Have you participated in developing custom service applications or systems?

Yes, within projects I have created my own service applications. For example, I developed a REST API in C# using ASP.NET Core for handling requests and interacting with a database.

Example of a simple service in C#:

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    private readonly IProductService _service;

    public ProductsController(IProductService service)
    {
        _service = service;
    }

    [HttpGet]
    public IEnumerable<Product> GetAll()
    {
        return _service.GetAllProducts();
    }
}

This service handles HTTP requests, interacts with business logic, and returns data to the client.