Program.cs and Main Entry Point — Complete Guide

Program.cs and Main Entry Point — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ASP.NET Core MVC Tutorial on Toolliyo Academy.

8 min read Updated 6/26/2026

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ASP.NET Core MVC Tutorial · Lesson 18 of 200

Program.cs and Main Entry Point

Getting Started ✓ → Core MVC → Data & Security → Production → Career

Beginner · 2 — Project Structure · ~6 min · Section 2: ASP.NET Core Basics & Hosting

What is this?

Program.cs is the front door of your ASP.NET Core app — it registers services (DI), builds the HTTP pipeline (middleware), and starts the web server.

Why should you care?

Every feature — EF Core, Identity, MVC — gets wired here. When something is not registered, you will debug Program.cs first.

See it live — copy this example

Create an MVC project (dotnet new mvc), add the code, and run dotnet run.

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddControllersWithViews();

var app = builder.Build();
app.UseStaticFiles();
app.UseRouting();
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");
app.Run();

Run Example »

Edit the code and click Run — like W3Schools Try it Yourself.

Code

Result

What happened?

CreateBuilder loads appsettings.json.
AddControllersWithViews registers MVC.
Middleware order matters: static files, routing, then endpoints.

Try it yourself

Open Program.cs in ShopNest.
Add a comment above each line explaining its job.
Temporarily comment UseStaticFiles — refresh and see CSS disappear.
Change text or labels in the example and run again — watch the browser update.
Break the code on purpose (remove a semicolon), read the error message, then fix it.

Remember

Program.cs = configure services + middleware pipeline. AddControllersWithViews enables MVC. Order of Use* calls is critical.

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