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).


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


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


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


Specification Title
RFC 7231, section 5.3.2: Accept Hypertext Transfer Protocol (HTTP/1.1): Semantics and Context

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
AcceptChrome Full support YesEdge Full support 12Firefox Full support Yes
Full support Yes
Notes In Firefox 66, the default Accept header value changed to */*.
IE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support Yes
Full support Yes
Notes In Firefox 66, the default Accept header value changed to */*.
Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes


Full support
Full support
See implementation notes.
See implementation notes.

See also