ASP.NET Core

Learn how to avoid common ASP.NET Core dependency injection lifetime mistakes. This guide covers DbContext misuse, scope leaks in singletons, transient performance traps, background service issues, and middleware lifetime bugs with real production fixes.

Learn why UseRouting() must always come before MapGet() in ASP.NET Core and how the middleware order impacts your request pipeline.

Bad middleware doesn’t just break requests, it breaks entire tenants. Learn the anti-patterns to avoid in your ASP.NET Core SaaS architecture and how to fix them.

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.

In multi-tenant SaaS applications, custom middleware gives you the earliest hook in the request pipeline, even before dependency injection kicks in. Middleware runs at the very beginning of your pipeline, providing access to raw request data before any transformations occur.

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 guide covers how to effectively test ASP.NET Core middleware using unit tests, integration tests, and mocks. It includes examples of common middleware patterns, how to handle dependencies, and best practices for ensuring your middleware behaves correctly in production.

Discover how the Dependency Inversion Principle makes your C# code flexible and testable. Learn to use ASP.NET Core DI to depend on abstractions, swap implementations, and build maintainable, scalable applications with real-world examples.

This guide explains how to add and modify HTTP headers in ASP.NET Core using custom middleware. Covers dynamic header injection, security best practices, CORS configuration, and middleware pipeline ordering for robust API responses.