HTTP headers | Trailer (original) (raw)

Last Updated : 12 Jul, 2025

The HTTP Trailer header is a response header that indicates the given set of header fields is present in the trailer of a message encoded with chunked transfer-coding and allows the sender to include additional fields at the end of chunked messages in order to supply metadata.Syntax:

Trailer: header-names

Directives:

• header-names: It is a set of header fields that are present in the trailer of a message encoded with chunked transfer-coding.

Examples:

• In this example, the header that is being used is Max-Forwards which is a request modifier.
  Trailer: Max-Forwards
• In this example the header that is being used is the Host header which is a routing header.
  Trailer: Host
• In this example Trailer header with a large amount of data from a database query, which is a chunked response. The Expires header is used in this example.
  HTTP/1.0 200 OK
  Content-Type: text/plain
  Transfer-Encoding: chunked
  Trailer: Expires
  0\r\n
  Mozilla\r\n
  7\r\n
  Developer\r\n
  9\r\n
  Network\r\n
  0\r\n
  \r\n

Supported Browsers: The browsers compatible with HTTP Trailer header are listed below:

• Google Chrome
• Internet Explorer
• Firefox
• Opera
• Safari