To develop an HTTP API with minimal dependencies prior to .NET Core 6.0, you can follow these steps:

1. Choose a Lightweight Framework
   Use ASP.NET Core (preferably version 2.1 or higher). It’s lightweight and designed for building HTTP APIs.
2. Set Up Your Project
   Create a new ASP.NET Core Web API project:
   dotnet new webapi -n YourApiName
   This creates a basic project structure with minimal dependencies.
3. Define Your Models
   Create simple data models representing the resources your API will handle. For example:
   public class Product
   {
   public int Id { get; set; }
   public string Name { get; set; }
   public decimal Price { get; set; }
   }
4. Create Controllers
   Create a controller to handle HTTP requests. For example:
   [ApiController]
   [Route(\”api\/[controller]\”)]
   public class ProductsController : ControllerBase
   {
   private static List products = new List();
   [HttpGet]
   public ActionResult> GetProducts()
   {

    return Ok(products);

   }
   [HttpPost]
   public ActionResult CreateProduct(Product product)
   {

    products.Add(product);
    return CreatedAtAction(nameof(GetProducts), new { id = product.Id }, product);

   }
   }
5. Configure Routing and Middleware
   In Startup.cs, configure routing and any necessary middleware:
   public void ConfigureServices(IServiceCollection services)
   {
   services.AddControllers();
   }
   public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
   {
   if (env.IsDevelopment())
   {

    app.UseDeveloperExceptionPage();

   }
   app.UseRouting();
   app.UseEndpoints(endpoints =>
   {

    endpoints.MapControllers();

   });
   }
6. Run and Test Your API
   Run your API using:
   dotnet run
   Use tools like Postman or curl to test the endpoints.
7. Document Your API
   Consider using Swagger for API documentation. Add the following NuGet package:
   dotnet add package Swashbuckle.AspNetCore
   Configure Swagger in Startup.cs to generate documentation.
8. Deployment
   Choose your hosting environment (e.g., Azure, AWS, or on-premises) and deploy your application as needed.