Minimal API CRUD in .NET 10 step by step

Minimal API CRUD in .NET 10 Step by Step

In this article, we will build a complete CRUD (Create, Read, Update, Delete) application using Minimal APIs in .NET 10. Minimal APIs allow you to create lightweight and fast web APIs with less code and better performance.

• Create ASP.NET Core Minimal API Project
• Create Model Class
• Setup In-Memory Database
• Create CRUD Endpoints
• Test API using Browser / Swagger

Step 1 : Create Project

Create a new Minimal API project using .NET CLI:

dotnet new web -n MinimalApiDemo
cd MinimalApiDemo

Step 2 : Create Model Class (Product.cs)

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public double Price { get; set; }
}

This model represents the data we will store and manipulate.

Step 3 : Setup In-Memory Data

Instead of using a database, we will use a simple in-memory list.

List<Product> products = new List<Product>()
{
    new Product { Id = 1, Name = "Laptop", Price = 1000 },
    new Product { Id = 2, Name = "Mobile", Price = 500 }
};

Step 4 : Create CRUD APIs (Program.cs)

Open Program.cs and write the following code:

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

List<Product> products = new List<Product>()
{
    new Product { Id = 1, Name = "Laptop", Price = 1000 },
    new Product { Id = 2, Name = "Mobile", Price = 500 }
};

// GET ALL
app.MapGet("/products", () => products);

// GET BY ID
app.MapGet("/products/{id}", (int id) =>
{
    var product = products.FirstOrDefault(x => x.Id == id);
    return product is not null ? Results.Ok(product) : Results.NotFound();
});

// CREATE
app.MapPost("/products", (Product product) =>
{
    product.Id = products.Max(x => x.Id) + 1;
    products.Add(product);
    return Results.Created($"/products/{product.Id}", product);
});

// UPDATE
app.MapPut("/products/{id}", (int id, Product updatedProduct) =>
{
    var product = products.FirstOrDefault(x => x.Id == id);

    if (product is null)
        return Results.NotFound();

    product.Name = updatedProduct.Name;
    product.Price = updatedProduct.Price;

    return Results.Ok(product);
});

// DELETE
app.MapDelete("/products/{id}", (int id) =>
{
    var product = products.FirstOrDefault(x => x.Id == id);

    if (product is null)
        return Results.NotFound();

    products.Remove(product);
    return Results.Ok();
});

app.Run();

Step 5 : Run the Application

dotnet run

Open browser:

• GET All → http://localhost:5000/products
• GET By Id → http://localhost:5000/products/1

Testing using JSON

POST /products
{
  "name": "Tablet",
  "price": 300
}

PUT /products/1
{
  "name": "Updated Laptop",
  "price": 1200
}

DELETE /products/1

Note : This example uses in-memory data. For real applications, use Entity Framework Core with SQL Server.

Conclusion

In this article, we learned how to build a complete CRUD API using Minimal APIs in .NET 10. Minimal APIs reduce boilerplate code and make development faster. You can extend this example by adding database support, authentication, and validation.