# Content-Language header

Category: [International SEO](https://seo-geo-glossary.com/en/glossary/category/international-seo/) › [hreflang & language tags](https://seo-geo-glossary.com/en/glossary/category/international-seo/hreflang-language-tags/) · Also known as: Content-Language HTTP header

The **Content-Language header** is an HTTP header that states which language group a response is intended for. It describes the intended audience, which is not necessarily the language the text is written in.

## How is the header used?

The value is one or more language tags in BCP 47 format, for example `de`, `en-CA` or `de-DE, en-CA`. RFC 3282 defines the syntax, with several languages separated by commas. According to MDN, content without the header is meant for all language audiences.

The `lang` attribute in HTML serves another purpose. It marks the language of the text and helps browsers with hyphenation and spell checking. The W3C recommends always setting it on the `html` element. The older `<meta http-equiv="content-language">` should no longer be used.

For Google Search the header has no documented role. Google says it detects a page's language with algorithms based on visible content and does not use hreflang or the `lang` attribute for that. Content-Language is not mentioned in its hreflang documentation. Language and country versions are reported with hreflang.

## Example

```http
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Language: de-DE
```

## Not to be confused with

- [HTML lang attribute](https://seo-geo-glossary.com/en/glossary/html-lang-attribute/index.md): states the language of the text and helps browsers with hyphenation and spell checking. It sits in the HTML, not in the HTTP response.
- [hreflang](https://seo-geo-glossary.com/en/glossary/hreflang/index.md): points to other language and country versions of the same page and is the method Google documents for localized versions.

## Related terms

- [Language code (ISO 639-1)](https://seo-geo-glossary.com/en/glossary/language-code/index.md)
- [HTML lang attribute](https://seo-geo-glossary.com/en/glossary/html-lang-attribute/index.md)
- [hreflang](https://seo-geo-glossary.com/en/glossary/hreflang/index.md)
- [HTTP header](https://seo-geo-glossary.com/en/glossary/http-header/index.md)
- [International SEO](https://seo-geo-glossary.com/en/glossary/international-seo/index.md)

## Sources

- [Content-Language – MDN Web Docs](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Content-Language)
- [RFC 3282: Content Language Headers – IETF](https://www.rfc-editor.org/rfc/rfc3282)
- [Declaring language in HTML and HTTP – W3C Internationalization](https://www.w3.org/International/questions/qa-http-and-lang)
- [Tell Google about localized versions of your page – Google Search Central](https://developers.google.com/search/docs/specialty/international/localized-versions)

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Last updated: October 8, 2026
URL: https://seo-geo-glossary.com/en/glossary/content-language-header/