ProductController response = new ServiceResponse<List<Product>>() { // returns products implicitly from List<Product> // ( similar to a callback function) // i.e. - res(prodcuts) => use products Data = products } **** see builder for configureing ServiceResponse # Program.cs /** replaces createHostBuilder and all that */ var builder = WebApplication.CreateBuilder(args); var app = builder.Build() /** Configure -previously done in startup.cs */ builder.Services.AddScoped<ITodoRepository, TodoRepository>();