In today’s fast-paced development environment, building scalable and maintainable APIs is essential. ASP.NET Core has emerged as a powerful framework for creating modern web APIs, and when combined with Clean Architecture principles, MediatR for CQRS, Entity Framework Core, and Cosmos DB, it becomes a robust foundation for real-world applications.
In this guide, we’ll walk through the process of building a clean and well-structured CRUD API for a simple Todo app using .NET 8, MediatR, EF Core with Cosmos DB, and NSwag for automatic Swagger documentation. Whether you're creating enterprise-grade microservices or looking to enforce separation of concerns in your architecture, this article will help you set up a production-ready foundation with best practices.
We'll cover:
Setting up a Clean Architecture solution with separate layers (Domain, Application, Infrastructure, API)
Using CQRS with MediatR to handle Create, Read, Update, and Delete operations
Connecting to Azure Cosmos DB using Entity Framework Core
Exposing a fully-documented REST API using NSwag (Swagger UI)
Let’s dive in and build a clean, scalable .NET API from scratch.