Difference between SOA architecture and microservices

Service Orientation architecture is a software architectural pattern where application components provide services to another component via a communication protocol over a network whereas Microservices is a software architecture pattern in which complex application is composed of small independent components and they communicate with each other through a language agnostic api's.

In Service Orientation architecture, there are majorly two roles one is consumers and others are providers. The consumer layer is a point where consumers like us or other services, third parties etc interact with SOA  whereas providers consist of all the services defined within the architecture.

Enterprise Service Bus is a common gateway that allows a communication between consumers and providers. It allows the point to point communication between the modules. 

Microservice is independently deployable or able to shut down a service which is not required. Microservice is a collection of services which are independent of each other. As explained in below figure each service is independent and can able to transfer the information easily independently as every service has its own database.

The main difference lies between SOA  and Microservice is that if suppose there will be an error in Enterprise Service Bus then whole system will be at fault, whereas in microservice architecture each and every service is handled independently so, if  in case there will be an issue in one service then only that service will be effected others will not. In SOA services shares the data storage whereas in microservice each service has its own database i.e. data storage. It allows simple and tight coupling. It is easier in microservice to deploy any new functionality as the code is modular in structure and no dependency of data is there.

So to summarize in last, microservice architecture is simpler and easy to maintain with less complexity which allows us to maintain the code structure independently and also helps in maintaining the size and scope of the project.