Creating a clean, well-documented CRUD API is a foundational skill for modern backend development. In this guide, we’ll walk through a production-ready Product CRUD API built with ASP.NET Core Web API (.NET 10, C# 14)—covering design principles, full controller logic, testing, Swagger integration, and clear next steps for scaling to production.

Overview

What you’ll get

Typical use cases

{ 

    public class Product 

    { 

        public int Id { get; set; } 

        public string? Name { get; set; } 

        public string? Description { get; set; } 

        public decimal Price { get; set; } 

        public int Stock { get; set; } 

        public string? Category { get; set; } 

    } 

} 

Why this design?

{ 
    [ApiController] 
    [Route("[controller]")] 
    public class ProductController : ControllerBase 
    { 
        private static List<Product> _products = new(); 
        private static int _nextId = 1; 
        [HttpGet(Name = "GetProducts")] 
        public ActionResult<IEnumerable<Product>> Get() 
        { 
            return Ok(_products); 
        } 
        [HttpGet("{id}", Name = "GetProductById")] 
        public ActionResult<Product> GetById(int id) 
        { 
            var product = _products.FirstOrDefault(p => p.Id == id); 
            return product == null ? NotFound() : Ok(product); 
        } 
        [HttpPost(Name = "CreateProduct")] 
        public ActionResult<Product> Create([FromBody] Product product) 
        { 
            product.Id = _nextId++; 
            _products.Add(product); 
            return CreatedAtRoute("GetProductById", new { id = product.Id }, product); 
        } 
        [HttpPut("{id}", Name = "UpdateProduct")] 
        public ActionResult<Product> Update(int id, [FromBody] Product product) 
        { 
            var existing = _products.FirstOrDefault(p => p.Id == id); 
            if (existing == null) return NotFound(); 
            existing.Name = product.Name; 
            existing.Description = product.Description; 
            existing.Price = product.Price; 
            existing.Stock = product.Stock; 
            existing.Category = product.Category; 
            return Ok(existing); 
        } 
        [HttpDelete("{id}", Name = "DeleteProduct")] 
        public ActionResult Delete(int id) 
        { 
            var product = _products.FirstOrDefault(p => p.Id == id); 
            if (product == null) return NotFound(); 
            _products.Remove(product); 
            return NoContent(); 
        } 
    } 
} 

Key highlights

Create (POST /product)

Read All (GET /product)

Read by ID (GET /product/{id})

Update (PUT /product/{id})

Delete (DELETE /product/{id})

API Endpoints

Method       Endpoint     Description 
GET          /product         Get all products
GET          /product/{id}   Get product by ID
POST       /product          Create a new product
PUT         /product/{id}   Update a product
DELETE    /product/{id}      Delete a product

Testing Options 

Swagger Setup (Program.cs)

var builder = WebApplication.CreateBuilder(args); 
builder.Services.AddControllers(); 
builder.Services.AddEndpointsApiExplorer(); 
builder.Services.AddSwaggerGen(); 
var app = builder.Build(); 
app.UseSwagger(); 
app.UseSwaggerUI(); 
app.UseHttpsRedirection(); 
app.UseAuthorization(); 
app.MapControllers(); 
app.Run(); 

Best Practices Used

Recommended for Production

Production Enhancements (What to Add Next)

Troubleshooting Tips

Final Thoughts