Difference Between Web API and MVC in ASP.NET Core.

ASP.NET Core is a powerful framework developed by Microsoft that supports both Web APIs and MVC architecture. While they share many similarities in structure, configuration, and middleware, they serve different purposes and are used in distinct scenarios.

This article explains the key differences between ASP.NET Core Web API and ASP.NET Core MVC, their intended use cases, and how they are implemented.

What is ASP.NET Core MVC?

ASP.NET Core MVC (Model-View-Controller) is a framework for building dynamic web applications that return HTML views to the browser. It uses the MVC design pattern, where:

Model: Represents the application’s data and business logic.
View: Responsible for presenting the data (UI) to the user using Razor syntax.
Controller: Handles incoming HTTP requests, interacts with the model, and returns views or data.

Key Features of ASP.NET Core MVC

Built-in routing system (app.UseRouting(), MapControllerRoute)
Strong support for dependency injection
Tag Helpers and Razor views for dynamic HTML generation
Model binding and validation support
Supports RESTful API endpoints
Highly testable and modular architecture

Example Code:

public class HomeController : Controller
{
    public IActionResult Index()
    {
        return View();  // Returns the "Index.cshtml" view
    }
}

View (Index.cshtml)

<h1>Welcome to ASP.NET Core MVC</h1>

Use Cases

Web portals and dashboards
Admin panels
E-commerce websites
Content Management Systems (CMS)

2. What is ASP.NET Core Web API?

ASP.NET Core Web API is designed for building HTTP-based RESTful services that return data only, usually in the form of JSON or XML. There are no views involved — only data exchange between client and server.

Key Features of ASP.NET Core Web API

Returns data instead of views
Lightweight and high-performance
Uses standard HTTP methods: GET, POST, PUT, DELETE
Built-in support for model binding, validation, dependency injection, and routing
Easily integrated with Swagger for API documentation

Use Case:

Backend services for mobile apps, SPAs (Angular/React), or microservices
Systems that require JSON-based APIs
Server-to-server communication

Example Code:

Step 1: Create a Model.

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public double Price { get; set; }
}

Step 2: Create the Controller.

using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
using System.Linq;

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    private static List<Product> products = new List<Product>
    {
        new Product { Id = 1, Name = "Laptop", Price = 1200 },
        new Product { Id = 2, Name = "Phone", Price = 800 }
    };

    [HttpGet]
    public ActionResult<IEnumerable<Product>> GetAll()
    {
        return Ok(products);
    }

    [HttpGet("{id}")]
    public ActionResult<Product> GetById(int id)
    {
        var product = products.FirstOrDefault(p => p.Id == id);
        if (product == null)
            return NotFound();

        return Ok(product);
    }

    [HttpPost]
    public ActionResult AddProduct(Product newProduct)
    {
        products.Add(newProduct);
        return CreatedAtAction(nameof(GetById), new { id = newProduct.Id }, newProduct);
    }
}

Step 3: Configure the application (Program.cs)

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

var app = builder.Build();

app.MapControllers(); // Enables attribute routing for API

app.Run();

Testing the API

GET /api/products → Returns all products
GET /api/products/1 → Returns product with ID = 1
POST /api/products → Add a new product (via Postman or frontend)

ASP.NET Core Web API is ideal for building modern, scalable, and stateless RESTful services. It separates the UI from the logic and serves as the backend for many client apps.

Key Difference Between Web API and MVC in ASP.NET Core.

Aspect	ASP.NET Core MVC	ASP.NET Core Web API
Purpose	Build dynamic web applications with UI	Build RESTful services for data exchange
Output	Returns HTML views using Razor	Returns data like JSON or XML
View Engine	Uses Razor (.cshtml)	No view engine; returns data only
Return Type	Returns View(), PartialView()	Returns Ok(), NotFound(), Created(), etc.
[ApiController] attribute	Not used	Commonly used for automatic model binding and validation
Use Case	Websites, Admin dashboards, CMS	SPAs (Angular, React), Mobile apps, Microservices
Client	Browsers that render HTML	Frontend apps, Postman, mobile apps
HTTP Verbs	Mainly GET and POST	GET, POST, PUT, DELETE (RESTful)

While ASP.NET Core MVC and Web API share the same base framework and features like routing, middleware, and dependency injection, they serve different application layers. MVC is ideal for UI-based applications, whereas Web API is built for data exchange and service-based architectures.