Accept

The Accept request HTTP header advertises which content types, expressed as MIME types, 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 with the Content-Type response header. Browsers set adequate values for this header depending on the context where the request is done: when fetching a CSS stylesheet a different value is set for the request than when fetching an image, video or a script.

Header type Request header
Forbidden header name no
CORS-safelisted request header yes, with the additional restriction that values can't contain a CORS-unsafe request header byte: 0x00-0x1F (except 0x09 (HT)), "():<>?@[\]{}, and 0x7F (DEL).

Syntax

Accept: <MIME_type>/<MIME_subtype>
Accept: <MIME_type>/*
Accept: */*

// Multiple types, weighted with the quality value syntax:
Accept: text/html, application/xhtml+xml, application/xml;q=0.9, image/webp, */*;q=0.8

Directives

<MIME_type>/<MIME_subtype>

A single, precise MIME type, like text/html.

<MIME_type>/*

A MIME type, but without any subtype. image/* will match image/png, image/svg, image/gif and any other image types.

*/*

Any MIME type

;q= (q-factor weighting)

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

Examples

Accept: text/html

Accept: image/*

// General default
Accept: */*

// Default for navigation requests
Accept: text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8

Specifications

Specification
Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content (HTTP/1.1)
# header.accept

Browser compatibility

BCD tables only load in the browser

See also