Making a call to the operation exposed from the service can be done using any tool or library that can execute the HTTP requests. The first obvious choice would be just a web browser. But a web browser is convenient only for executing GET requests (as for getting a list of books from our bookstore service). If you need to execute other methods such as POST or PUT or provide additional request parameters, header values, and so on, you will need to use some alternatives. The first choice could be cURL, a command-line tool for transferring data using various protocols. Let's look at other options we have.