Because Node is designed to make the writing of networked applications easier, those using Node are often building applications composed of many isolated services that are connected via message queues, sockets, REST APIs, and so on. I will describe these as distributed applications composed of isolated services coupled and coordinated through a network into systems that appear integrated to clients. In this section and the sections that follow, we will consider how isolated services can be designed to be memory efficient with a small footprint.

For the purposes of this section and what follows, the word microservice will be used when referring to application architectures composed of many small cooperating services. Generally, we'll explore ideas around how well-designed modularization can often help keep a system from becoming inscrutable by helping maintain expressive, scalable, testable systems that maintain production readiness.

Then, we'll put the microservice...