What is the difference between Monolithic, SOA and Microservices Architecture?

Monolithic, Service-Oriented Architecture (SOA), and Microservices are three distinct software architecture styles, each with unique characteristics and best-use scenarios.

Monolithic Architecture

In a Monolithic architecture, the entire application is built as a single, unified unit. This means that all components of the application, including the user interface, business logic, and database interactions, are tightly integrated and deployed together as one package[2][5][7]. This architecture is straightforward to develop, test, deploy, and scale horizontally by running multiple copies behind a load balancer. However, it has significant drawbacks, especially in terms of scalability and maintainability. As the application grows, the complexity of managing and updating the codebase can become cumbersome. Moreover, a single bug in any module can potentially bring down the entire system[5].

Service-Oriented Architecture (SOA)

SOA is a more flexible architecture that breaks down an application into multiple discrete services, each performing a specific business function[2][3][4][5][6]. These services communicate with each other over a network, typically using HTTP, allowing them to be developed, deployed, and scaled independently. Each service in an SOA is designed to be reusable, which can lead to significant efficiencies in development and maintenance. However, SOA can introduce complexity in terms of managing service interactions and ensuring performance across distributed services. It often involves an Enterprise Service Bus (ESB) to facilitate service communication, which can become a single point of failure and a bottleneck as the number of services increases[5][6].

Microservices Architecture

Microservices architecture takes the principles of SOA further by decomposing an application into even smaller, more granular services[1][2][3][4][6]. Each microservice is highly specialized and focuses on a single capability o...