What are hreflang tags?

Hreflang tags are HTML link elements that tell search engines which language and regional version of a page to show to users in different countries.

Do I need hreflang tags?

Only if your site has content in multiple languages or targets different regions with the same language (e.g., English for US vs UK). Single-language sites do not need them.

The x-default hreflang value tells search engines which page to show when no other language version matches the user's preferences. It acts as a fallback.

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How to Fix Hreflang Tag Issues

SEO Feb 27, 2026 2 min read

What the hreflang check tests

SiteCurl scans for <link rel="alternate" hreflang="..."> tags in the page head. If hreflang tags are present, it validates the language codes against the ISO 639-1 standard and checks whether an x-default fallback is included when multiple languages are defined.

If no hreflang tags exist, the check passes, since single-language sites do not need them.

Why it matters

Incorrect hreflang tags cause search engines to show the wrong language version of your page. A French user might see the German version, or an English speaker might land on the Spanish page. Invalid language codes are silently ignored, so the tags have no effect at all.

How to fix it

Use valid ISO 639-1 language codes

Language codes must be two-letter ISO 639-1 codes. Optionally add a region with a hyphen:

<link rel="alternate" hreflang="en" href="https://example.com/">
<link rel="alternate" hreflang="fr" href="https://example.com/fr/">
<link rel="alternate" hreflang="en-gb" href="https://example.com/uk/">

Common mistakes: using en-us (valid) vs eng (invalid three-letter code), or zh-hans (valid) vs chinese (invalid).

Add an x-default tag

When you have multiple language versions, include an x-default fallback:

<link rel="alternate" hreflang="x-default" href="https://example.com/">

This tells search engines which page to show when no language version matches the user.

Ensure bidirectional references

Every page must reference all other language versions AND itself. If your English page links to the French version, the French version must link back to the English one.

How to verify the fix

View the page source and search for hreflang. Confirm each tag has a valid ISO 639-1 code and that x-default is present. Run a SiteCurl scan to check the hreflang finding in the SEO section.

Hreflang tags work alongside your canonical URLs and title tags. Each language version should have its own unique canonical URL and unique title in the appropriate language.

Start a free trial to validate your hreflang implementation.