| 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. |