Modu-Liths vs Micro-Services Summarised

Feature	Modular Monolith	Microservices Architecture
Coupling	Loosely coupled at the module level.	Fully decoupled, independent services.
Communication	In-memory function calls.	Network calls (e.g., HTTP, message bus).
Performance	High performance due to in-process communication.	Lower performance due to network latency and serialization overhead.
Database	Shared database, simplifying transactions and reducing complexity.	Each service has its own database, leading to distributed data and more complex transactions.
Deployment	Single deployment unit.	Independent deployment of each service.
Scalability	You have to scale the entire application, even if only one module needs more resources.	Each service can be scaled independently, which is highly cost-effective and efficient.
Operational Overhead	Low; a single application to manage.	High; requires a complex DevOps pipeline to manage many services.
Team Structure	A single team or small number of teams can manage the entire application.	Requires a decentralized team structure, with each team owning one or more services.

Feature	Modular Monolith	Microservices Architecture
Coupling	Loosely coupled at the module level.	Fully decoupled, independent services.
Communication	In-memory function calls.	Network calls (e.g., HTTP, message bus).
Performance	High performance due to in-process communication.	Lower performance due to network latency and serialization overhead.
Database	Shared database, simplifying transactions and reducing complexity.	Each service has its own database, leading to distributed data and more complex transactions.
Deployment	Single deployment unit.	Independent deployment of each service.
Scalability	You have to scale the entire application, even if only one module needs more resources.	Each service can be scaled independently, which is highly cost-effective and efficient.
Operational Overhead	Low; a single application to manage.	High; requires a complex DevOps pipeline to manage many services.
Team Structure	A single team or small number of teams can manage the entire application.	Requires a decentralized team structure, with each team owning one or more services.