You may be wondering:
How the heck am I supposed to memorize how all these different servers work???
The good news is that you don't need to. When you work with a backend server, it's the responsibility of that server's developers to provide you with instructions, or documentation that explains how to interact with it. For example, the documentation should tell you:

The server has complete control over how the path in a URL is interpreted and used in a request. The same goes for query parameters. While there are a lot of strong conventions around how servers should interpret paths and query parameters, the server can do whatever it wants. That's why you need docs.