using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""user_id"": ""something_name"",

              ""devices"": {

                """": {

                  ""sessions"": [

                    {

                      ""connections"": [

                        {

                          ""ip"": ""225.225.225.225"",

                          ""user_agent"": ""something"",

                          ""last_seen"": 1504266816737

                        }

                      ]

                    }

                  ]

                }

              }

            }";

        dynamic values = JsonConvert.DeserializeObject<dynamic>(json);

        dynamic ip = values.devices[""].sessions[0].connections[0].ip;

        Console.WriteLine("ip: " + ip);

    }

}