What architectural patterns have you applied when splitting a monolith?

When splitting a monolith, the following architectural patterns are often used:

• Microservices — dividing the application into independent services with clearly defined boundaries and APIs. Each service is responsible for its own business logic and can develop and scale independently.

• Service-Oriented Architecture (SOA) — similar to microservices but with larger, more integrated services, often using an ESB (Enterprise Service Bus).

• Event-driven architecture — components interact through events, which increases asynchrony and loose coupling.

• API Gateway — a pattern that helps manage interactions between clients and multiple microservices, providing a single entry point.

• Strangler Fig Pattern — gradually replacing parts of the monolith with new services, while the old code is gradually "cut off".

Example: when splitting a large e-commerce monolith, separate microservices can be allocated for managing the product catalog, shopping cart, payment, and users, allowing independent development and scaling of each.