. The SEO agent is for keeping them valid as the site changes. ### How is this different from translation? [Translation](/agents/translation) writes each page in your other languages. Hreflang connects those versions so Google shows the right one in each market. The two work together: every new translation needs its tags, and the SEO agent adds them when it is published. ### Which plan includes it? Every plan, Free included: the SEO and GEO agents run on all plans. Paid plans add more AI credits and agent-hours. See the pricing page for the details. --- ## Where to next. [ ### Agent library Every ready-made agent and what it runs on its own, from SEO and GEO to content and compliance. Add yours in plain words. ](/features/agents)[ ### Website Autopilot Agents and your team, side by side. Agents improve the site on their own, and every version is kept, so you can always go back. ](/features/autonomous-agents) --- ## Start with your website. Try Fimo online in seconds. Connect your site when you are ready. [Try Fimo for free](/auth/sign-up) Book a demo