CQRS and MediatR in .NET Projects

Build modern, maintainable, and testable .NET applications by mastering CQRS (Command and Query Responsibility Segregation) with the MediatR library. CQRS and MediatR in .NET Projects is a hands-on, in-depth guide designed for .NET developers who want to structure their applications for better scalability, flexibility, and separation of concerns using proven architectural principles.
CQRS is a powerful pattern that helps developers decouple the responsibilities of reading and writing data within an application. Combined with the popular MediatR library, it promotes clean code, enforces single responsibility principles, and removes unnecessary dependencies between components. This book will show you how to implement CQRS in real-world .NET applications—step by step—with a strong emphasis on clean architecture, best practices, and scalable software design.
From understanding the core concepts of CQRS to building full-featured .NET applications using commands, queries, MediatR pipelines, and dependency injection, this book walks you through every layer of implementation. You'll learn how to keep your controllers lean, encapsulate business logic in handlers, and ensure high test coverage with easy-to-mock classes and interfaces.
Key topics covered:

• The fundamentals of CQRS and the motivation behind separating read and write operations
• How MediatR simplifies the interaction between controllers and application logic
• Building and organizing clean architecture projects that naturally support CQRS
• Creating Command and Query handlers, integrating validation, and writing testable components
• Implementing MediatR pipeline behaviors for cross-cutting concerns like logging, validation, and caching
• Integrating CQRS with Entity Framework Core for optimal performance and consistency
• Using CQRS in ASP.NET Core Web APIs with dependency injection and controller refactoring
• Writing comprehensive unit and integration tests for commands, queries, and pipelines
• Handling advanced use cases like domain events, event-driven architecture, and microservices

This book is packed with practical examples, best practices, and real-world guidance you can apply immediately to new or existing .NET projects. You'll explore advanced topics like custom pipeline behaviors, query projection, repository patterns, and how to keep your application architecture clean and modular.
Who is this book for?

• .NET developers building complex or enterprise-grade applications
• Backend engineers who want to improve application structure and maintainability
• Architects and tech leads implementing clean architecture or microservices
• Developers learning MediatR and seeking real-world examples beyond basic tutorials
• Professionals preparing for technical interviews and needing architectural knowledge

With CQRS and MediatR, you can transform your .NET projects into scalable, testable, and maintainable systems that are easy to extend and refactor. This book provides not only the technical skills to implement the pattern but also the reasoning behind every architectural decision.
If you’re looking to master CQRS with MediatR and elevate your application architecture, this is the comprehensive guide you’ve been searching for.