C# Minimal APIs in .NET 9: High-Throughput Microservice Architecture

By Elena Rostova • Intermediate • 12 min read • Updated 2026-09-11

What You Will Master in This Tutorial

Configure a streamlined web application using WebApplication.CreateBuilder().
Implement endpoint filters for cross-cutting authentication and validation.
Leverage TypedResults<T> for compile-time verified HTTP responses.

1. Building the Endpoint Pipeline

Minimal APIs discard traditional controller boilerplate, enabling concise route definition with direct lambda mapping and automatic model binding.

CSHARP

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

app.MapGet("/api/health", () => TypedResults.Ok(new { Status = "Healthy", Timestamp = DateTime.UtcNow }));

app.MapPost("/api/items", (CreateItemRequest request, IItemRepository repo) => {
    var created = repo.Add(request);
    return TypedResults.Created($"/api/items/{created.Id}", created);
});

app.Run();

Note: TypedResults enables rich OpenAPI documentation and unit testability without spinning up a test server.

Knowledge Check: Test Your Understanding

1. What is the primary architectural advantage of Minimal APIs over MVC Controllers?

Frequently Asked Questions

Can I use Entity Framework Core with Minimal APIs?

Yes, EF Core integrates seamlessly via standard dependency injection by injecting your DbContext directly into route handler parameters.