Accept-Charset

The Accept-Charset request HTTP header advertises which character set the client is able to understand. Using content negotiation, the server then selects one of the proposals, uses it and informs the client of its choice within the Content-Type response header. Browsers usually don't set this header as the default value for each content type is usually correct and transmitting it would allow easier fingerprinting.

If the server cannot serve any matching character set, it can theoretically send back a 406 (Not Acceptable) error code. But, for a better user experience, this is rarely done and the more common way is to ignore the Accept-Charset header in this case.

Header type	Request header
Forbidden header name	yes

Syntax

Accept-Charset: <charset>

// Multiple types, weighted with the quality value syntax:
Accept-Charset: utf-8, iso-8859-1;q=0.5

Directives

<charset>

A character set like utf-8 or iso-8859-15.

*

Any charset not mentioned elsewhere in the header; '*' being used as a wildcard.

;q= (q-factor weighting)

Any value is placed in an order of preference expressed using a relative quality value called the weight.

Examples

Accept-Charset: iso-8859-1

Accept-Charset: utf-8, iso-8859-1;q=0.5

Accept-Language: utf-8, iso-8859-1;q=0.5, *;q=0.1

Specifications

Specification	Title
RFC 7231, section 5.3.3: Accept-Charset	Hypertext Transfer Protocol (HTTP/1.1): Semantics and Context

Browser compatibility

See also

• HTTP content negotiation
• Header with the result of the content negotiation: Content-Type
• Other similar headers: TE, Accept-Encoding, Accept-Language, Accept