diff --git a/source/Trek-12/DataContractPersistence/DataContractJson.cs b/source/Trek-12/DataContractPersistence/DataContractJson.cs
new file mode 100644
index 0000000..83f745a
--- /dev/null
+++ b/source/Trek-12/DataContractPersistence/DataContractJson.cs
@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.Serialization;
+using System.Text;
+using System.Threading.Tasks;
+using System.Xml;
+using System.Runtime.Serialization.Json;
+using System.IO;
+using System.Xml.Serialization;
+using System.Collections.ObjectModel;
+using System.Text.Json;
+using Models.Game;
+using Models.Interfaces;
+
+namespace DataContractPersistence
+{
+    public class DataContractJson : IPersistence
+    {
+        /// <summary>
+        /// Name of the file where the data will be saved
+        /// </summary>
+        public string FileName { get; set; } = "data.json";
+
+        /// <summary>
+        /// Path (relative to the project)
+        /// </summary>
+        public string FilePath { get; set; } = Path.Combine(AppDomain.CurrentDomain.BaseDirectory);
+
+        /// <summary>
+        /// Load all the data from JSON file
+        /// </summary>
+        /// <returns>A tuple with the lists of players, games, maps and best scores</returns>
+        public (List<Player>, List<Game>, List<Map>, List<BestScore>) LoadData()
+        {
+            var JsonSerializer = new DataContractJsonSerializer(typeof(DataToPersist));
+            DataToPersist? data = new DataToPersist();
+
+            using (Stream s = File.OpenRead(Path.Combine(FilePath, FileName)))
+            {
+                data = JsonSerializer.ReadObject(s) as DataToPersist;
+            }
+            Console.WriteLine("Data loaded: " + Path.Combine(FilePath, FileName));
+            return (data.Players, data.Games, data.Maps, data.BestScores);
+        }
+
+        /// <summary>
+        /// Save all the data to a JSON file
+        /// </summary>
+        /// <param name="players"></param>
+        /// <param name="games"></param>
+        /// <param name="maps"></param>
+        /// <param name="bestScores"></param>
+        public void SaveData(List<Player> players, List<Game> games, List<Map> maps, List<BestScore> bestScores)
+        {
+            if (!Directory.Exists(FilePath))
+            {
+                Debug.WriteLine("Directory created");
+                Debug.WriteLine(Directory.GetDirectoryRoot(FilePath));
+                Debug.WriteLine(FilePath);
+                Directory.CreateDirectory(FilePath);
+            }
+
+            var JsonSerializer = new DataContractJsonSerializer(typeof(DataToPersist));
+            DataToPersist? data = new DataToPersist();
+
+            data.Players = players;
+            data.Games = games;
+            data.Maps = maps;
+            data.BestScores = bestScores;
+
+            var settings = new XmlWriterSettings() { Indent = true };
+            using (FileStream stream = File.Create(Path.Combine(FilePath, FileName)))
+            {
+                using (var writer = JsonReaderWriterFactory.CreateJsonWriter(
+                           stream,
+                           Encoding.UTF8,
+                           false,
+                           true))
+                {
+                    JsonSerializer.WriteObject(writer, data);
+                    writer.Flush();
+                }
+            }
+        }
+    }
+}
diff --git a/source/Trek-12/DataContractPersistence/DataContractXml.cs b/source/Trek-12/DataContractPersistence/DataContractXml.cs
index 81598c3..e09489d 100644
--- a/source/Trek-12/DataContractPersistence/DataContractXml.cs
+++ b/source/Trek-12/DataContractPersistence/DataContractXml.cs
@@ -15,9 +15,20 @@ namespace DataContractPersistence
 {
     public class DataContractXml : IPersistence
     {
+        /// <summary>
+        /// Name of the file where the data will be saved
+        /// </summary>
         public string FileName { get; set; } = "data.xml";
+
+        /// <summary>
+        /// Path (relative to the project)
+        /// </summary>
         public string FilePath { get; set; } = Path.Combine(AppDomain.CurrentDomain.BaseDirectory);
 
+        /// <summary>
+        /// Load all the data from XML file
+        /// </summary>
+        /// <returns>A tuple with the lists of players, games, maps and best scores</returns>
         public (List<Player>, List<Game>, List<Map>, List<BestScore>) LoadData()
         {
             var serializer = new DataContractSerializer(typeof(DataToPersist));
@@ -31,6 +42,13 @@ namespace DataContractPersistence
             return (data.Players, data.Games, data.Maps, data.BestScores);
         }
 
+        /// <summary>
+        /// Save all the data to a XML file
+        /// </summary>
+        /// <param name="players"></param>
+        /// <param name="games"></param>
+        /// <param name="maps"></param>
+        /// <param name="bestScores"></param>
         public void SaveData(List<Player> players, List<Game> games, List<Map> maps, List<BestScore> bestScores)
         {
             if(!Directory.Exists(FilePath))
diff --git a/source/Trek-12/DataContractPersistence/DataToPersist.cs b/source/Trek-12/DataContractPersistence/DataToPersist.cs
index 9a8dad5..8aca714 100644
--- a/source/Trek-12/DataContractPersistence/DataToPersist.cs
+++ b/source/Trek-12/DataContractPersistence/DataToPersist.cs
@@ -5,9 +5,24 @@ namespace DataContractPersistence
 {
     public class DataToPersist
     {
+        /// <summary>
+        /// List of players
+        /// </summary>
         public List<Player> Players { get; set; }
+
+        /// <summary>
+        /// List of games (with all the data in it to be able to recreate the game)
+        /// </summary>
         public List<Game> Games { get; set; }
+
+        /// <summary>
+        /// List of maps with their boards
+        /// </summary>
         public List<Map> Maps { get; set; }
+
+        /// <summary>
+        /// List of best scores
+        /// </summary>
         public List<BestScore> BestScores { get; set; }
     }
 }
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