ASP.NET Core MVC: What Is It?
A lightweight, quick, and adaptable framework for creating web applications based on the Model-View-Controller paradigm is called ASP.NET Core MVC. It is open-source, cross-platform, and a component of the contemporary.NET ecosystem.

What makes it better than the old .NET Framework version?

• Built-in Dependency Injection
• Minimal startup code
• Middleware pipeline instead of Global.asax
• Easy configuration with Program.cs and appsettings.json

Basically, it gives us way more control and performance, while keeping things developer-friendly.

How a Request is Handled — Step by Step
Here’s what happens behind the scenes when someone hits your site.

1. Application Start – Program.cs
The old Startup.cs has merged into Program.cs (starting from .NET 6). This is where your app is bootstrapped.
var builder = WebApplication.CreateBuilder(args);

// Add services to the container
builder.Services.AddControllersWithViews();

var app = builder.Build();

// Configure the HTTP request pipeline
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}"
);

app.Run();

Tip: I like to keep this clean by offloading complex service setups into extension methods.

2. Middleware Pipeline
Think of middleware as a chain of events that the request passes through. You can inspect, modify, or even short-circuit the request before it reaches the controller.

Typical ones include:

• Error handling (UseExceptionHandler)
• Authentication
• Logging
• Static files
• Routing

app.UseRouting(); // enables routing

3. Routing to Controllers
This is where ASP.NET Core figures out which controller and action to call.

For example
URL: /products/details/5
→ controller = ProductsController
→ action = details
→ id = 5

The route pattern in MapControllerRoute makes this work.

4. Controller is Created
The framework uses Dependency Injection to create your controller. If you’ve registered services in Program.cs, they’ll be injected automatically.
public class ProductsController : Controller
{
    private readonly IProductService _service;
    public ProductsController(IProductService service)
    {
        _service = service;
    }

    public IActionResult Details(int id)
    {
        var product = _service.GetProduct(id);
        return View(product);
    }
}

Note. Constructor injection like this helps keep things testable and clean.

5. Action Method is Called
ASP.NET Core figures out the action method to call (like Details) and even binds parameters from the route, query string, or body.
public IActionResult Details(int id)

It just works — no extra parsing needed.

6. Result is Returned
Your action method can return different types of results:

• ViewResult → renders a Razor view
• JsonResult → returns JSON
• RedirectToAction → redirects

return View(product); // returns HTML view

7. View is Rendered
If you return a view, the Razor View Engine kicks in and converts your .cshtml into HTML, which is sent back to the browser.
// Returns Views/Products/Details.cshtml
return View(product);

Done!

Visual Flow of MVC Request in ASP.NET Core
Browser Request
     ↓ 
Kestrel Web Server
     ↓ 
Middleware Pipeline (auth, routing, logging)
     ↓ 
Routing System
     ↓ 
Controller (via DI)
     ↓ 
Action Method
     ↓ 
ActionResult (View, JSON, etc.)
     ↓ 
View Engine (if ViewResult)
     ↓ 
HTML Response to Browser

Key Pieces You Should Know

Best Practices I Follow

• Use [FromRoute], [FromBody], etc. for clarity in parameter binding.
• Keep Program.cs neat — move big configs to separate methods or files.
• Inject services into controllers (not directly calling DbContext or static classes).
• Use filters (e.g., Authorize, ActionFilter) for cross-cutting concerns.
• Return typed ActionResult<T> in APIs for better structure.

Wrapping Up
So that’s how the ASP.NET Core MVC application life cycle works in .NET 6, 7, and 8. Whether you’re building simple web pages or full-blown APIs, understanding how a request moves through your app gives you the power, to optimize, troubleshoot, and architect like a pro.

Hope this guide helps you as much as it’s helped me.