Clean Architecture & DDD Mastery
Lesson 15/30

Tutorials Clean Architecture & DDD Mastery

The Infrastructure Layer: Bridging to the outside world

8 min read Updated 6/23/2026
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The Toolset

The Infrastructure Layer contains the actual code that talks to your database, your file system, and external third-party APIs.

1. Implementing Domain Interfaces

This is where the 'magic' of Dependency Inversion happens. If the Domain layer defines IUserRepository, the Infrastructure layer contains the SqlServerUserRepository that uses EF Core's DbContext. The rest of the app doesn't care—it only sees the interface.

2. Third-Party Integration

Need to send an SMS? Use **Twilio**. Need to send an Email? Use **SendGrid**. In Clean Architecture, you create an interface in the Application layer (e.g., IEmailService) and put the Twilio/SendGrid code in the Infrastructure layer. If you want to switch to AWS SES, you only touch this project.

3. Architect Insight

Q: "Should I put my migrations in this project?"

Architect Answer: "YES. Entity Framework Migrations are an 'Infrastructure' detail. By keeping them here, you keep your other projects clean and focused on business logic. The Infrastructure layer is the 'Disposable' part of your app—the part you can swap and change as tech evolves without losing your core investment."

Clean Architecture & DDD Mastery
Course syllabus
1. Architectural Patterns The Evolution of Architecture: Monolith to Clean Onion Architecture: Dependency Inversion at the core Clean Architecture: The 'Screaming' architecture Hexagonal Architecture (Ports and Adapters)
2. Domain-Driven Design (DDD) Foundations Ubiquitous Language: Aligning code with business Entities vs Value Objects: Managing identity and state Aggregates & Aggregate Roots: Defining consistency boundaries Bounded Contexts: Handling complexity in large domains
3. Advanced DDD Patterns Domain Services: When logic doesn't fit in an entity Domain Events: Decoupling side effects via events Repositories: Mediating between domain and data Unit of Work: Ensuring atomic transactions
4. Implementing the Clean Layers The Domain Layer: Zero dependencies, pure C# The Application Layer: Orchestrating use cases The Infrastructure Layer: Bridging to the outside world The Presentation Layer: Decoupling the UI from logic
5. Patterns for Data & Logic CQRS (Command Query Responsibility Segregation) MediatR: Implementing the Mediator pattern in .NET Specification Pattern: Encapsulating business rules Policy Pattern: Handling complex authorization rules
6. Enterprise Domain Challenges Handling Persistence Ignorance with EF Core Mapping Layers: AutoMapper vs Manual Mapping Validation Strategies: FluentValidation in the App Layer Error Handling: Result patterns vs Exceptions
7. Testing Clean Architecture Unit Testing the Domain: Fast and pure Testing Use Cases with Mocks Integration Testing the Infrastructure ArchUnit .NET: Enforcing architectural rules via tests
8. Real-World Case Study Refactoring a 'Spaghetti' Monolith to Clean Architecture DDD in Action: Modeling a complex Logistics system
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