What is the role of a service in software system architecture and why is it used?

A service in the architecture of software systems is a component that provides a specific set of functions or business logic accessible to other parts of the system or external clients. Its role is to encapsulate and isolate particular tasks, ensuring reusability and simplifying maintenance.

Main reasons for using services:

• Modularity: dividing the system into independent parts.
• Reusability: services can be used in different applications or modules.
• Providing abstraction: hiding complex logic behind a simple interface.
• Scalability: services can be deployed and scaled independently.

For example, in a web application, a service might handle user authentication, providing methods for login, registration, and access rights verification.