Feature-based modularity and microservices are concepts at different architectural levels. They are not
direct alternatives.
Feature-Based Modularity
In this approach, one application is divided into modules based on business features:
app
├── feature-history
├── feature-conversation
├── feature-contact
├── feature-profile
└── core
For example, in the Talk project:
feature-history
├── data
├── domain
└── presentation
Characteristics:
• Modules are usually located in the same repository.
• They are usually built and deployed together.
• They communicate through function calls, interfaces, or dependency injection.
• They may share the same database.
• The main goals are better code organization, lower coupling, clearer ownership, and faster builds.
In backend systems, this structure is often called a modular monolith.
Microservices
In a microservices architecture, each business capability is a separate application or service:
User Service
Message Service
File Service
Notification Service
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Each service usually:
• Runs as an independent process.
• Can be built and deployed independently.
• May have its own repository.
• Usually owns its own database or data.
• Communicates with other services through HTTP, gRPC, or a message broker.
• Can scale and fail independently.
Main Difference
Feature-based modularity separates the source code inside one application.
Microservices separate the runtime system into independently deployable applications.
Feature module:
History → direct interface or function call → Transfer module
Microservices:
Message Service → HTTP, gRPC, or event → File Service
Comparison
Aspect
Feature-Based Modularity
Microservices
Deployment
Usually together
Independently
Runtime
Usually one process
Multiple processes
Communication
Direct calls and interfaces
Network calls or events
Database
Can be shared
Preferably owned per service
Complexity
Moderate
High
Failure handling
Simpler
Requires distributed-system handling
Best suited for
Mobile apps and modular monoliths
Large backend systems
Can They Be Used Together?
Yes.
A microservice can internally use feature-based modularity:
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Message Service
├── feature-send-message
├── feature-history
├── feature-reaction
└── core
So microservices define the boundaries between independently deployed systems, while feature-based
modularity defines the internal structure of each application or service.
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