Microservices architecture is a collection of microservices. A microservice can be defined as follows:

• The smallest service that does only one thing, that is, Single Responsibility Principle (SRP)
• It's an independent piece of code and independently manageable without dangling dependencies
• It's the owner of its own data; no sharing except via services

It is an architectural approach to develop an application (or a system) as a set of small services, where each service works independently in its own process space and communicates using lightweight mechanisms. The services are naturally built around business capabilities just like in SOA, and are independently deployable components as described by bounded contexts in DDD (Domain Driven Design). There is a minimal aspect of centralized management of these services as opposed to traditional SOA architecture