A background in web requests is valuable before delving into interfaces that run over the top of Hyper-Text Transfer Protocol (HTTP).

PowerShell can use Invoke-WebRequest to send HTTP requests. For example, the following command will return the response to a GET request for the Hey, Scripting Guy blog:

Invoke-WebRequest -UseBasicParsing https://blogs.technet.microsoft.com/heyscriptingguy/