JavaScript Everywhere

Chapter 2. API Introduction

Picture yourself seated in a booth at a small, local restaurant where you’ve decided to order a sandwich. The server writes your order on a slip of paper and passes that paper to the cook. The cook reads the order, takes individual ingredients to build the sandwich, and passes the sandwich to the server. The server then brings the sandwich to you to eat. If you would then like some dessert, the process repeats.

An application programming interface (API) is a set of specifications that allows one computer program to interact with another. A web API works in much the same way as ordering a sandwich. A client requests some data, that data travels to a web server application over the HyperText Transfer Protocol (HTTP), the web server application takes the requests and processes the data, and the data is then sent to the client over HTTP.

In this chapter we’ll explore the broad topic of web APIs and get started with our development by cloning the starter API project to our local machine. Before we do that, however, let’s explore the requirements of the application that we’ll be building.

What We’re Building

Throughout the book we’ll be building a social note application called Notedly. Users will be able to create an account, write notes in plain text or Markdown, edit their notes, view a feed of other users’ notes, and “favorite” the notes of other users. In this portion of the book, we’ll be developing the API to support this application.

In our API: ...