Trailer

The Trailer response header allows the sender to include additional fields at the end of chunked messages in order to supply metadata that might be dynamically generated while the message body is sent, such as a message integrity check, digital signature, or post-processing status.

The TE request header needs to be set to "trailers" to allow trailer fields.

Header type Response header
Forbidden header name yes

Syntax

Trailer: header-names

Directives

header-names
HTTP header fields which will be present in the trailer part of chunked messages. These header fields are disallowed:

Examples

Chunked transfer encoding using a trailing header

In this example, the Expires header is used at the end of the chunked message and serves as a trailing header.

HTTP/1.1 200 OK
Content-Type: text/plain
Transfer-Encoding: chunked
Trailer: Expires

7\r\n
Mozilla\r\n
9\r\n
Developer\r\n
7\r\n
Network\r\n
0\r\n
Expires: Wed, 21 Oct 2015 07:28:00 GMT\r\n
\r\n

Specifications

Specification Title
RFC 7230, section 4.4: Trailer Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing
RFC 7230, section 4.1.2: Chunked trailer part Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
TrailerChrome Full support YesEdge Full support 12Firefox Full support YesIE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support
Full support

See also