Content-Length

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The HTTP Content-Length header indicates the size, in bytes, of the message body sent to the recipient.

Header typeRequest header, Response header, Content header
Forbidden request headerYes
CORS-safelisted response headerYes

Syntax

http
Content-Length: <length>

Directives

<length>

The length in octets.

Specifications

Specification
HTTP Semantics
# field.content-length

Browser compatibility

See also