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.

Set automatically by every HTTP client.

Host: example.com

RFC 9110 §7.2

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.