The Power BI API is a way of essentially bypassing the web interface of powerbi.com and asking questions directly to the back-end of the service (without bypassing security). Using this allows you to issue a command, such as “Give me a list of all of the workspaces” and receive just the result data in a bulk data format. While outside the scope of this exercise, the API also allows reading actual business data from Power BI assets and even manipulating assets.
For my first attempt at interacting with the API, I decided to try the Microsoft developed Powershell Cmdlets. These are a set of free Powershell commands which can be installed on your workstation and then will query the Power BI API and return results in a standard way without the need to write any code (C# or otherwise) or understand how to read a JSON response.
Jeff does more than just hit API endpoints, though, so read the whole thing.