How can I see what opportunities the APIs of different websites have? Do I have to read an explanation or is it possible to get possible commands from the API itself?
There are a few ways to get to know an API ... and it depends on the context. 1. If the API has definition file ( like XML APIs which have WSDL files ). 2. If the website itself refers to a documentation on how to use it's API. 3. Use the DevTools Console to figure out what requests you do with different actions on the site / app, look at the request headers to find how and if they do authentication ( most of them do nowadays ) It's hard to figure out what you want without a more specific context.