Minimal APIs vs Controllers in ASP.NET Core: Which One Should You Use?

Do you really need controllers to build a REST API in ASP.NET Core?

For years, controllers have been the standard approach to building APIs in ASP.NET Core. But Minimal APIs offer a simpler alternative with less boilerplate and a more direct way to define endpoints.

So, what's the difference, and when should you use each?

Let's break it down.

What Are Minimal APIs?

Minimal APIs allow you to build HTTP APIs with minimal setup and fewer abstractions.

Instead of creating controllers and action methods, you define your endpoints directly in your application.

Example:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/users", () =>
{
    return new[]
    {
        new { Id = 1, Name = "Ahmed" },
        new { Id = 2, Name = "John" }
    };
});

app.Run();

That's it. You've created a GET endpoint without a controller.

Minimal APIs are particularly useful for small services, microservices, lightweight APIs, and applications where simplicity matters.

What Are Controllers?

Controllers are a more structured approach to building APIs in ASP.NET Core.

They group related endpoints into classes, with each endpoint represented by an action method.

Example:

[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    [HttpGet]
    public IActionResult GetUsers()
    {
        var users = new[]
        {
            new { Id = 1, Name = "Ahmed" },
            new { Id = 2, Name = "John" }
        };

        return Ok(users);
    }
}

To use this controller, you also need to register controller services and map the controller routes in your application setup.

Controllers provide a familiar structure for organizing endpoints, especially as an API grows in complexity.

Minimal APIs vs Controllers: Key Differences

Feature	Minimal APIs	Controllers
Setup	Simple and lightweight	Requires more configuration
Boilerplate	Minimal	More structured code
Organization	Endpoint-based, often grouped with route groups	Class-based organization
Flexibility	Supports filters, binding, and other extensibility features	Supports a broad range of MVC features
Validation	Supports endpoint filters and validation approaches	Integrates with MVC validation and model-state behavior
Best suited for	Lightweight APIs and focused services	Large APIs with established MVC patterns

Neither approach is inherently better. The right choice depends on your application's requirements and your preferred architecture.

When Should You Use Minimal APIs?

Minimal APIs are a good fit when:

• You're building small services or microservices.
• You want to reduce boilerplate and get endpoints running quickly.
• Your API has relatively straightforward request-handling logic.
• You prefer defining endpoints explicitly and grouping related routes with MapGroup().

For example, a simple URL shortener API could use Minimal APIs to handle URL creation, redirection, and basic analytics without introducing unnecessary controller classes.

However, Minimal APIs can become difficult to maintain if you put too much business logic directly inside endpoint handlers.

Keep handlers focused and move business logic into services.

When Should You Use Controllers?

Controllers make sense when:

• You're building a large API with many related endpoints.
• Your team prefers class-based organization.
• You need established MVC features and conventions.
• Your application already follows a controller-based architecture.

For example, an e-commerce API with separate areas for products, orders, payments, and customers can benefit from organizing related endpoints into dedicated controllers.

Controllers don't automatically make an application scalable or maintainable, though. Good separation of concerns and thoughtful architecture still matter.

Can You Use Both?

Yes.

ASP.NET Core supports Minimal APIs and controllers in the same application.

You could use controllers for complex business resources while using Minimal APIs for lightweight health checks, internal endpoints, or smaller features.

This gives you flexibility without forcing your entire application into one approach.

Final Takeaway

Minimal APIs and controllers solve the same fundamental problem: handling HTTP requests and returning responses.

Minimal APIs prioritize simplicity and less boilerplate, while controllers provide a familiar, class-based structure with the broader MVC feature set.

Don't choose based on which approach has fewer lines of code. Choose based on what makes your application easier to build, test, extend, and maintain.