Picto thématique

Rule n° 221 - Headers sent by the server contain information pertaining to the character set used

A web server will serve up loads of information in so-called headers (headers). The character set information must be exposed within the header of a page to ensure reliable rendering.

#SEO #Server and performance #Development


  • Allow the browser to choose the right character encoding to display the page.
  • Improve the way content is taken into account by search engines and indexing tools.


The charset parameter of the HTTP header content-type is completed in the following way: Content-Type: text/html; charset=utf-8 (utf-8 here is an example), depending on the character set actually used by the document and its MIME type.


For each page checked:

  • Check that charset is in the content-type field returned by the server using a dedicated tool;
  • Check that the declared character set actually corresponds to the character set used by the document. If there are incorrect characters instead of accents or the like, best practice will certainly be invalidated.

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