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Host

RequestActive

The Host header is the only mandatory HTTP/1.1 request header. It specifies the domain name and optional port of the server being requested. Without it, servers hosting multiple virtual hosts can't determine which site to serve. HTTP/2 uses the :authority pseudo-header instead.

Host: <host>[:<port>]

Description

The Host request header specifies the host and port number of the server to which the request is being sent. Without a Host header, servers that host multiple sites via virtual hosting would not know which site to return.

Examples

Standard HTTPS
http
Host: www.example.com
Non-standard port
http
Host: api.example.com:8080

Related

400 Bad Request (missing Host)

Specification

RFC 9110 – Host specification →