What does an HTTP request consist of? What headers do you know, and how have you used them?

An HTTP request consists of several parts:

1. Request line — contains the method (GET, POST, PUT, etc.), URL, and protocol version.
2. Headers — key-value pairs that convey meta-information about the request.
3. Body — an optional part used to transmit data, for example, in POST.

Examples of headers:

• Content-Type: indicates the type of data being transmitted, e.g., application/json.
• Authorization: contains a token or data for authentication.
• Accept: indicates which response formats the client is willing to accept.
• User-Agent: information about the client.

In practice, headers are used to configure requests, for example, adding Authorization for access to protected APIs, or using Content-Type for correct transmission of JSON in the request body.