mid.NET Core

What are minimal APIs in .NET Core?

Updated Apr 28, 2026

Short answer

Minimal APIs in .NET (6 and above) are a simplified way to build HTTP APIs with minimal boilerplate code, allowing developers to define endpoints directly in Program.cs without controllers, making them lightweight, fast, and easy to use.

Deep explanation

Traditional ASP.NET Core APIs use:

  • Controllers
  • Attributes ([HttpGet], [Route])
  • Multiple files and configurations

Minimal APIs remove this complexity and let you define endpoints directly in code using simple routing functions.

They were introduced in .NET 6 as part of the effort to:

  • Reduce boilerplate code
  • Improve startup performance
  • Simplify microservice development
  • Make APIs more readable for small services

---

🔷 Key Characteristics of Minimal APIs

✔ 1. No Controllers Required

You define routes directly in Program.cs.

✔ 2. Lightweight and Fast

  • Less overhead than MVC pipeline
  • Faster startup time

✔ 3. Built for Microservices

  • Ideal for small, focused APIs
  • Easy to deploy independently

✔ 4. Fully Supports .NET Features

  • Dependency Injection
  • Middleware
  • Authentication/Authorization
  • Model binding

---

🧩 Example of Minimal API

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


app.MapGet("/hello", () =>
{
    return "Hello from Minimal API";
});


app.MapGet("/users/{id}", (int id) =>
{
    return $"User ID: {id}";
});


app.Run();

🧠 How It Works (Flow)

TypeScript
Client Request
      ↓
Minimal API Endpoint (Program.cs)
      ↓
Delegate / Lambda Execution
      ↓
Response Returned Immediately

Real-world example

Imagine building a weather microservice:

Using Controllers:

  • Create Controller class
  • Define multiple files
  • Add attributes and routing

Using Minimal APIs:

You simply do:

CSHARP
app.MapGet("/weather", () =>
{
    return new[] { "Sunny", "Cloudy", "Rainy" };
});

Common mistakes

  • * Using Minimal APIs for very large enterprise systems without structure
  • * Mixing too much business logic inside `Program.cs`
  • * Assuming Minimal APIs don’t support authentication or middleware (they do)
  • * Confusing “minimal code” with “minimal capability”
  • * Not organizing endpoints in separate extension methods for large apps
  • ## 🟡 When to Use Minimal APIs
  • - ✔ Microservices
  • - ✔ Lightweight REST APIs
  • - ✔ Prototypes / MVPs
  • - ✔ Internal tools
  • - ✔ High-performance APIs
  • ## 🟡 When NOT to Use
  • - ❌ Very large enterprise applications with complex layering
  • - ❌ Heavy MVC-based applications with views and controllers
  • - ❌ Systems requiring strict separation of concerns at scale

Follow-up questions

  • What is the difference between Minimal APIs and MVC controllers?
  • Can Minimal APIs support authentication and authorization?
  • How do you structure large Minimal API projects?
  • Are Minimal APIs faster than controllers? Why?
  • Can we use dependency injection in Minimal APIs?

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