What is a Modular Monolith?
A Modular Monolith is a software architecture style where a single deployable unit is organized into well-defined, loosely coupled modules. Each module encapsulates a specific business capability with its own data, logic, and API surface.
Unlike a traditional monolith, the boundaries between modules are explicit and enforced. Unlike microservices, you get the simplicity of a single deployment, a single database connection, and no distributed system complexity.
The Modular Monolith gives you the best of both worlds - strong modularity with operational simplicity.
Want to master this architecture? My Modular Monolith Architecture course covers the complete approach I use for building production systems.
Getting Started
These articles introduce the core concepts and help you understand when a Modular Monolith is the right choice for your project.
- What Is a Modular Monolith?
- Monolith to Microservices: How a Modular Monolith Helps
- Scaling Monoliths: A Practical Guide for Growing Systems
Module Boundaries and Data Isolation
Getting module boundaries right is the most important design decision. These articles cover how to define boundaries, isolate data, and enforce separation.
- Modular Monolith Data Isolation
- How to Keep Your Data Boundaries Intact in a Modular Monolith
- Internal vs Public APIs in Modular Monoliths
- Refactoring Overgrown Bounded Contexts in Modular Monoliths
Communication Patterns
Modules need to communicate without creating tight coupling. These articles cover synchronous and asynchronous patterns for inter-module communication.
- Modular Monolith Communication Patterns
- Orchestration vs Choreography
- How to Use Domain Events to Build Loosely Coupled Systems
- Building a Custom Domain Events Dispatcher in .NET
Testing
Testing a Modular Monolith requires strategies that validate both individual modules and cross-module interactions.
- Testing Modular Monoliths: System Integration Testing
- Enforcing Software Architecture with Architecture Tests
- 5 Architecture Tests You Should Add to Your .NET Projects
Migrating to Microservices
A Modular Monolith is often the best starting point before moving to microservices. These articles cover when and how to make that transition.
- Breaking It Down: How to Migrate Your Modular Monolith to Microservices
- Understanding Microservices: Core Concepts and Benefits
Vertical Slices in a Modular Monolith
Vertical Slice Architecture is a natural fit inside individual modules. These articles explore how the two approaches complement each other.
