var contracts = new JsonRpcContractResolver(); var serializer = new JsonRpcSerializer(contracts); contracts.AddResponseContract("sum", new JsonRpcResponseContract(typeof(long))); var request = new JsonRpcRequest(1L, "sum", new[] { 1L, 2L }); var requestString = serializer.SerializeRequest(request); // ... contracts.AddResponseBinding(request.Id, request.Method); var responseData = serializer.DeserializeResponseData(responseString); var response = responseData.Item.Message; Console.WriteLine((long)response.Result);