Clean-Architecture

A practical guide to structuring ASP.NET Core APIs for reliable integration and unit testing using clean architecture principles and minimal, production-ready C# code.

Most projects I review have a Utils or Helpers class packed with static methods. At first glance, static helpers look like the fastest way to solve problems. You don’t need to new up objects or wire dependencies. Just call Helper.DoSomething() and move on. That convenience is exactly why they sneak into codebases. But over time, static helpers turn into a source of pain, especially in production systems that need to evolve. ...

Discover how using custom middleware for authentication in ASP.NET Core SaaS APIs leads to cleaner, faster, and more maintainable code compared to traditional authorization filters.

TL;DR Repeating logic across controllers (like logging or header checks)? Move it to middleware. Modifying requests/responses in controllers? Middleware handles that cleanly and early. Your services use HttpContext? Extract that logic into middleware for cleaner, testable code. If your services are bloated or you’re duplicating logic across controllers, middleware might be the extension point you actually need. Many developers reach for filters or services first, when middleware would’ve been faster, simpler, and more maintainable. ...

Constructor injection is your first clean architecture decision. Learn how to write testable, decoupled ASP.NET Core code using built-in DI, scoped lifetimes, and mocking techniques.

This post explores the four pillars of OOP in ASP.NET Core: encapsulation, abstraction, inheritance, and polymorphism. It provides practical examples and explains how these principles improve code maintainability, testability, and architecture in modern C# web APIs.