diff --git a/Fastedit/Extensibility/CustomSyntaxHighlightLanguage.cs b/Fastedit/Extensibility/CustomSyntaxHighlightLanguage.cs
new file mode 100644
index 0000000..0a0c449
--- /dev/null
+++ b/Fastedit/Extensibility/CustomSyntaxHighlightLanguage.cs
@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using TextControlBoxNS;
+
+namespace Fastedit.Extensibility;
+
+/// <summary>
+/// Create a constructor without parameters and set values for all properties.
+/// </summary>
+public class CustomSyntaxHighlightLanguage : SyntaxHighlightLanguage, IExtensionInterface
+{
+    public CustomSyntaxHighlightLanguage() { }
+}
+
+public class CustomSyntaxHighlights : SyntaxHighlights
+{
+    public CustomSyntaxHighlights
+        (string pattern, string colorLight, string colorDark, bool bold = false, bool italic = false, bool underlined = false)
+        : base(pattern, colorLight, colorDark, bold, italic, underlined)
+    {
+    }
+}
\ No newline at end of file
diff --git a/Fastedit/Extensibility/IAboutPlugin.cs b/Fastedit/Extensibility/IAboutPlugin.cs
new file mode 100644
index 0000000..67ae543
--- /dev/null
+++ b/Fastedit/Extensibility/IAboutPlugin.cs
@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Extensibility;
+
+/// <summary>
+/// Implement this interface to give Ease Pass some information about your plugin. It is highly recommended to implement this interface a single time in every plugin.
+/// </summary>
+public interface IAboutPlugin : IExtensionInterface
+{
+    /// <summary>
+    /// Name of your plugin
+    /// </summary>
+    string PluginName { get; }
+    /// <summary>
+    /// Description of your plugin
+    /// </summary>
+    string PluginDescription { get; }
+    /// <summary>
+    /// Author of your plugin
+    /// </summary>
+    string PluginAuthor { get; }
+    /// <summary>
+    /// URL to the authors webpage
+    /// </summary>
+    string PluginAuthorURL { get; }
+    /// <summary>
+    /// URI to the icon of the plugin
+    /// </summary>
+    Uri PluginIcon { get; }
+}
\ No newline at end of file
diff --git a/Fastedit/Extensibility/IExtensionInterface.cs b/Fastedit/Extensibility/IExtensionInterface.cs
new file mode 100644
index 0000000..65008d8
--- /dev/null
+++ b/Fastedit/Extensibility/IExtensionInterface.cs
@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Extensibility;
+
+public interface IExtensionInterface
+{
+}
\ No newline at end of file
diff --git a/Fastedit/Extensibility/IExtensionSource.cs b/Fastedit/Extensibility/IExtensionSource.cs
new file mode 100644
index 0000000..d427dec
--- /dev/null
+++ b/Fastedit/Extensibility/IExtensionSource.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Extensibility;
+
+public interface IExtensionSource : IExtensionInterface
+{
+    /// <summary>
+    /// Name of the extension source.
+    /// </summary>
+    string SourceName { get; }
+    /// <summary>
+    /// Ease Pass will call this function to get the extension sources.
+    /// </summary>
+    /// <returns>The extension source and name.</returns>
+    (Uri Source, string Name)[] GetExtensionSources();
+}
\ No newline at end of file
diff --git a/Fastedit/Fastedit.csproj b/Fastedit/Fastedit.csproj
index 6dc70e5..84d9cc6 100644
--- a/Fastedit/Fastedit.csproj
+++ b/Fastedit/Fastedit.csproj
@@ -64,6 +64,9 @@
 	  <Generator>MSBuild:Compile</Generator>
 	</Page>
   </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Extensibility\" />
+  </ItemGroup>
 
   <!--
     Defining the "HasPackageAndPublishMenuAddedByProject" property here allows the Solution
diff --git a/Fastedit/Helper/ExtensionHelper.cs b/Fastedit/Helper/ExtensionHelper.cs
new file mode 100644
index 0000000..05e5bba
--- /dev/null
+++ b/Fastedit/Helper/ExtensionHelper.cs
@@ -0,0 +1,82 @@
+using Fastedit.Extensibility;
+using Fastedit.Models;
+using Microsoft.UI.Xaml;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Windows.Storage;
+
+namespace Fastedit.Helper;
+
+internal static class ExtensionHelper
+{
+    public static List<Extension> Extensions = new List<Extension>();
+
+    public static void Init()
+    {
+        Task.Run(new Action(async () =>
+        {
+            if (Directory.Exists(ApplicationData.Current.LocalFolder.Path + "\\extensions\\"))
+            {
+                if (File.Exists(ApplicationData.Current.LocalFolder.Path + "\\delete_extensions.dat"))
+                {
+                    foreach (string extensionID in File.ReadLines(ApplicationData.Current.LocalFolder.Path + "\\delete_extensions.dat"))
+                    {
+                        if (File.Exists(ApplicationData.Current.LocalFolder.Path + "\\extensions\\" + extensionID + ".dll"))
+                        {
+                            await (await (await ApplicationData.Current.LocalFolder.GetFolderAsync("extensions")).GetFileAsync(extensionID + ".dll")).DeleteAsync();
+                        }
+                    }
+                }
+
+                File.WriteAllText(ApplicationData.Current.LocalFolder.Path + "\\delete_extensions.dat", "");
+                string[] extensionPaths = Directory.GetFiles(ApplicationData.Current.LocalFolder.Path + "\\extensions\\");
+                Extensions.Clear();
+                for (int i = 0; i < extensionPaths.Length; i++)
+                {
+                    if (Path.GetExtension(extensionPaths[i]).ToLower() == ".dll")
+                    {
+                        Extensions.Add(new Extension(ReflectionHelper.GetAllExternalInstances(extensionPaths[i]), Path.GetFileNameWithoutExtension(extensionPaths[i])));
+                    }
+                }
+            }
+        }));
+    }
+
+    public static T[] GetAllClassesWithInterface<T>() where T : IExtensionInterface
+    {
+        List<T> result = new List<T>();
+        for (int i = 0; i < Extensions.Count; i++)
+        {
+            int length = Extensions[i].Interfaces.Length;
+            for (int j = 0; j < length; j++)
+            {
+                if (Extensions[i].Interfaces[j] is T t)
+                {
+                    result.Add(t);
+                }
+            }
+        }
+        return result.ToArray();
+    }
+
+    public static List<FetchedExtension> GetExtensionsFromSources()
+    {
+        List<FetchedExtension> res = new List<FetchedExtension>();
+        for (int i = 0; i < Extensions.Count; i++)
+        {
+            int length = Extensions[i].Interfaces.Length;
+            for (int j = 0; j < length; j++)
+            {
+                if (Extensions[i].Interfaces[j] is IExtensionSource source)
+                {
+                    res.AddRange(source.GetExtensionSources().Select((item) => { return new FetchedExtension(item.Source, item.Name, source.SourceName); }));
+                }
+            }
+        }
+        return res;
+    }
+}
\ No newline at end of file
diff --git a/Fastedit/Helper/ReflectionHelper.cs b/Fastedit/Helper/ReflectionHelper.cs
new file mode 100644
index 0000000..e8e417a
--- /dev/null
+++ b/Fastedit/Helper/ReflectionHelper.cs
@@ -0,0 +1,70 @@
+using Fastedit.Extensibility;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Helper;
+
+internal class ReflectionHelper
+{
+    public static IExtensionInterface[] GetAllExternalInstances(string path)
+    {
+        try
+        {
+            List<IExtensionInterface> res = new List<IExtensionInterface>();
+            Assembly plugin = Assembly.LoadFrom(path);
+            IEnumerable<System.Type> types = GetLoadableTypes(plugin);
+            foreach (System.Type t in types)
+            {
+                if (t.GetInterfaces().Contains(typeof(IExtensionInterface)))
+                {
+                    IExtensionInterface obj = (IExtensionInterface)GetInstanceOf(t);
+                    if (obj != null) res.Add(obj);
+                }
+            }
+            return res.ToArray();
+        }
+        catch
+        {
+            return new IExtensionInterface[0];
+        }
+    }
+
+    private static object GetInstanceOf(Type type)
+    {
+        try
+        {
+            ConstructorInfo[] cis = type.GetConstructors();
+            foreach (ConstructorInfo ci in cis)
+            {
+                if (ci.GetParameters().Length == 0)
+                {
+                    return type.Assembly.CreateInstance(type.FullName);
+                }
+            }
+        }
+        catch { }
+        return null;
+    }
+
+    private static IEnumerable<Type> GetLoadableTypes(Assembly assembly)
+    {
+        if (assembly == null) throw new ArgumentNullException(nameof(assembly));
+        try
+        {
+            List<Type> types = new List<Type>();
+            foreach (TypeInfo ti in assembly.DefinedTypes)
+            {
+                types.Add(ti.AsType());
+            }
+            return types;
+        }
+        catch (ReflectionTypeLoadException e)
+        {
+            return e.Types.Where(t => t != null);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Fastedit/MainWindow.xaml.cs b/Fastedit/MainWindow.xaml.cs
index 03b512e..958e666 100644
--- a/Fastedit/MainWindow.xaml.cs
+++ b/Fastedit/MainWindow.xaml.cs
@@ -1,4 +1,5 @@
 using Fastedit.Core;
+using Fastedit.Helper;
 using Microsoft.UI.Dispatching;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
@@ -37,6 +38,8 @@ public MainWindow()
 
             this.Title = "Fastedit";
             this.AppWindow.SetIcon(Path.Combine(Package.Current.InstalledLocation.Path, "Assets\\AppIcon\\Icon.ico"));
+
+            ExtensionHelper.Init();
         }
 
         private void MainWindow_Closed(object sender, WindowEventArgs args)
diff --git a/Fastedit/Models/DummyExtensionPage.cs b/Fastedit/Models/DummyExtensionPage.cs
new file mode 100644
index 0000000..2cb21ad
--- /dev/null
+++ b/Fastedit/Models/DummyExtensionPage.cs
@@ -0,0 +1,21 @@
+using Fastedit.Extensibility;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Models;
+
+internal class DummyAboutExtensionPage : IAboutPlugin
+{
+    public string PluginName => "Unknown name";
+
+    public string PluginDescription => "Unknown description";
+
+    public string PluginAuthor => "Unknown author";
+
+    public string PluginAuthorURL => "";
+
+    public Uri PluginIcon => new Uri("ms-appx:///Assets/AppIcon/Icon.png");
+}
diff --git a/Fastedit/Models/Extension.cs b/Fastedit/Models/Extension.cs
new file mode 100644
index 0000000..262a8b7
--- /dev/null
+++ b/Fastedit/Models/Extension.cs
@@ -0,0 +1,87 @@
+using Fastedit.Extensibility;
+using Microsoft.UI.Xaml.Media.Imaging;
+using Microsoft.UI.Xaml.Media;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Models;
+
+internal class Extension
+{
+    public IExtensionInterface[] Interfaces;
+
+    public IAboutPlugin AboutPlugin = null;
+
+    public ImageSource IconSource
+    {
+        get
+        {
+            if (AboutPlugin != null) return new BitmapImage(AboutPlugin.PluginIcon);
+            return null;
+        }
+    }
+
+    public string ID = "";
+
+    public Extension(IExtensionInterface[] interfaces, string id)
+    {
+        Interfaces = interfaces;
+        int length = interfaces.Length;
+        for (int i = 0; i < length; i++)
+        {
+            if (interfaces[i] is IAboutPlugin plugin)
+            {
+                AboutPlugin = plugin;
+            }
+        }
+        if (AboutPlugin == null)
+        {
+            AboutPlugin = new DummyAboutExtensionPage();
+        }
+        ID = id;
+    }
+
+    public override string ToString()
+    {
+        return ToString(true);
+    }
+
+    public string ToString(bool headline)
+    {
+        List<string> items = new List<string>();
+        int length = Interfaces.Length;
+        for (int i = 0; i < length; i++)
+        {
+            if (Interfaces[i] is CustomSyntaxHighlightLanguage) items.Add("• add custom syntax highlighting");
+            if (Interfaces[i] is IExtensionSource) items.Add("• add extensions to the store");
+            // fill up with other interfaces
+        }
+        List<string> itemsFinal = new List<string>();
+        for (int i = 0; i < items.Count; i++)
+        {
+            if (!itemsFinal.Contains(items[i]))
+                itemsFinal.Add(items[i]);
+        }
+
+        StringBuilder sb = new StringBuilder();
+        if (headline)
+        {
+            sb.AppendLine("Authorizations requested by plugin:");
+        }
+
+        for (int i = 0; i < itemsFinal.Count; i++)
+        {
+            sb.AppendLine(itemsFinal[i]);
+        }
+
+        return sb.ToString();
+    }
+
+    public string GetPluginInterfaceGUID(IExtensionInterface extInterface)
+    {
+        return extInterface.GetType().GUID.ToString();
+    }
+}
diff --git a/Fastedit/Models/FetchedExtension.cs b/Fastedit/Models/FetchedExtension.cs
new file mode 100644
index 0000000..d2507cc
--- /dev/null
+++ b/Fastedit/Models/FetchedExtension.cs
@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Fastedit.Models;
+
+internal class FetchedExtension
+{
+    public Uri URL { get; set; }
+    public string Name { get; set; }
+    public string Source { get; set; }
+
+    public FetchedExtension(Uri url, string name, string source)
+    {
+        this.URL = url;
+        this.Name = name;
+        Source = source;
+    }
+}
\ No newline at end of file
diff --git a/Fastedit/Views/MainPage.xaml.cs b/Fastedit/Views/MainPage.xaml.cs
index 42e91c7..f847704 100644
--- a/Fastedit/Views/MainPage.xaml.cs
+++ b/Fastedit/Views/MainPage.xaml.cs
@@ -12,6 +12,8 @@
 using TextControlBoxNS;
 using Fastedit.Core.Settings;
 using Fastedit.Core.Tab;
+using System.Collections.Generic;
+using Fastedit.Extensibility;
 
 namespace Fastedit;
 
@@ -564,6 +566,15 @@ private void CreateMenubarFromLanguage()
             RunCommandWindowItem_Designs.Items.Add(runCommandWindowItem);
         }
     }
+    private CustomSyntaxHighlightLanguage[] LoadHighlightersFromExtensions()
+    {
+        List<CustomSyntaxHighlightLanguage> hightlighters = new List<CustomSyntaxHighlightLanguage>();
+        for (int i = 0; i < ExtensionHelper.Extensions.Count; i++)
+            for (int j = 0; j < ExtensionHelper.Extensions[i].Interfaces.Length; j++)
+                if (ExtensionHelper.Extensions[i].Interfaces[j] is CustomSyntaxHighlightLanguage c)
+                    hightlighters.Add(c);
+        return hightlighters.ToArray();
+    }
 
     private void RunCommandWindow_ChangeDesign_Click(object sender, RoutedEventArgs e)
     {