Accept

{{HTTPSidebar}} 

The HTTP Accept {{Glossary("request header", "request")}}  and {{Glossary("response header")}}  indicates which content types, expressed as MIME types, the sender is able to understand. In requests, the server uses content negotiation to select one of the proposals and informs the client of the choice with the {{HTTPHeader("Content-Type")}}  response header. In responses, it provides information about which content types the server can understand in messages to the requested resource, so that the content type can be used in subsequent requests to the resource.

Browsers set required values for this header based on the context of the request. For example, a browser uses different values in a request when fetching a CSS stylesheet, image, video, or a script.

* Values can’t contain CORS-unsafe request header bytes, including "():<>?@[\]{},, Delete 0x7F, and control characters 0x00 to 0x19, except for Tab 0x09.

Syntax

Accept: <media-type>/<MIME_subtype>
Accept: <media-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

• <media-type>/<subtype>
  • : A single, precise media type, like text/html.
• <media-type>/*
  • : A media type without a subtype. For example, image/* corresponds to image/png, image/svg, image/gif, and other image types.
• */*
  • : Any media type.
• ;q= (q-factor weighting)
  • : A value in order of preference expressed using a relative {{Glossary("quality values", "quality value")}}  called the weight.

Examples

Using default Accept request headers

HTTP requests made using command line tools such as curl and wget use */* as the default Accept value:

GET / HTTP/1.1
Host: example.com
User-Agent: curl/8.7.1
Accept: */*

Browser navigation typically has the following Accept request header value:

GET /en-US/ HTTP/2
Host: developer.mozilla.org
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
…

After receiving the document, the default Accept values in requests for images on the developer.mozilla.org example look like this:

Accept: image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5

Configuring Accept request headers for JSON responses

Systems that involve API interaction commonly request application/json responses. Here’s an example of a {{HTTPMethod("GET")}}  request where the client specifically requests a JSON response:

GET /users/123 HTTP/1.1
Host: example.com
Authorization: Bearer abcd123
Accept: application/json

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• HTTP content negotiation
• List of default Accept values
• CORS safelist request header restrictions
• A header with the result of the content negotiation: {{HTTPHeader("Content-Type")}} 
• Other similar headers: {{HTTPHeader("TE")}} , {{HTTPHeader("Accept-Encoding")}} , {{HTTPHeader("Accept-Language")}}