Building High-Performance APIs with Minimal APIs and .NET 10

Introduction

Modern applications demand APIs that are fast, scalable, and easy to maintain. Whether you're building microservices, cloud-native applications, mobile backends, or AI-powered systems, API performance directly impacts user experience and infrastructure costs.

For years, ASP.NET Core controllers have been the standard approach for building APIs in .NET. While controllers remain an excellent choice for large and complex applications, many APIs don't require the full MVC framework. To address this, Microsoft introduced Minimal APIs, a lightweight approach that reduces boilerplate code while delivering excellent performance.

With .NET 10 continuing to improve runtime efficiency, startup performance, and developer productivity, Minimal APIs have become an attractive option for teams building modern high-performance services.

In this article, you'll learn what Minimal APIs are, why they're fast, how to build production-ready APIs using .NET 10, and the best practices developers should follow.

What Are Minimal APIs?

Minimal APIs provide a simplified way to create HTTP endpoints in ASP.NET Core without using controllers.

Traditional controller-based APIs often require:

Controllers
Route attributes
Action methods
Dependency injection setup
Additional boilerplate code

Example:

[ApiController]
[Route("api/products")]
public class ProductsController : ControllerBase
{
    [HttpGet]
    public IActionResult Get()
    {
        return Ok();
    }
}

With Minimal APIs, the same endpoint can be created using:

var app = builder.Build();

app.MapGet("/products", () =>
{
    return Results.Ok();
});

app.Run();

The code is shorter, easier to read, and often easier to maintain for smaller services.

Why Minimal APIs Are High Performance

Minimal APIs remove some of the overhead associated with the MVC pipeline.

Benefits include:

Faster startup times
Reduced memory usage
Lower request-processing overhead
Simpler request pipelines

The request flow becomes:

Client
   ↓
Minimal API Endpoint
   ↓
Response

Instead of:

Client
   ↓
Routing
   ↓
Controller
   ↓
Action
   ↓
Response

While the difference may be small for low-traffic applications, it becomes more noticeable in high-throughput environments.

Creating a Minimal API Project

Create a new project:

dotnet new web -n ProductApi

The generated application is intentionally simple.

Basic setup:

var builder = WebApplication.CreateBuilder(args);

var app = builder.Build();

app.MapGet("/", () => "Hello World");

app.Run();

This minimal configuration provides a strong foundation for building APIs quickly.

Building CRUD Endpoints

Consider a simple product model.

public record Product(
    int Id,
    string Name,
    decimal Price);

Sample data:

var products = new List<Product>
{
    new(1, "Laptop", 50000),
    new(2, "Keyboard", 2000)
};

Retrieve all products:

app.MapGet("/products", () =>
{
    return products;
});

Retrieve a single product:

app.MapGet("/products/{id}", (int id) =>
{
    return products.FirstOrDefault(
        p => p.Id == id);
});

Create a product:

app.MapPost("/products",
    (Product product) =>
{
    products.Add(product);

    return Results.Created(
        $"/products/{product.Id}",
        product);
});

Minimal APIs make CRUD development straightforward while keeping code concise.

Dependency Injection Support

Minimal APIs fully support dependency injection.

Example service:

public class ProductService
{
    public IEnumerable<Product> GetProducts()
    {
        return
        [
            new Product(1, "Laptop", 50000)
        ];
    }
}

builder.Services.AddScoped<ProductService>();

Use it inside an endpoint:

app.MapGet("/products",
    (ProductService service) =>
{
    return service.GetProducts();
});

This allows developers to maintain clean architecture principles while benefiting from Minimal APIs.

Input Validation

Validation remains important for production applications.

Example request model:

public record CreateProductRequest(
    string Name,
    decimal Price);

Simple validation:

app.MapPost("/products",
    (CreateProductRequest request) =>
{
    if (string.IsNullOrWhiteSpace(
        request.Name))
    {
        return Results.BadRequest(
            "Name is required");
    }

    return Results.Ok();
});

For larger applications, FluentValidation or endpoint filters can be used to centralize validation logic.

Route Groups for Better Organization

As APIs grow, organizing endpoints becomes important.

Route groups provide a clean structure.

var products =
    app.MapGroup("/products");

Define endpoints:

products.MapGet("/", () =>
{
    return Results.Ok();
});

products.MapPost("/", () =>
{
    return Results.Ok();
});

Benefits include:

Cleaner code organization
Shared configuration
Easier maintenance

Route groups help prevent Minimal APIs from becoming difficult to manage as applications scale.

Built-In OpenAPI Support

API documentation is essential for modern applications.

Enable OpenAPI:

builder.Services.AddOpenApi();

Map OpenAPI:

app.MapOpenApi();

Developers can then generate documentation automatically for API consumers.

This improves developer experience and simplifies integration efforts.

Performance Optimization Techniques

Minimal APIs are already efficient, but additional optimizations can improve performance further.

Use Asynchronous Operations

Example:

app.MapGet("/products",
    async (ProductService service) =>
{
    return await service.GetProductsAsync();
});

Asynchronous operations improve scalability under load.

Leverage Caching

Frequently requested data should be cached whenever possible.

Benefits include:

Faster responses
Reduced database load
Improved throughput

Return Typed Results

Example:

app.MapGet("/health",
    () => TypedResults.Ok());

Typed results provide better compile-time safety and can improve API documentation generation.

Avoid Unnecessary Allocations

Reduce object creation inside high-traffic endpoints whenever possible.

Small optimizations become significant at scale.

Minimal APIs vs Controllers

Feature	Minimal APIs	Controllers
Boilerplate	Low	Higher
Startup Performance	Faster	Good
Simplicity	Excellent	Moderate
Large Applications	Moderate	Excellent
Learning Curve	Easier	Moderate
API Development Speed	Faster	Good
Organization for Complex APIs	Moderate	Strong

Controllers remain valuable for large enterprise applications, while Minimal APIs excel in lightweight and microservice-oriented scenarios.

Best Use Cases

Minimal APIs are particularly effective for:

Microservices
Serverless APIs
Internal services
High-performance APIs
Cloud-native applications
Backend-for-Frontend (BFF) services
AI service endpoints

These scenarios benefit from reduced complexity and improved performance.

Best Practices

Keep Endpoints Focused

Each endpoint should perform a single responsibility.

Avoid large amounts of business logic directly inside endpoint definitions.

Use Dependency Injection

Move business logic into services rather than embedding it inside route handlers.

Organize with Route Groups

As applications grow, route groups help maintain readability and structure.

Implement Proper Validation

Validate all incoming data before processing requests.

Monitor Performance

Track:

Request latency
Error rates
Throughput
Resource usage

Observability remains critical even for lightweight APIs.

Choose Controllers When Necessary

Minimal APIs are not a replacement for every scenario.

For large applications with extensive routing and complex workflows, controllers may still be the better choice.

Conclusion

Minimal APIs have become one of the most compelling features in modern ASP.NET Core development. By reducing boilerplate, simplifying endpoint creation, and improving performance, they enable developers to build lightweight and efficient APIs with minimal effort.

Combined with the performance enhancements in .NET 10, Minimal APIs provide an excellent foundation for microservices, cloud-native applications, internal services, and high-throughput systems. They offer a clean and productive development experience while maintaining full access to ASP.NET Core features such as dependency injection, validation, authentication, and OpenAPI integration.

For teams seeking to build fast, scalable, and maintainable APIs, Minimal APIs represent a practical and modern approach that aligns well with today's application architectures.