Microservices is a recent term used to describe systems where the logic tier of the three-tier pattern is composed of several smaller services that communicate with language-agnostic protocols.

Typically, the language-agnostic protocol is HTTP based, commonly JSON REST, but this is not mandatory. There are several possibilities for the protocol layer.

This architectural design pattern lends itself well to a CD approach since, as we have seen, it's easier to deploy a set of smaller standalone services than a monolith.

Here is an illustration of what a microservices deployment may look like:

We will evolve our example towards the microservices architecture as we go along.