Do you know the Modular Monolithic architecture?

A Modular Monolith is a software architecture pattern that combines elements of both monolithic and modular architectures. In this approach, the application is built as a single, unified codebase like a traditional monolith, but it is designed and organized in a modular manner, allowing for logical separation of different components or modules within the codebase.

The Modular Monolith architecture is the “goldilocks” approach that combines the modularity of microservices with the simplicity of traditional Monoliths* Steve “Ardalis” Smith

Modular Monolith characteristics

Figure: Modular Monolith architecture

• Single Host/Process
• Single Deployment
• Loosely coupled modules that each have their own
  • Domain
  • Application
  • Infrastructure
  • Presentation (API or UI)
• Each module represents a business capability or domain
• Each module should be as highly cohesive and loosely coupled with other modules
• Each module manages it's own data and persistence

✅ Advantages

• Simplicity in Deployment - Since it's a monolith, the deployment is typically simpler than distributed systems like microservices
• Ease of Development - Developers can work on separate modules without significantly affecting other parts of the application
• Performance - Inter-module communication is often faster and more reliable than inter-service communication in distributed architectures

❌ Challenges

• Scalability - While more scalable than a traditional monolith, it may not scale as effectively as microservices
• Modular Discipline - Maintaining strict modularity can be challenging as the application grows and evolves

A Modular Monolith offers a balance between the simplicity and coherence of a monolith and the modularity and maintainability of more distributed architectures. It is particularly useful for certain kinds of applications and organizational contexts.

Modular Monolith compared to other architectures