Minimal APIs: Fast, Lean, and Powerful in ASP.NET Core

Sometimes you don’t need the full MVC setup — you just want to expose a few endpoints quickly and cleanly. That’s where Minimal APIs shine in ASP.NET Core.

In this post, we’ll explore how to create Minimal APIs that are fast, lean, and production-ready.

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🚀 What Are Minimal APIs?

Minimal APIs allow you to define endpoints without controllers or attributes. You write route handlers directly in Program.cs using clean, expressive syntax.

Perfect for:

• Microservices
• Internal tools
• Prototypes
• Lightweight APIs

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🛠️ Creating a Minimal API Project

dotnet new web -n MinimalApiDemo
cd MinimalApiDemo
dotnet run

This template has no controllers — just a single Program.cs.

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🧱 Basic Example

var app = WebApplication.Create(args);

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

app.MapGet("/api/products", () =>
{
    var products = new[] {
        new { Id = 1, Name = "Apple" },
        new { Id = 2, Name = "Orange" }
    };
    return Results.Ok(products);
});

app.Run();

✅ No controller classes. Just functions.

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📦 Dependency Injection Still Works

app.MapGet("/config", (IConfiguration config) =>
{
    var appName = config["AppName"];
    return Results.Ok(new { appName });
});

You can inject any service registered in the DI container.

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🔐 Add Authentication & Authorization

app.MapGet("/secure", [Authorize] () => "Secure data");

Minimal APIs fully support [Authorize], Swagger, CORS, and all major ASP.NET Core features.

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🧩 Grouping Routes (Optional)

For better structure, group endpoints:

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

products.MapGet("/", GetAllProducts);
products.MapPost("/", CreateProduct);

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🧪 Swagger for Minimal APIs

Add these in Program.cs:

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

app.UseSwagger();
app.UseSwaggerUI();

It works just like regular APIs!

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⚠️ When Not to Use Minimal APIs

• When your app grows and needs organized controllers/services
• When using lots of filters or custom attributes
• When you want a strong separation of concerns

Minimal APIs are great, but don't replace MVC entirely.

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✅ Up Next

Next: background tasks and scheduled jobs using IHostedService and Hangfire.

➡️ Background Tasks & Hosted Services →

Small APIs. Big power. Let’s go! 🔥