Why should you care?

Every ShopNest service (Order, Product, User) is a Web API. If HTTP routing, DI, and JSON binding are shaky, everything built on top wobbles.

See it live — copy this example

Create a Web API project (dotnet new webapi), paste the code, then run dotnet run.

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

var app = builder.Build();
app.UseSwagger();
app.UseSwaggerUI();

app.MapGet("/products/{id:int}", (int id) =>
{
    return Results.Ok(new { Id = id, Name = "Demo Keyboard", Price = 2499 });
});

app.Run();

Run Example »

Edit the code and click Run — like W3Schools Try it Yourself.

What happened?

• MapGet handles GET /products/5.
• Results.Ok returns JSON.
• Swagger gives you a test UI in the browser during development.

Try it yourself

1. dotnet new webapi -n LearnWebApi
2. Add the example to Program.cs.
3. dotnet run and open /swagger.
4. Change a string or route in the example and save — watch Swagger or the RabbitMQ Management UI update.
5. Break the code on purpose (remove a semicolon), read the error message, then fix it.

Remember

Web API = HTTP endpoints + JSON in ASP.NET Core. Use minimal APIs (MapGet/MapPost) or controllers — both are valid. Swagger helps you test without Postman on day one.

Real-world: Product catalog API

Flipkart product pages call Product.Api millions of times per day. GET /products/{id} must be fast, cacheable, and independent from checkout deploys.

Outcome: Product team ships catalog changes without touching Order service binaries.