//Шапка для Rest
[HttpGet]
[Route("Rieltor/{id}")]
public тип название(id)
[HttpPost]
[Route("Rieltor")]
public тип название([FromBody]Тип переменная)
  config.Formatters.Clear();
            config.Formatters.Add(new System.Net.Http.Formatting.JsonMediaTypeFormatter());
//клиент рест
using RestSharp;
  var client = new RestClient("http://localhost:8553/rielt/2");
            var request = new RestRequest(Method.GET);
            request.AddHeader("GET", "application/json");
            request.OnBeforeDeserialization = resp => { resp.ContentType = "application/json"; };
            var response = client.Execute<Rielt>(request);
//WCF callback
[ServiceContract(CallbackContract = typeof(IService1Callback), SessionMode = SessionMode.Required)]
    public interface IService1
    {
        [OperationContract(IsOneWay = true)]
        void CalcSal(string name);
    }
    public interface IService1Callback
    {
        [OperationContract(IsOneWay = true)]
        void CalcSalCallback(int sum);
    }
public void CalcSal(string name)        {
            foreach (salary s in salary_list)
           //
            var callback = OperationContext.Current.GetCallbackChannel<IService1Callback>();
            callback.CalcSalCallback(sum);        }
//Клиент
 public Form1()        {
            InitializeComponent();
            ServiceCallback callback = new ServiceCallback();
            callback.FormEvent += Calc;
            InstanceContext context = new InstanceContext(callback);
            cl = new ServiceReference2.Service1Client(context);        }
public void Calc(int sum)
        {  MessageBox.Show(Convert.ToString(sum));}
        public class ServiceCallback :ServiceReference2.IService1Callback        {
            public delegate void FormDelegate(int sum);
            public event FormDelegate FormEvent;
            public void CalcSalCallback(int sum)
            {                FormEvent?.Invoke(sum);            }        }
//webconfig
 <services>
      <service name="TestCallBack.Service1" >
        <endpoint address="" binding="wsDualHttpBinding" contract="TestCallBack.IService1"></endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"></endpoint>
      </service>
    </services>