diff --git a/DotTiled.Tests/Assert/AssertObject.cs b/DotTiled.Tests/Assert/AssertObject.cs
index 68d74eb..3b08744 100644
--- a/DotTiled.Tests/Assert/AssertObject.cs
+++ b/DotTiled.Tests/Assert/AssertObject.cs
@@ -17,7 +17,7 @@ public static partial class DotTiledAssert
     Assert.Equal(expected.Visible, actual.Visible);
     Assert.Equal(expected.Template, actual.Template);
 
-    AssertProperties(actual.Properties, expected.Properties);
+    AssertProperties(expected.Properties, actual.Properties);
     AssertObject((dynamic)expected, (dynamic)actual);
   }
 
diff --git a/DotTiled.Tests/Assert/AssertProperties.cs b/DotTiled.Tests/Assert/AssertProperties.cs
index d0a8269..afd28c2 100644
--- a/DotTiled.Tests/Assert/AssertProperties.cs
+++ b/DotTiled.Tests/Assert/AssertProperties.cs
@@ -19,51 +19,51 @@ public static partial class DotTiledAssert
     }
   }
 
-  private static void AssertProperty(IProperty actual, IProperty expected)
+  private static void AssertProperty(IProperty expected, IProperty actual)
   {
     Assert.Equal(expected.Type, actual.Type);
     Assert.Equal(expected.Name, actual.Name);
     AssertProperties((dynamic)actual, (dynamic)expected);
   }
 
-  private static void AssertProperty(StringProperty actual, StringProperty expected)
+  private static void AssertProperty(StringProperty expected, StringProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(IntProperty actual, IntProperty expected)
+  private static void AssertProperty(IntProperty expected, IntProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(FloatProperty actual, FloatProperty expected)
+  private static void AssertProperty(FloatProperty expected, FloatProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(BoolProperty actual, BoolProperty expected)
+  private static void AssertProperty(BoolProperty expected, BoolProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(ColorProperty actual, ColorProperty expected)
+  private static void AssertProperty(ColorProperty expected, ColorProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(FileProperty actual, FileProperty expected)
+  private static void AssertProperty(FileProperty expected, FileProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(ObjectProperty actual, ObjectProperty expected)
+  private static void AssertProperty(ObjectProperty expected, ObjectProperty actual)
   {
     Assert.Equal(expected.Value, actual.Value);
   }
 
-  private static void AssertProperty(ClassProperty actual, ClassProperty expected)
+  private static void AssertProperty(ClassProperty expected, ClassProperty actual)
   {
     Assert.Equal(expected.PropertyType, actual.PropertyType);
-    AssertProperties(actual.Properties, expected.Properties);
+    AssertProperties(expected.Properties, actual.Properties);
   }
 }
diff --git a/DotTiled.Tests/Serialization/TestData/Map/map-with-object-template.cs b/DotTiled.Tests/Serialization/TestData/Map/map-with-object-template.cs
index 26ddde8..1f9cb1c 100644
--- a/DotTiled.Tests/Serialization/TestData/Map/map-with-object-template.cs
+++ b/DotTiled.Tests/Serialization/TestData/Map/map-with-object-template.cs
@@ -2,7 +2,7 @@ namespace DotTiled.Tests;
 
 public partial class TestData
 {
-  public static Map MapWithObjectTemplate() => new Map
+  public static Map MapWithObjectTemplate(string templateExtension) => new Map
   {
     Version = "1.10",
     TiledVersion = "1.11.0",
@@ -49,7 +49,7 @@ public partial class TestData
           new RectangleObject
           {
             ID = 1,
-            Template = "map-with-object-template.tx",
+            Template = $"map-with-object-template.{templateExtension}",
             Name = "Thingy 2",
             X = 94.5749f,
             Y = 33.6842f,
@@ -73,7 +73,7 @@ public partial class TestData
           new RectangleObject
           {
             ID = 2,
-            Template = "map-with-object-template.tx",
+            Template = $"map-with-object-template.{templateExtension}",
             Name = "Thingy",
             X = 29.7976f,
             Y = 33.8693f,
@@ -97,7 +97,7 @@ public partial class TestData
           new RectangleObject
           {
             ID = 3,
-            Template = "map-with-object-template.tx",
+            Template = $"map-with-object-template.{templateExtension}",
             Name = "Thingy 3",
             X = 5,
             Y = 5,
@@ -112,7 +112,7 @@ public partial class TestData
                 PropertyType = "TestClass",
                 Properties = new Dictionary<string, IProperty>
                 {
-                  ["Amount"] = new FloatProperty { Name = "Amount", Value = 4.2f },
+                  ["Amount"] = new FloatProperty { Name = "Amount", Value = 0.0f },
                   ["Name"] = new StringProperty { Name = "Name", Value = "I am here 3" }
                 }
               }
diff --git a/DotTiled.Tests/Serialization/TestData/map-with-object-template-propertytypes.json b/DotTiled.Tests/Serialization/TestData/map-with-object-template-propertytypes.json
new file mode 100644
index 0000000..3505dce
--- /dev/null
+++ b/DotTiled.Tests/Serialization/TestData/map-with-object-template-propertytypes.json
@@ -0,0 +1,24 @@
+[
+    {
+        "color": "#ffa0a0a4",
+        "drawFill": true,
+        "id": 1,
+        "members": [
+            {
+                "name": "Amount",
+                "type": "float",
+                "value": 0
+            },
+            {
+                "name": "Name",
+                "type": "string",
+                "value": ""
+            }
+        ],
+        "name": "TestClass",
+        "type": "class",
+        "useAs": [
+            "property"
+        ]
+    }
+]
diff --git a/DotTiled.Tests/Serialization/TestData/propertytypes-2.json b/DotTiled.Tests/Serialization/TestData/propertytypes-2.json
new file mode 100644
index 0000000..e21cf83
--- /dev/null
+++ b/DotTiled.Tests/Serialization/TestData/propertytypes-2.json
@@ -0,0 +1,103 @@
+[
+    {
+        "id": 4,
+        "name": "Enum0String",
+        "storageType": "string",
+        "type": "enum",
+        "values": [
+            "Enum0_1",
+            "Enum0_2",
+            "Enum0_3"
+        ],
+        "valuesAsFlags": false
+    },
+    {
+        "id": 5,
+        "name": "Enum1Num",
+        "storageType": "int",
+        "type": "enum",
+        "values": [
+            "Enum1Num_1",
+            "Enum1Num_2",
+            "Enum1Num_3",
+            "Enum1Num_4"
+        ],
+        "valuesAsFlags": false
+    },
+    {
+        "id": 6,
+        "name": "Enum2StringFlags",
+        "storageType": "string",
+        "type": "enum",
+        "values": [
+            "Enum2StringFlags_1",
+            "Enum2StringFlags_2",
+            "Enum2StringFlags_3",
+            "Enum2StringFlags_4"
+        ],
+        "valuesAsFlags": true
+    },
+    {
+        "id": 7,
+        "name": "Enum3NumFlags",
+        "storageType": "int",
+        "type": "enum",
+        "values": [
+            "Enum3NumFlags_1",
+            "Enum3NumFlags_2",
+            "Enum3NumFlags_3",
+            "Enum3NumFlags_4",
+            "Enum3NumFlags_5"
+        ],
+        "valuesAsFlags": true
+    },
+    {
+        "color": "#ffa0a0a4",
+        "drawFill": true,
+        "id": 2,
+        "members": [
+            {
+                "name": "Yep",
+                "propertyType": "TestClass",
+                "type": "class",
+                "value": {
+                }
+            }
+        ],
+        "name": "Test",
+        "type": "class",
+        "useAs": [
+            "property",
+            "map",
+            "layer",
+            "object",
+            "tile",
+            "tileset",
+            "wangcolor",
+            "wangset",
+            "project"
+        ]
+    },
+    {
+        "color": "#ffa0a0a4",
+        "drawFill": true,
+        "id": 1,
+        "members": [
+            {
+                "name": "Amount",
+                "type": "float",
+                "value": 0
+            },
+            {
+                "name": "Name",
+                "type": "string",
+                "value": ""
+            }
+        ],
+        "name": "TestClass",
+        "type": "class",
+        "useAs": [
+            "property"
+        ]
+    }
+]
diff --git a/DotTiled.Tests/Serialization/Tmj/TmjMapReaderTests.cs b/DotTiled.Tests/Serialization/Tmj/TmjMapReaderTests.cs
index 605cda9..7e220a9 100644
--- a/DotTiled.Tests/Serialization/Tmj/TmjMapReaderTests.cs
+++ b/DotTiled.Tests/Serialization/Tmj/TmjMapReaderTests.cs
@@ -20,17 +20,13 @@ public partial class TmjMapReaderTests
     var json = TestData.GetRawStringFor(testDataFile);
     static Template ResolveTemplate(string source)
     {
-      var templateJson = TestData.GetRawStringFor($"Serialization.TestData.Template.{source}");
-      //var templateReader = new TmjTemplateReader(templateJson, ResolveTemplate);
-      return null;
+      throw new NotSupportedException("External templates are not supported in this test.");
     }
     static Tileset ResolveTileset(string source)
     {
-      var tilesetJson = TestData.GetXmlReaderFor($"Serialization.TestData.Tileset.{source}");
-      //var tilesetReader = new TmjTilesetReader(tilesetJson, ResolveTileset, ResolveTemplate);
-      return null;
+      throw new NotSupportedException("External tilesets are not supported in this test.");
     }
-    using var mapReader = new TmjMapReader(json, ResolveTileset, ResolveTemplate);
+    using var mapReader = new TmjMapReader(json, ResolveTileset, ResolveTemplate, []);
 
     // Act
     var map = mapReader.ReadMap();
@@ -42,7 +38,7 @@ public partial class TmjMapReaderTests
 
   public static IEnumerable<object[]> DeserializeMap_ValidTmjExternalTilesetsAndTemplates_ReturnsMapThatEqualsExpected_Data =>
   [
-    ["Serialization.TestData.Map.map-with-object-template.tmj", TestData.MapWithObjectTemplate()],
+    ["Serialization.TestData.Map.map-with-object-template.tmj", TestData.MapWithObjectTemplate("tj")],
     ["Serialization.TestData.Map.map-with-group.tmj", TestData.MapWithGroup()],
   ];
 
@@ -51,20 +47,55 @@ public partial class TmjMapReaderTests
   public void TmxMapReaderReadMap_ValidTmjExternalTilesetsAndTemplates_ReturnsMapThatEqualsExpected(string testDataFile, Map expectedMap)
   {
     // Arrange
+    CustomTypeDefinition[] customTypeDefinitions = [
+      new CustomClassDefinition
+      {
+        Name = "TestClass",
+        ID = 1,
+        UseAs = CustomClassUseAs.Property,
+        Members = [
+          new StringProperty
+          {
+            Name = "Name",
+            Value = ""
+          },
+          new FloatProperty
+          {
+            Name = "Amount",
+            Value = 0f
+          }
+        ]
+      },
+      new CustomClassDefinition
+      {
+        Name = "Test",
+        ID = 2,
+        UseAs = CustomClassUseAs.All,
+        Members = [
+          new ClassProperty
+          {
+            Name = "Yep",
+            PropertyType = "TestClass",
+            Properties = []
+          }
+        ]
+      }
+    ];
+
     var json = TestData.GetRawStringFor(testDataFile);
-    static Template ResolveTemplate(string source)
+    Template ResolveTemplate(string source)
     {
       var templateJson = TestData.GetRawStringFor($"Serialization.TestData.Template.{source}");
-      //var templateReader = new TmjTemplateReader(templateJson, ResolveTemplate);
-      return null;
+      using var templateReader = new TjTemplateReader(templateJson, ResolveTileset, ResolveTemplate, customTypeDefinitions);
+      return templateReader.ReadTemplate();
     }
-    static Tileset ResolveTileset(string source)
+    Tileset ResolveTileset(string source)
     {
-      var tilesetJson = TestData.GetXmlReaderFor($"Serialization.TestData.Tileset.{source}");
-      //var tilesetReader = new TmjTilesetReader(tilesetJson, ResolveTileset, ResolveTemplate);
-      return null;
+      var tilesetJson = TestData.GetRawStringFor($"Serialization.TestData.Tileset.{source}");
+      using var tilesetReader = new TsjTilesetReader(tilesetJson, ResolveTemplate, customTypeDefinitions);
+      return tilesetReader.ReadTileset();
     }
-    using var mapReader = new TmjMapReader(json, ResolveTileset, ResolveTemplate);
+    using var mapReader = new TmjMapReader(json, ResolveTileset, ResolveTemplate, customTypeDefinitions);
 
     // Act
     var map = mapReader.ReadMap();
diff --git a/DotTiled.Tests/Serialization/Tmx/TmxMapReaderTests.cs b/DotTiled.Tests/Serialization/Tmx/TmxMapReaderTests.cs
index 7a1fc66..7c25d1b 100644
--- a/DotTiled.Tests/Serialization/Tmx/TmxMapReaderTests.cs
+++ b/DotTiled.Tests/Serialization/Tmx/TmxMapReaderTests.cs
@@ -116,7 +116,7 @@ public partial class TmxMapReaderTests
 
   public static IEnumerable<object[]> DeserializeMap_ValidXmlExternalTilesetsAndTemplates_ReturnsMapThatEqualsExpected_Data =>
   [
-    ["Serialization.TestData.Map.map-with-object-template.tmx", TestData.MapWithObjectTemplate()],
+    ["Serialization.TestData.Map.map-with-object-template.tmx", TestData.MapWithObjectTemplate("tx")],
     ["Serialization.TestData.Map.map-with-group.tmx", TestData.MapWithGroup()],
   ];
 
diff --git a/DotTiled/Model/IProperty.cs b/DotTiled/Model/IProperty.cs
index 9558ee2..ae522f2 100644
--- a/DotTiled/Model/IProperty.cs
+++ b/DotTiled/Model/IProperty.cs
@@ -1,4 +1,6 @@
+using System;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace DotTiled;
 
@@ -18,6 +20,8 @@ public interface IProperty
 {
   public string Name { get; set; }
   public PropertyType Type { get; }
+
+  IProperty Clone();
 }
 
 public class StringProperty : IProperty
@@ -25,6 +29,12 @@ public class StringProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.String;
   public required string Value { get; set; }
+
+  public IProperty Clone() => new StringProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class IntProperty : IProperty
@@ -32,6 +42,12 @@ public class IntProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.Int;
   public required int Value { get; set; }
+
+  public IProperty Clone() => new IntProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class FloatProperty : IProperty
@@ -39,6 +55,12 @@ public class FloatProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.Float;
   public required float Value { get; set; }
+
+  public IProperty Clone() => new FloatProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class BoolProperty : IProperty
@@ -46,6 +68,12 @@ public class BoolProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.Bool;
   public required bool Value { get; set; }
+
+  public IProperty Clone() => new BoolProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class ColorProperty : IProperty
@@ -53,6 +81,12 @@ public class ColorProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.Color;
   public required Color Value { get; set; }
+
+  public IProperty Clone() => new ColorProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class FileProperty : IProperty
@@ -60,6 +94,12 @@ public class FileProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.File;
   public required string Value { get; set; }
+
+  public IProperty Clone() => new FileProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class ObjectProperty : IProperty
@@ -67,6 +107,12 @@ public class ObjectProperty : IProperty
   public required string Name { get; set; }
   public PropertyType Type => PropertyType.Object;
   public required uint Value { get; set; }
+
+  public IProperty Clone() => new ObjectProperty
+  {
+    Name = Name,
+    Value = Value
+  };
 }
 
 public class ClassProperty : IProperty
@@ -75,4 +121,53 @@ public class ClassProperty : IProperty
   public PropertyType Type => DotTiled.PropertyType.Class;
   public required string PropertyType { get; set; }
   public required Dictionary<string, IProperty> Properties { get; set; }
+
+  public IProperty Clone() => new ClassProperty
+  {
+    Name = Name,
+    PropertyType = PropertyType,
+    Properties = Properties.ToDictionary(p => p.Key, p => p.Value.Clone())
+  };
+}
+
+public abstract class CustomTypeDefinition
+{
+  public uint ID { get; set; }
+  public string Name { get; set; } = "";
+}
+
+[Flags]
+public enum CustomClassUseAs
+{
+  Property,
+  Map,
+  Layer,
+  Object,
+  Tile,
+  Tileset,
+  WangColor,
+  Wangset,
+  Project,
+  All = Property | Map | Layer | Object | Tile | Tileset | WangColor | Wangset | Project
+}
+
+public class CustomClassDefinition : CustomTypeDefinition
+{
+  public Color Color { get; set; }
+  public bool DrawFill { get; set; }
+  public CustomClassUseAs UseAs { get; set; }
+  public List<IProperty> Members { get; set; }
+}
+
+public enum CustomEnumStorageType
+{
+  Int,
+  String
+}
+
+public class CustomEnumDefinition : CustomTypeDefinition
+{
+  public CustomEnumStorageType StorageType { get; set; }
+  public List<string> Values { get; set; } = [];
+  public bool ValueAsFlags { get; set; }
 }
diff --git a/DotTiled/Serialization/Tmj/TjTemplateReader.cs b/DotTiled/Serialization/Tmj/TjTemplateReader.cs
new file mode 100644
index 0000000..0dc1dd8
--- /dev/null
+++ b/DotTiled/Serialization/Tmj/TjTemplateReader.cs
@@ -0,0 +1,64 @@
+using System;
+using System.Collections.Generic;
+
+namespace DotTiled;
+
+public class TjTemplateReader : ITemplateReader
+{
+  // External resolvers
+  private readonly Func<string, Tileset> _externalTilesetResolver;
+  private readonly Func<string, Template> _externalTemplateResolver;
+
+  private readonly string _jsonString;
+  private bool disposedValue;
+
+  private readonly IReadOnlyCollection<CustomTypeDefinition> _customTypeDefinitions;
+
+  public TjTemplateReader(
+    string jsonString,
+    Func<string, Tileset> externalTilesetResolver,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    _jsonString = jsonString ?? throw new ArgumentNullException(nameof(jsonString));
+    _externalTilesetResolver = externalTilesetResolver ?? throw new ArgumentNullException(nameof(externalTilesetResolver));
+    _externalTemplateResolver = externalTemplateResolver ?? throw new ArgumentNullException(nameof(externalTemplateResolver));
+    _customTypeDefinitions = customTypeDefinitions ?? throw new ArgumentNullException(nameof(customTypeDefinitions));
+  }
+
+  public Template ReadTemplate()
+  {
+    var jsonDoc = System.Text.Json.JsonDocument.Parse(_jsonString);
+    var rootElement = jsonDoc.RootElement;
+    return Tmj.ReadTemplate(rootElement, _externalTilesetResolver, _externalTemplateResolver, _customTypeDefinitions);
+  }
+
+  protected virtual void Dispose(bool disposing)
+  {
+    if (!disposedValue)
+    {
+      if (disposing)
+      {
+        // TODO: dispose managed state (managed objects)
+      }
+
+      // TODO: free unmanaged resources (unmanaged objects) and override finalizer
+      // TODO: set large fields to null
+      disposedValue = true;
+    }
+  }
+
+  // // TODO: override finalizer only if 'Dispose(bool disposing)' has code to free unmanaged resources
+  // ~TjTemplateReader()
+  // {
+  //     // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+  //     Dispose(disposing: false);
+  // }
+
+  public void Dispose()
+  {
+    // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+    Dispose(disposing: true);
+    GC.SuppressFinalize(this);
+  }
+}
diff --git a/DotTiled/Serialization/Tmj/Tmj.Layer.cs b/DotTiled/Serialization/Tmj/Tmj.Layer.cs
index 7e8685e..33d87e7 100644
--- a/DotTiled/Serialization/Tmj/Tmj.Layer.cs
+++ b/DotTiled/Serialization/Tmj/Tmj.Layer.cs
@@ -4,27 +4,33 @@ using System.Globalization;
 using System.IO;
 using System.IO.Compression;
 using System.Linq;
+using System.Numerics;
 using System.Text.Json;
 
 namespace DotTiled;
 
 internal partial class Tmj
 {
-  internal static BaseLayer ReadLayer(JsonElement element)
+  internal static BaseLayer ReadLayer(
+    JsonElement element,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
   {
     var type = element.GetRequiredProperty<string>("type");
 
     return type switch
     {
-      "tilelayer" => ReadTileLayer(element),
-      // "objectgroup" => ReadObjectGroup(element),
+      "tilelayer" => ReadTileLayer(element, customTypeDefinitions),
+      "objectgroup" => ReadObjectLayer(element, externalTemplateResolver, customTypeDefinitions),
       // "imagelayer" => ReadImageLayer(element),
-      // "group" => ReadGroup(element),
+      "group" => ReadGroup(element, externalTemplateResolver, customTypeDefinitions),
       _ => throw new JsonException($"Unsupported layer type '{type}'.")
     };
   }
 
-  internal static TileLayer ReadTileLayer(JsonElement element)
+  internal static TileLayer ReadTileLayer(
+    JsonElement element,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
   {
     var compression = element.GetOptionalPropertyParseable<DataCompression?>("compression", s => s switch
     {
@@ -50,7 +56,7 @@ internal partial class Tmj
     var opacity = element.GetOptionalProperty<float>("opacity", 1.0f);
     var parallaxx = element.GetOptionalProperty<float>("parallaxx", 1.0f);
     var parallaxy = element.GetOptionalProperty<float>("parallaxy", 1.0f);
-    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", e => ReadProperties(e), null);
+    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", e => ReadProperties(e, customTypeDefinitions), null);
     var repeatX = element.GetOptionalProperty<bool>("repeatx", false);
     var repeatY = element.GetOptionalProperty<bool>("repeaty", false);
     var startX = element.GetOptionalProperty<int>("startx", 0);
@@ -85,4 +91,276 @@ internal partial class Tmj
       Data = data ?? chunks
     };
   }
+
+  internal static Group ReadGroup(
+    JsonElement element,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    var id = element.GetRequiredProperty<uint>("id");
+    var name = element.GetRequiredProperty<string>("name");
+    var @class = element.GetOptionalProperty<string>("class", "");
+    var opacity = element.GetOptionalProperty<float>("opacity", 1.0f);
+    var visible = element.GetOptionalProperty<bool>("visible", true);
+    var tintColor = element.GetOptionalPropertyParseable<Color?>("tintcolor", s => Color.Parse(s, CultureInfo.InvariantCulture), null);
+    var offsetX = element.GetOptionalProperty<float>("offsetx", 0.0f);
+    var offsetY = element.GetOptionalProperty<float>("offsety", 0.0f);
+    var parallaxX = element.GetOptionalProperty<float>("parallaxx", 1.0f);
+    var parallaxY = element.GetOptionalProperty<float>("parallaxy", 1.0f);
+    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", e => ReadProperties(e, customTypeDefinitions), null);
+    var layers = element.GetOptionalPropertyCustom<List<BaseLayer>>("layers", e => e.GetValueAsList<BaseLayer>(el => ReadLayer(el, externalTemplateResolver, customTypeDefinitions)), []);
+
+    return new Group
+    {
+      ID = id,
+      Name = name,
+      Class = @class,
+      Opacity = opacity,
+      Visible = visible,
+      TintColor = tintColor,
+      OffsetX = offsetX,
+      OffsetY = offsetY,
+      ParallaxX = parallaxX,
+      ParallaxY = parallaxY,
+      Properties = properties,
+      Layers = layers
+    };
+  }
+
+  internal static ObjectLayer ReadObjectLayer(
+    JsonElement element,
+    Func<string, Template> externalTemplateResolver,
+     IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    var id = element.GetRequiredProperty<uint>("id");
+    var name = element.GetRequiredProperty<string>("name");
+    var @class = element.GetOptionalProperty<string>("class", "");
+    var opacity = element.GetOptionalProperty<float>("opacity", 1.0f);
+    var visible = element.GetOptionalProperty<bool>("visible", true);
+    var tintColor = element.GetOptionalPropertyParseable<Color?>("tintcolor", s => Color.Parse(s, CultureInfo.InvariantCulture), null);
+    var offsetX = element.GetOptionalProperty<float>("offsetx", 0.0f);
+    var offsetY = element.GetOptionalProperty<float>("offsety", 0.0f);
+    var parallaxX = element.GetOptionalProperty<float>("parallaxx", 1.0f);
+    var parallaxY = element.GetOptionalProperty<float>("parallaxy", 1.0f);
+    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", e => ReadProperties(e, customTypeDefinitions), null);
+
+    var x = element.GetOptionalProperty<uint>("x", 0);
+    var y = element.GetOptionalProperty<uint>("y", 0);
+    var width = element.GetOptionalProperty<uint?>("width", null);
+    var height = element.GetOptionalProperty<uint?>("height", null);
+    var color = element.GetOptionalPropertyParseable<Color?>("color", s => Color.Parse(s, CultureInfo.InvariantCulture), null);
+    var drawOrder = element.GetOptionalPropertyParseable<DrawOrder>("draworder", s => s switch
+    {
+      "topdown" => DrawOrder.TopDown,
+      "index" => DrawOrder.Index,
+      _ => throw new JsonException($"Unknown draw order '{s}'.")
+    }, DrawOrder.TopDown);
+
+    var objects = element.GetOptionalPropertyCustom<List<Object>>("objects", e => e.GetValueAsList<Object>(el => ReadObject(el, externalTemplateResolver, customTypeDefinitions)), []);
+
+    return new ObjectLayer
+    {
+      ID = id,
+      Name = name,
+      Class = @class,
+      Opacity = opacity,
+      Visible = visible,
+      TintColor = tintColor,
+      OffsetX = offsetX,
+      OffsetY = offsetY,
+      ParallaxX = parallaxX,
+      ParallaxY = parallaxY,
+      Properties = properties,
+      X = x,
+      Y = y,
+      Width = width,
+      Height = height,
+      Color = color,
+      DrawOrder = drawOrder,
+      Objects = objects
+    };
+  }
+
+  internal static Object ReadObject(
+    JsonElement element,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    uint? idDefault = null;
+    string nameDefault = "";
+    string typeDefault = "";
+    float xDefault = 0f;
+    float yDefault = 0f;
+    float widthDefault = 0f;
+    float heightDefault = 0f;
+    float rotationDefault = 0f;
+    uint? gidDefault = null;
+    bool visibleDefault = true;
+    bool ellipseDefault = false;
+    bool pointDefault = false;
+    List<Vector2>? polygonDefault = null;
+    List<Vector2>? polylineDefault = null;
+    Dictionary<string, IProperty>? propertiesDefault = null;
+
+    var template = element.GetOptionalProperty<string?>("template", null);
+    if (template is not null)
+    {
+      var resolvedTemplate = externalTemplateResolver(template);
+      var templObj = resolvedTemplate.Object;
+
+      idDefault = templObj.ID;
+      nameDefault = templObj.Name;
+      typeDefault = templObj.Type;
+      xDefault = templObj.X;
+      yDefault = templObj.Y;
+      widthDefault = templObj.Width;
+      heightDefault = templObj.Height;
+      rotationDefault = templObj.Rotation;
+      gidDefault = templObj.GID;
+      visibleDefault = templObj.Visible;
+      propertiesDefault = templObj.Properties;
+      ellipseDefault = templObj is EllipseObject;
+      pointDefault = templObj is PointObject;
+      polygonDefault = (templObj is PolygonObject polygonObj) ? polygonObj.Points : null;
+      polylineDefault = (templObj is PolylineObject polylineObj) ? polylineObj.Points : null;
+    }
+
+    var ellipse = element.GetOptionalProperty<bool>("ellipse", ellipseDefault);
+    var gid = element.GetOptionalProperty<uint?>("gid", gidDefault);
+    var height = element.GetOptionalProperty<float>("height", heightDefault);
+    var id = element.GetOptionalProperty<uint?>("id", idDefault);
+    var name = element.GetOptionalProperty<string>("name", nameDefault);
+    var point = element.GetOptionalProperty<bool>("point", pointDefault);
+    var polygon = element.GetOptionalPropertyCustom<List<Vector2>?>("polygon", e => ReadPoints(e), polygonDefault);
+    var polyline = element.GetOptionalPropertyCustom<List<Vector2>?>("polyline", e => ReadPoints(e), polylineDefault);
+    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", e => ReadProperties(e, customTypeDefinitions), propertiesDefault);
+    var rotation = element.GetOptionalProperty<float>("rotation", rotationDefault);
+    // var text
+    var type = element.GetOptionalProperty<string>("type", typeDefault);
+    var visible = element.GetOptionalProperty<bool>("visible", visibleDefault);
+    var width = element.GetOptionalProperty<float>("width", widthDefault);
+    var x = element.GetOptionalProperty<float>("x", xDefault);
+    var y = element.GetOptionalProperty<float>("y", yDefault);
+
+    if (ellipse)
+    {
+      return new EllipseObject
+      {
+        ID = id,
+        Name = name,
+        Type = type,
+        X = x,
+        Y = y,
+        Width = width,
+        Height = height,
+        Rotation = rotation,
+        GID = gid,
+        Visible = visible,
+        Template = template,
+        Properties = properties
+      };
+    }
+
+    if (point)
+    {
+      return new PointObject
+      {
+        ID = id,
+        Name = name,
+        Type = type,
+        X = x,
+        Y = y,
+        Width = width,
+        Height = height,
+        Rotation = rotation,
+        GID = gid,
+        Visible = visible,
+        Template = template,
+        Properties = properties
+      };
+    }
+
+    if (polygon is not null)
+    {
+      return new PolygonObject
+      {
+        ID = id,
+        Name = name,
+        Type = type,
+        X = x,
+        Y = y,
+        Width = width,
+        Height = height,
+        Rotation = rotation,
+        GID = gid,
+        Visible = visible,
+        Template = template,
+        Properties = properties,
+        Points = polygon
+      };
+    }
+
+    if (polyline is not null)
+    {
+      return new PolylineObject
+      {
+        ID = id,
+        Name = name,
+        Type = type,
+        X = x,
+        Y = y,
+        Width = width,
+        Height = height,
+        Rotation = rotation,
+        GID = gid,
+        Visible = visible,
+        Template = template,
+        Properties = properties,
+        Points = polyline
+      };
+    }
+
+    // Text
+
+    return new RectangleObject
+    {
+      ID = id,
+      Name = name,
+      Type = type,
+      X = x,
+      Y = y,
+      Width = width,
+      Height = height,
+      Rotation = rotation,
+      GID = gid,
+      Visible = visible,
+      Template = template,
+      Properties = properties
+    };
+  }
+
+  internal static List<Vector2> ReadPoints(JsonElement element) =>
+    element.GetValueAsList<Vector2>(e =>
+    {
+      var x = e.GetRequiredProperty<float>("x");
+      var y = e.GetRequiredProperty<float>("y");
+      return new Vector2(x, y);
+    });
+
+  internal static Template ReadTemplate(
+    JsonElement element,
+    Func<string, Tileset> externalTilesetResolver,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    var type = element.GetRequiredProperty<string>("type");
+    var tileset = element.GetOptionalPropertyCustom<Tileset?>("tileset", el => ReadTileset(el, externalTilesetResolver, externalTemplateResolver, customTypeDefinitions), null);
+    var @object = element.GetRequiredPropertyCustom<Object>("object", el => ReadObject(el, externalTemplateResolver, customTypeDefinitions));
+
+    return new Template
+    {
+      Tileset = tileset,
+      Object = @object
+    };
+  }
 }
diff --git a/DotTiled/Serialization/Tmj/Tmj.Map.cs b/DotTiled/Serialization/Tmj/Tmj.Map.cs
index 0906b70..ea7313f 100644
--- a/DotTiled/Serialization/Tmj/Tmj.Map.cs
+++ b/DotTiled/Serialization/Tmj/Tmj.Map.cs
@@ -9,7 +9,11 @@ namespace DotTiled;
 
 internal partial class Tmj
 {
-  internal static Map ReadMap(JsonElement element, Func<string, Tileset>? externalTilesetResolver, Func<string, Template> externalTemplateResolver)
+  internal static Map ReadMap(
+    JsonElement element,
+    Func<string, Tileset>? externalTilesetResolver,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
   {
     var version = element.GetRequiredProperty<string>("version");
     var tiledVersion = element.GetRequiredProperty<string>("tiledversion");
@@ -55,10 +59,10 @@ internal partial class Tmj
     var nextObjectID = element.GetRequiredProperty<uint>("nextobjectid");
     var infinite = element.GetOptionalProperty<bool>("infinite", false);
 
-    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", ReadProperties, null);
+    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", el => ReadProperties(el, customTypeDefinitions), null);
 
-    List<BaseLayer> layers = element.GetOptionalPropertyCustom<List<BaseLayer>>("layers", e => e.GetValueAsList<BaseLayer>(ReadLayer), []);
-    List<Tileset> tilesets = element.GetOptionalPropertyCustom<List<Tileset>>("tilesets", e => e.GetValueAsList<Tileset>(el => ReadTileset(el, externalTilesetResolver, externalTemplateResolver)), []);
+    List<BaseLayer> layers = element.GetOptionalPropertyCustom<List<BaseLayer>>("layers", e => e.GetValueAsList<BaseLayer>(el => ReadLayer(el, externalTemplateResolver, customTypeDefinitions)), []);
+    List<Tileset> tilesets = element.GetOptionalPropertyCustom<List<Tileset>>("tilesets", e => e.GetValueAsList<Tileset>(el => ReadTileset(el, externalTilesetResolver, externalTemplateResolver, customTypeDefinitions)), []);
 
     return new Map
     {
diff --git a/DotTiled/Serialization/Tmj/Tmj.Properties.cs b/DotTiled/Serialization/Tmj/Tmj.Properties.cs
index 37b7dd1..2e01749 100644
--- a/DotTiled/Serialization/Tmj/Tmj.Properties.cs
+++ b/DotTiled/Serialization/Tmj/Tmj.Properties.cs
@@ -8,7 +8,9 @@ namespace DotTiled;
 
 internal partial class Tmj
 {
-  internal static Dictionary<string, IProperty> ReadProperties(JsonElement element) =>
+  internal static Dictionary<string, IProperty> ReadProperties(
+    JsonElement element,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions) =>
     element.GetValueAsList<IProperty>(e =>
     {
       var name = e.GetRequiredProperty<string>("name");
@@ -34,20 +36,105 @@ internal partial class Tmj
         PropertyType.Color => new ColorProperty { Name = name, Value = e.GetRequiredPropertyParseable<Color>("value") },
         PropertyType.File => new FileProperty { Name = name, Value = e.GetRequiredProperty<string>("value") },
         PropertyType.Object => new ObjectProperty { Name = name, Value = e.GetRequiredProperty<uint>("value") },
-        PropertyType.Class => ReadClassProperty(e),
+        PropertyType.Class => ReadClassProperty(e, customTypeDefinitions),
         _ => throw new JsonException("Invalid property type")
       };
 
       return property!;
     }).ToDictionary(p => p.Name);
 
-  internal static ClassProperty ReadClassProperty(JsonElement element)
+  internal static ClassProperty ReadClassProperty(
+    JsonElement element,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
   {
     var name = element.GetRequiredProperty<string>("name");
     var propertyType = element.GetRequiredProperty<string>("propertytype");
 
-    var properties = element.GetRequiredPropertyCustom<Dictionary<string, IProperty>>("properties", ReadProperties);
+    var customTypeDef = customTypeDefinitions.FirstOrDefault(ctd => ctd.Name == propertyType);
 
-    return new ClassProperty { Name = name, PropertyType = propertyType, Properties = properties };
+    if (customTypeDef is CustomClassDefinition ccd)
+    {
+      var propsInType = CreateInstanceOfCustomClass(ccd);
+      var props = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>>("value", el => ReadCustomClassProperties(el, ccd, customTypeDefinitions), []);
+
+      var mergedProps = MergeProperties(propsInType, props);
+
+      return new ClassProperty
+      {
+        Name = name,
+        PropertyType = propertyType,
+        Properties = mergedProps
+      };
+    }
+
+    throw new JsonException($"Unknown custom class '{propertyType}'.");
+  }
+
+  internal static Dictionary<string, IProperty> ReadCustomClassProperties(
+    JsonElement element,
+    CustomClassDefinition customClassDefinition,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    Dictionary<string, IProperty> resultingProps = [];
+
+    foreach (var prop in customClassDefinition.Members)
+    {
+      if (!element.TryGetProperty(prop.Name, out var propElement))
+        continue; // Property not present in element, therefore will use default value
+
+      IProperty property = prop.Type switch
+      {
+        PropertyType.String => new StringProperty { Name = prop.Name, Value = propElement.GetValueAs<string>() },
+        PropertyType.Int => new IntProperty { Name = prop.Name, Value = propElement.GetValueAs<int>() },
+        PropertyType.Float => new FloatProperty { Name = prop.Name, Value = propElement.GetValueAs<float>() },
+        PropertyType.Bool => new BoolProperty { Name = prop.Name, Value = propElement.GetValueAs<bool>() },
+        PropertyType.Color => new ColorProperty { Name = prop.Name, Value = Color.Parse(propElement.GetValueAs<string>(), CultureInfo.InvariantCulture) },
+        PropertyType.File => new FileProperty { Name = prop.Name, Value = propElement.GetValueAs<string>() },
+        PropertyType.Object => new ObjectProperty { Name = prop.Name, Value = propElement.GetValueAs<uint>() },
+        PropertyType.Class => ReadClassProperty(propElement, customTypeDefinitions),
+        _ => throw new JsonException("Invalid property type")
+      };
+
+      resultingProps[prop.Name] = property;
+    }
+
+    return resultingProps;
+  }
+
+  internal static Dictionary<string, IProperty> CreateInstanceOfCustomClass(CustomClassDefinition customClassDefinition)
+  {
+    return customClassDefinition.Members.ToDictionary(m => m.Name, m => m.Clone());
+  }
+
+  internal static Dictionary<string, IProperty> MergeProperties(Dictionary<string, IProperty>? baseProperties, Dictionary<string, IProperty> overrideProperties)
+  {
+    if (baseProperties is null)
+      return overrideProperties ?? new Dictionary<string, IProperty>();
+
+    if (overrideProperties is null)
+      return baseProperties;
+
+    var result = baseProperties.ToDictionary(kvp => kvp.Key, kvp => kvp.Value.Clone());
+    foreach (var (key, value) in overrideProperties)
+    {
+      if (!result.TryGetValue(key, out var baseProp))
+      {
+        result[key] = value;
+        continue;
+      }
+      else
+      {
+        if (value is ClassProperty classProp)
+        {
+          ((ClassProperty)baseProp).Properties = MergeProperties(((ClassProperty)baseProp).Properties, classProp.Properties);
+        }
+        else
+        {
+          result[key] = value;
+        }
+      }
+    }
+
+    return result;
   }
 }
diff --git a/DotTiled/Serialization/Tmj/Tmj.Tileset.cs b/DotTiled/Serialization/Tmj/Tmj.Tileset.cs
index 66d42b1..1d0aa6e 100644
--- a/DotTiled/Serialization/Tmj/Tmj.Tileset.cs
+++ b/DotTiled/Serialization/Tmj/Tmj.Tileset.cs
@@ -10,7 +10,11 @@ namespace DotTiled;
 
 internal partial class Tmj
 {
-  internal static Tileset ReadTileset(JsonElement element, Func<string, Tileset>? externalTilesetResolver, Func<string, Template> externalTemplateResolver)
+  internal static Tileset ReadTileset(
+    JsonElement element,
+    Func<string, Tileset>? externalTilesetResolver,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
   {
     var backgroundColor = element.GetOptionalPropertyParseable<Color?>("backgroundcolor", s => Color.Parse(s, CultureInfo.InvariantCulture), null);
     var @class = element.GetOptionalProperty<string>("class", "");
@@ -42,7 +46,7 @@ internal partial class Tmj
       "bottomright" => ObjectAlignment.BottomRight,
       _ => throw new JsonException($"Unknown object alignment '{s}'")
     }, ObjectAlignment.Unspecified);
-    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", ReadProperties, null);
+    var properties = element.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", el => ReadProperties(el, customTypeDefinitions), null);
     var source = element.GetOptionalProperty<string?>("source", null);
     var spacing = element.GetOptionalProperty<uint?>("spacing", null);
     var tileCount = element.GetOptionalProperty<uint?>("tilecount", null);
@@ -55,7 +59,7 @@ internal partial class Tmj
       "grid" => TileRenderSize.Grid,
       _ => throw new JsonException($"Unknown tile render size '{s}'")
     }, TileRenderSize.Tile);
-    var tiles = element.GetOptionalPropertyCustom<List<Tile>>("tiles", ReadTiles, []);
+    var tiles = element.GetOptionalPropertyCustom<List<Tile>>("tiles", el => ReadTiles(el, customTypeDefinitions), []);
     var tileWidth = element.GetOptionalProperty<uint?>("tilewidth", null);
     var transparentColor = element.GetOptionalPropertyParseable<Color?>("transparentcolor", s => Color.Parse(s, CultureInfo.InvariantCulture), null);
     var type = element.GetOptionalProperty<string?>("type", null);
@@ -153,7 +157,9 @@ internal partial class Tmj
     };
   }
 
-  internal static List<Tile> ReadTiles(JsonElement element) =>
+  internal static List<Tile> ReadTiles(
+    JsonElement element,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions) =>
     element.GetValueAsList<Tile>(e =>
     {
       //var animation = e.GetOptionalPropertyCustom<List<Frame>>("animation", ReadFrames, null);
@@ -167,7 +173,7 @@ internal partial class Tmj
       var height = e.GetOptionalProperty<uint>("height", imageHeight ?? 0);
       //var objectGroup = e.GetOptionalPropertyCustom<ObjectLayer?>("objectgroup", ReadObjectLayer, null);
       var probability = e.GetOptionalProperty<float>("probability", 1.0f);
-      var properties = e.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", ReadProperties, null);
+      var properties = e.GetOptionalPropertyCustom<Dictionary<string, IProperty>?>("properties", el => ReadProperties(el, customTypeDefinitions), null);
       // var terrain, replaced by wangsets
       var type = e.GetOptionalProperty<string>("type", "");
 
diff --git a/DotTiled/Serialization/Tmj/TmjMapReader.cs b/DotTiled/Serialization/Tmj/TmjMapReader.cs
index 9aa9675..260cd21 100644
--- a/DotTiled/Serialization/Tmj/TmjMapReader.cs
+++ b/DotTiled/Serialization/Tmj/TmjMapReader.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using System.Text.Json;
@@ -14,18 +15,25 @@ public class TmjMapReader : IMapReader
   private string _jsonString;
   private bool disposedValue;
 
-  public TmjMapReader(string jsonString, Func<string, Tileset> externalTilesetResolver, Func<string, Template> externalTemplateResolver)
+  private readonly IReadOnlyCollection<CustomTypeDefinition> _customTypeDefinitions;
+
+  public TmjMapReader(
+    string jsonString,
+    Func<string, Tileset> externalTilesetResolver,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
   {
     _jsonString = jsonString ?? throw new ArgumentNullException(nameof(jsonString));
     _externalTilesetResolver = externalTilesetResolver ?? throw new ArgumentNullException(nameof(externalTilesetResolver));
     _externalTemplateResolver = externalTemplateResolver ?? throw new ArgumentNullException(nameof(externalTemplateResolver));
+    _customTypeDefinitions = customTypeDefinitions ?? throw new ArgumentNullException(nameof(customTypeDefinitions));
   }
 
   public Map ReadMap()
   {
     var jsonDoc = JsonDocument.Parse(_jsonString);
     var rootElement = jsonDoc.RootElement;
-    return Tmj.ReadMap(rootElement, _externalTilesetResolver, _externalTemplateResolver);
+    return Tmj.ReadMap(rootElement, _externalTilesetResolver, _externalTemplateResolver, _customTypeDefinitions);
   }
 
   protected virtual void Dispose(bool disposing)
diff --git a/DotTiled/Serialization/Tmj/TsjTilesetReader.cs b/DotTiled/Serialization/Tmj/TsjTilesetReader.cs
new file mode 100644
index 0000000..14e5323
--- /dev/null
+++ b/DotTiled/Serialization/Tmj/TsjTilesetReader.cs
@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+
+namespace DotTiled;
+
+public class TsjTilesetReader : ITilesetReader
+{
+  // External resolvers
+  private readonly Func<string, Template> _externalTemplateResolver;
+
+  private readonly string _jsonString;
+  private bool disposedValue;
+
+  private readonly IReadOnlyCollection<CustomTypeDefinition> _customTypeDefinitions;
+
+  public TsjTilesetReader(
+    string jsonString,
+    Func<string, Template> externalTemplateResolver,
+    IReadOnlyCollection<CustomTypeDefinition> customTypeDefinitions)
+  {
+    _jsonString = jsonString ?? throw new ArgumentNullException(nameof(jsonString));
+    _externalTemplateResolver = externalTemplateResolver ?? throw new ArgumentNullException(nameof(externalTemplateResolver));
+    _customTypeDefinitions = customTypeDefinitions ?? throw new ArgumentNullException(nameof(customTypeDefinitions));
+  }
+
+  public Tileset ReadTileset()
+  {
+    var jsonDoc = System.Text.Json.JsonDocument.Parse(_jsonString);
+    var rootElement = jsonDoc.RootElement;
+    return Tmj.ReadTileset(
+      rootElement,
+      _ => throw new NotSupportedException("External tilesets cannot refer to other external tilesets."),
+      _externalTemplateResolver,
+      _customTypeDefinitions);
+  }
+
+  protected virtual void Dispose(bool disposing)
+  {
+    if (!disposedValue)
+    {
+      if (disposing)
+      {
+        // TODO: dispose managed state (managed objects)
+      }
+
+      // TODO: free unmanaged resources (unmanaged objects) and override finalizer
+      // TODO: set large fields to null
+      disposedValue = true;
+    }
+  }
+
+  // // TODO: override finalizer only if 'Dispose(bool disposing)' has code to free unmanaged resources
+  // ~TsjTilesetReader()
+  // {
+  //     // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+  //     Dispose(disposing: false);
+  // }
+
+  public void Dispose()
+  {
+    // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+    Dispose(disposing: true);
+    System.GC.SuppressFinalize(this);
+  }
+}