Working with REST
A REST-compliant web service allows a client to interact with the service using a set of predefined stateless operations. REST is not a protocol; it is an architectural style.
Whether or not an interface is truly REST-compliant is not particularly relevant when the goal is to use one in PowerShell. Interfaces must be used according to any documentation that has been published.
Invoke-RestMethod
The Invoke-RestMethod command can execute methods exposed by web services. The name of a method is part of the Uniform Resource Identifier (URI); it is important not to confuse this with the Method parameter. The Method parameter is used to describe the HTTP method. By default, Invoke-RestMethod uses HTTP GET.
Simple requests
The REST API provided by GitHub may be used to list repositories made available by the PowerShell team.
The API entry point, the common URL all REST methods share, is https://api.github.com as documented in the GitHub reference...
