DevKits

Request negotiation · Request header

Host

The requested host name and port.

What is Host?

Required on all HTTP/1.1 requests. Enables virtual hosting where one IP address serves many domains.

Typical usage

Set automatically by every HTTP client.

Examples

Host: example.com

Also known as

Also commonly written as: host header · http host header · host ヘッダ · ホストヘッダ · virtual host header · host request header. These variants — including plural forms, unhyphenated spellings, and Japanese (ヘッダ) — all refer to the same Host HTTP header.

Specification

RFC 9110 §7.2

Frequently asked questions

What is the Host HTTP header?

Required on all HTTP/1.1 requests. Enables virtual hosting where one IP address serves many domains.

Is Host a request or response header?

Host is a request header — the client sends it to the server. Set automatically by every HTTP client.

What does a Host header look like?

A typical Host header looks like: Host: example.com.

Related headers

Accept

Which media types the client can process.

Accept-Encoding

Which content encodings (compressions) the client accepts.

Accept-Language

Preferred human languages for the response.

User-Agent

The client software identifying itself.

Referer

The URL of the previous page that led to this request.

Work with this header

User-Agent Parser →Parse the User-Agent request header.cURL Converter →Turn a curl command into fetch / code and back.URL Parser →Break a URL into scheme, host, path and query.