What is the difference between monolithic and microservices architecture?

Monolithic architecture is when all components of an application are assembled into a single unit. All logic, interfaces, databases, and business rules are contained within one application.

Microservices architecture breaks down the application into many independent services, each responsible for a specific function or business logic. These services interact with each other via APIs.

Main differences:

• Responsibility separation: in microservices, each part is responsible for its own task, while in monolith — everything is together.
• Scalability: microservices can be scaled independently, monolith — only as a whole.
• Development and deployment: microservices allow different teams to work in parallel and update parts without stopping the entire application.
• Complexity: microservices require management of network, communication, and consistency, while monoliths are simpler in this regard.

Example: an online store in monolith — one large project, in microservices — separate services for catalog, cart, payment, etc.