Via

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 Via request and response header is added by proxies, both forward and reverse. It is used for tracking message forwards, avoiding request loops, and identifying the protocol capabilities of senders along the request/response chain.

Header type Request header, Response header
Forbidden header name Yes

Syntax

http
Via: [<protocol-name>/]<protocol-version> <host>[:<port>]
Via: [<protocol-name>/]<protocol-version> <pseudonym>

Directives

<protocol-name> Optional

The name of the protocol used, such as "HTTP".

<protocol-version>

The version of the protocol used, such as "1.1".

<host>

Public proxy URL and optional <port>. If a host is not provided, then a <pseudonym> must be used.

<pseudonym>

Name/alias of an internal proxy. If a pseudonym is not provided, then a <host> must be used.

Examples

http
Via: 1.1 vegur
Via: HTTP/1.1 GWA
Via: 1.0 fred, 1.1 p.example.net

Specifications

Specification
HTTP Semantics
# field.via

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Via

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also