Tutorials ASP.NET Core Web API Tutorial

ASP.NET Core Web API Main Method — Complete Guide

ASP.NET Core Web API Main Method — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ASP.NET Core Web API Tutorial on Toolliyo Academy.

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ASP.NET Core Web API Tutorial · Lesson 17 of 175

ASP.NET Core Web API Main Method

BeginnerIntermediateAdvancedProfessional

Beginner · 1 — Setup & foundations · ~6 min · Module 2: Web API Basics

What is this?

ASP.NET Core Web API Main Method is core Web API knowledge for ShopNest.API — how projects start, how HTTP maps to C# controllers and services.

Why should you care?

Interviewers expect you to explain Program.cs, controllers, DI, and Swagger on a whiteboard.

See it live — copy this example

Create a Web API (dotnet new webapi), paste the example, run dotnet run, test in Swagger.

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    [HttpGet]
    public IActionResult Get() => Ok(new[] { "ShopNest" });
}

Run Example »

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

Code
Result

What happened?

  • Study the example, run dotnet run, and test in Swagger.
  • ASP.NET Core Web API Main Method connects to earlier modules in this course.

Try it yourself

  1. Read what ASP.NET Core Web API Main Method means for ShopNest.API.
  2. Type the example — do not only copy-paste.
  3. Test in Swagger or Postman.
  4. Change a route URL or DTO property and save — test again in Swagger or curl.
  5. Return the wrong status code on purpose (404 instead of 200) and see what the client shows.

Remember

You understand ASP.NET Core Web API Main Method in plain language. You traced or ran working C# in ShopNest.API. Move on when you can teach this topic to a friend.

Interview prep for this lesson

Practice these questions aloud after reading—each links to a full structured answer.

Mid PDF Detailed
Explain how the POST method differs from GET.
Short answer: GET → Used to retrieve data, should not modify server state, and can be cached/bookmarked. POST → Used to create new resources or submit data. It modifies server state, is not idempotent, and cannot be cach…
Mid PDF Detailed
Why is the HTTP GET method considered safe and idempotent?
Short answer: Safe → Because it only retrieves data without modifying server state. Idempotent → Multiple GET requests have the same result; no side effects occur. Real-world example (ShopNest) Creating an order is POST…
Mid PDF Detailed
Can the PUT method be used to create a resource in REST APIs?
Short answer: Yes. If the resource does not exist, PUT can create it at the specified URI. Example: 👉 PUT /users/100 → If user 100 doesn’t exist, it will be created. Real-world example (ShopNest) Creating an order is PO…
Junior PDF Detailed
What is the idempotency of HTTP methods, and how does it apply to PUT or DELETE?
Short answer: Idempotency means multiple identical requests have the same effect as one. PUT → Updating a resource with the same data multiple times results in no further change. DELETE → Deleting a resource repeatedly s…
Mid PDF Detailed
How does the PATCH method work differently from PUT?
Short answer: PATCH → Updates only the specified fields (partial update). PUT → Replaces the entire resource representation. 👉 Example code PATCH /users/1 { "email": "new@email.com" } → Updates only…
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ASP.NET Core Web API Tutorial
Course syllabus

ASP.NET Core Web API Tutorial

Module 1: Introduction and Environment Setup
Module 2: Web API Basics
Module 3: Routing
Module 4: Return Types and Status Codes
Module 5: Model Binding
Module 6: Entity Framework Core
Module 7: AutoMapper and Mapperly
Module 8: HTTP Methods
Module 9: Logging
Module 10: Caching
Module 11: FluentValidation
Module 12: Filters
Module 13: Security
Module 14: API Versioning
Module 15: Repository Pattern
Module 16: E-Commerce Real-Time Application
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