Chapter 1: API Terminology and Types

Learning something new can feel a little like falling over the side of a ship. Everything is moving and you can barely keep your head above water. You are just starting to feel like you understand how something works and then a new piece of knowledge comes out of nowhere and your whole world feels topsy turvy again. Having something solid to hold on to gives you the chance to look around and figure out where you are going. This can make all the difference in the world when learning something new.

In this chapter, I want to give you that piece of land to stand on. As with almost any specialty, API testing and development has its own terminology. There are many terms that have specialized meanings when you are working with APIs. I will be using some of those terms throughout this book and I want to make sure that you and I share a common understanding of what they mean. This will allow me to more clearly communicate the concepts and skills in this book and will give you that piece of solid ground to stand on as you try to learn how to do effective API testing and development. 

As much as possible, I will use standard definitions for these terms, but language is a byproduct of humans and human interactions and so there is some degree of messiness that comes into play. Some terms do not have clearly agreed-on definitions. For those terms, I'll share how I intend to use and talk about them in this book, but be aware that as you read or listen to things on the internet (or even just interact with teammates), you may come across others that use the terms in slightly different ways. Pay attention to how others are using a term and you will be able to communicate well. 

This book is not a dictionary, and so I don't intend to just write down a list of terms and their definitions. That would be boring and probably not all that instructive. Instead, I'll spend a bit of time on the theory of what an API is and how you test it. I will fit in some terminology explanations as we go. 

This chapter will cover the following main topics:

• What is an API?
• Types of API calls
• Installing Postman
• The structure of an API request
• Considerations for API testing
• Different types of APIs

By the end of this chapter, you will be able to use Postman to make API requests and have a good grasp of basic API terminology. You will also have the opportunity to work through an exercise that will help you cement what you are learning so that you can start to use these skills in your day-to-day work.