Microservices

Microservices are a functional approach well applied to software. It tries to decompose the entire application functionally into a set of services that can be deployed and scaled independently. Each service does only one job and does it well. It has its own database, decides its own schema, and provides access to datasets and services through well-defined application programming interfaces that are better known as APIs, often paired with a user interface. APIs follow a set communication protocols, but services are free to choose their own technology stack and can be deployed on hardware of choice.

In a microservice environment, as shown in the preceding diagram, there are no layers like in monoliths; instead, each service is organized around a bounded context (https://en.wikipedia.org/wiki/Domain-driven_design#Bounded_context) that adds a business capability to the application as a whole. New capabilities in such an application are added as new services that are deployed and scaled independently. Each user request in a microservices-based application may call one or more internal microservice to retrieve data, process it, and generate the required response, as shown in the following diagram. Such software evolves faster and has low technology debt. They do not get married to a particular technology stack and can adopt a new technology faster: