APIs for Modern Commerce

Chapter 3. Implementing APIs

This chapter focuses on actually implementing what’s behind your APIs. You’ve modeled your APIs, but now it’s time to write the code. Here’s how you get started.

Identifying Needs of Clients

Before you start writing code, remember who you’re building APIs for and what they want. Are your APIs primarily for internal developers at your company? Or are they for external developers not employed by your company? Are your APIs for paying customers or for partners?

We’ll discuss this more in Chapter 4, but for now, let’s ask the simple question—who are your clients? Are they other microservices? Are they web frontends? Are they mobile frontends? Your client could be on the other side of the world or on the next rack over in the data center. These are all important considerations. Who’s calling your APIs will have a direct impact on how you design, deploy, and manage them.

Keep these factors in mind as you look at building the code behind your APIs.

Applications Backing APIs

All large applications fall somewhere on a spectrum between monolithic and microservices. A traditional monolithic has multiple business functions in the same codebase. Pricing, orders, inventory, and so on are all included in the same codebase and are deployed as a single large application requiring dozens or hundreds of people working in horizontal (frontend, backend, ops, etc.) teams. These monolithic applications often retroactively add APIs to access functionality contained within ...