diff --git a/MCTG/ConsoleApp/Program.cs b/MCTG/ConsoleApp/Program.cs
index ff09c71..cf6c460 100644
--- a/MCTG/ConsoleApp/Program.cs
+++ b/MCTG/ConsoleApp/Program.cs
@@ -9,7 +9,7 @@ string path = "";           // - path to the save file
 string strategy = "xml";    // - strategy is 'xml' or 'json' (/!\ this is case sensitive)
 
 MasterManager masterMgr;
-IDataManager dataManager = (strategy == "xml") ?
+IDataSerializer dataManager = (strategy == "xml") ?
       new DataContractXML(path)
     : new DataContractJSON(path);
 
diff --git a/MCTG/DataPersistence/DataContractJSON.cs b/MCTG/DataPersistence/DataContractJSON.cs
index 13879b7..b0ae42d 100644
--- a/MCTG/DataPersistence/DataContractJSON.cs
+++ b/MCTG/DataPersistence/DataContractJSON.cs
@@ -14,7 +14,7 @@ namespace DataPersistence
     /// <summary>
     /// Define a serializer to manage JSON files.
     /// </summary>
-    public class DataContractJSON : IDataManager
+    public class DataContractJSON : IDataSerializer
     {
         #region Attributes
         private string _jsonFolderPath;
diff --git a/MCTG/DataPersistence/DataContractXML.cs b/MCTG/DataPersistence/DataContractXML.cs
index 910d26d..053c4ac 100644
--- a/MCTG/DataPersistence/DataContractXML.cs
+++ b/MCTG/DataPersistence/DataContractXML.cs
@@ -13,7 +13,7 @@ namespace DataPersistence
     /// <summary>
     /// Define a serializer to manage XML files.
     /// </summary>
-    public class DataContractXML : IDataManager
+    public class DataContractXML : IDataSerializer
     {
         #region Attributes
         private string _xmlFolderPath;
diff --git a/MCTG/DataPersistence/Stubs.cs b/MCTG/DataPersistence/Stubs.cs
index a6fece1..b842202 100644
--- a/MCTG/DataPersistence/Stubs.cs
+++ b/MCTG/DataPersistence/Stubs.cs
@@ -10,7 +10,7 @@ namespace DataPersistence
     /// <summary>
     /// The subs class is a group of prefabricated object that can only be loaded. It only use is for testing.
     /// </summary>
-    public class Stubs : IDataManager
+    public class Stubs : IDataSerializer
     {
         public Dictionary<string, List<object>> Load()
         {
diff --git a/MCTG/Model/Managers/DataManager.cs b/MCTG/Model/Managers/DataManager.cs
index 8ff3ff6..299d99f 100644
--- a/MCTG/Model/Managers/DataManager.cs
+++ b/MCTG/Model/Managers/DataManager.cs
@@ -16,9 +16,9 @@ namespace Model
         /// <summary>
         /// The data manager injected that know how to serialize the data.
         /// <br/><remarks><i>The setter is actually public for testing purpose. It will be private after.</i></remarks>
-        /// <br/>See: <see cref="IDataManager"/>
+        /// <br/>See: <see cref="IDataSerializer"/>
         /// </summary>
-        public IDataManager Serializer { get; set; }
+        public IDataSerializer Serializer { get; set; }
 
         /// <summary>
         /// The collection of all data. Each line of this dictionary has the type of the data as it key and the data for values.
@@ -31,7 +31,7 @@ namespace Model
         /// Constructor of the DataManager class. Take a IDataManager that will provide methods for the serialisation of the data.
         /// </summary>
         /// <param name="dataMgr">The data manager that know how to serialize a file.</param>
-        public DataManager(IDataManager dataMgr)
+        public DataManager(IDataSerializer dataMgr)
         {
             Serializer = dataMgr;
             Data = Serializer.Load();
@@ -41,21 +41,21 @@ namespace Model
         #region Methods
         /// <summary>
         /// Reload the data. Useful to update new data written in the save file.
-        /// <br/>See: <see cref="IDataManager.Load"/>
+        /// <br/>See: <see cref="IDataSerializer.Load"/>
         /// </summary>
         public void Reload()
             => Data = Serializer.Load();
 
         /// <summary>
         /// Save the data. Call the Save method of the serializer.
-        /// <br/>See: <see cref="IDataManager.Save(Dictionary{string, List{object}})"/>
+        /// <br/>See: <see cref="IDataSerializer.Save(Dictionary{string, List{object}})"/>
         /// </summary>
         public void Save()
             => Serializer.Save(Data);
 
         /// <summary>
         /// Import data from a file.
-        /// <br/>See: <see cref="IDataManager.Import{T}(string)"/>
+        /// <br/>See: <see cref="IDataSerializer.Import{T}(string)"/>
         /// </summary>
         /// <typeparam name="T">The type of data to import.</typeparam>
         /// <param name="pathOfTheFile">The path containing the name of the file created.</param>
@@ -68,7 +68,7 @@ namespace Model
 
         /// <summary>
         /// Export the data from the collection of data.
-        /// <br/>See: <see cref="IDataManager.Export{T}(T, string)"/>
+        /// <br/>See: <see cref="IDataSerializer.Export{T}(T, string)"/>
         /// </summary>
         /// <typeparam name="T">The type of data to export</typeparam>
         /// <param name="obj">The object to export</param>
diff --git a/MCTG/Model/Managers/IDataManager.cs b/MCTG/Model/Managers/IDataManager.cs
index c8a4ca6..ffb1aee 100644
--- a/MCTG/Model/Managers/IDataManager.cs
+++ b/MCTG/Model/Managers/IDataManager.cs
@@ -1,44 +1,17 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Model
-{
-    /// <summary>
-    /// Interface that define the methods of a data serializer.
-    /// </summary>
-    public interface IDataManager
-    {
-        /// <summary>
-        /// Save all the data in a file.
-        /// </summary>
-        /// <param name="elements">The data to save.</param>
-        void Save(Dictionary<string, List<object>> elements);
-
-        /// <summary>
-        /// Load all the data from a file.
-        /// </summary>
-        /// <returns>The data loaded.</returns>
-        Dictionary<string, List<object>> Load();
-
-        /// <summary>
-        /// Import an element to the collection of data.
-        /// </summary>
-        /// <typeparam name="T">The type of the element to impoert</typeparam>
-        /// <param name="pathToImport">The path containing the name of the file.</param>
-        /// <returns>A pair where the key is the entry in the data and the value is the value to add on this entry.</returns>
-        public KeyValuePair<string, T> Import<T>(string pathToImport)
-            where T : class;
-
-        /// <summary>
-        /// Export an element from the collection of data.
-        /// </summary>
-        /// <typeparam name="T">The type of the exported object.</typeparam>
-        /// <param name="obj">The object to export.</param>
-        /// <param name="pathToExport">The path containing the name of the file created.</param>
-        public void Export<T>(T obj, string pathToExport)
-            where T : class;
-    }
-}
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Model.Managers
+{
+    public interface IDataManager
+    {
+        void LoadData();
+        void ReloadData();
+        void SaveData();
+        void Import<T>(string pathOfTheFile) where T : class;
+        void Export<T>(T obj, string pathToExport) where T : class;
+    }
+}
diff --git a/MCTG/Model/Managers/IDataSerializer.cs b/MCTG/Model/Managers/IDataSerializer.cs
new file mode 100644
index 0000000..eba0cb6
--- /dev/null
+++ b/MCTG/Model/Managers/IDataSerializer.cs
@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Model
+{
+    /// <summary>
+    /// Interface that define the methods of a data serializer.
+    /// </summary>
+    public interface IDataSerializer
+    {
+        /// <summary>
+        /// Save all the data in a file.
+        /// </summary>
+        /// <param name="elements">The data to save.</param>
+        void Save(Dictionary<string, List<object>> elements);
+
+        /// <summary>
+        /// Load all the data from a file.
+        /// </summary>
+        /// <returns>The data loaded.</returns>
+        Dictionary<string, List<object>> Load();
+
+        /// <summary>
+        /// Import an element to the collection of data.
+        /// </summary>
+        /// <typeparam name="T">The type of the element to impoert</typeparam>
+        /// <param name="pathToImport">The path containing the name of the file.</param>
+        /// <returns>A pair where the key is the entry in the data and the value is the value to add on this entry.</returns>
+        public KeyValuePair<string, T> Import<T>(string pathToImport)
+            where T : class;
+
+        /// <summary>
+        /// Export an element from the collection of data.
+        /// </summary>
+        /// <typeparam name="T">The type of the exported object.</typeparam>
+        /// <param name="obj">The object to export.</param>
+        /// <param name="pathToExport">The path containing the name of the file created.</param>
+        public void Export<T>(T obj, string pathToExport)
+            where T : class;
+    }
+}
diff --git a/MCTG/Model/Managers/IRecipeManager.cs b/MCTG/Model/Managers/IRecipeManager.cs
new file mode 100644
index 0000000..f9d7e00
--- /dev/null
+++ b/MCTG/Model/Managers/IRecipeManager.cs
@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Model.Managers
+{
+    public interface IRecipeManager
+    {
+        RecipeCollection GetAllRecipes();
+        Recipe GetRecipeFromId(int id);
+        RecipeCollection GetRecipeByTitle(string title);
+        RecipeCollection GetRecipeByAuthor(string authorMail);
+        RecipeCollection GetRecipesByPriorityOrder(Priority priority);
+        bool AddRecipeToData(Recipe recipe);
+        bool ModifyRecipeInData(Recipe recipe);
+    }
+}
diff --git a/MCTG/Model/Managers/IUserManager.cs b/MCTG/Model/Managers/IUserManager.cs
new file mode 100644
index 0000000..d86a404
--- /dev/null
+++ b/MCTG/Model/Managers/IUserManager.cs
@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Model.Managers
+{
+    public interface IUserManager
+    {
+        ICollection<User> GetAllUsers();
+        User GetUserFromMail(string mail);
+        bool AddUserToData(User user);
+        bool ModifyUserInData(User user);
+        bool LogIn(string mail, string password);
+        bool LogOut();
+    }
+}
diff --git a/MCTG/Model/Managers/MasterManager.cs b/MCTG/Model/Managers/MasterManager.cs
index 6bad13f..cd3cc83 100644
--- a/MCTG/Model/Managers/MasterManager.cs
+++ b/MCTG/Model/Managers/MasterManager.cs
@@ -41,7 +41,7 @@ namespace Model.Managers
         /// Constructor of the MasterManager.
         /// </summary>
         /// <param name="dataManager">The serializer for the data.</param>
-        public MasterManager(IDataManager dataManager)
+        public MasterManager(IDataSerializer dataManager)
         {
             DataMgr = new DataManager(dataManager);
             CurrentConnectedUser = null;