diff --git a/app/MindWork AI Studio/Settings/DataModel/MetadataJsonConverter.cs b/app/MindWork AI Studio/Settings/DataModel/MetadataJsonConverter.cs
index f800ef8a..66d1be39 100644
--- a/app/MindWork AI Studio/Settings/DataModel/MetadataJsonConverter.cs	
+++ b/app/MindWork AI Studio/Settings/DataModel/MetadataJsonConverter.cs	
@@ -5,47 +5,33 @@ namespace AIStudio.Settings.DataModel;
 
 public class MetadataJsonConverter : JsonConverter<Metadata>
 {
+    private static readonly Dictionary<string, Type> TYPE_MAP = new()
+    {
+        { "Text", typeof(TextMetadata) },
+        { "Pdf", typeof(PdfMetadata) },
+        { "Spreadsheet", typeof(SpreadsheetMetadata) },
+        { "Presentation", typeof(PresentationMetadata) },
+        { "Image", typeof(ImageMetadata) },
+        { "Document", typeof(DocumentMetadata) }
+    };
+
     public override Metadata? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
+        using var jsonDoc = JsonDocument.ParseValue(ref reader);
+        var root = jsonDoc.RootElement;
+        var rawText = root.GetRawText();
         
-        using (var jsonDoc = JsonDocument.ParseValue(ref reader))
+        var propertyName = root.EnumerateObject()
+            .Select(p => p.Name)
+            .FirstOrDefault(name => TYPE_MAP.ContainsKey(name));
+            
+        if (propertyName != null && TYPE_MAP.TryGetValue(propertyName, out var metadataType))
         {
-            var root = jsonDoc.RootElement;
-
-            if (root.TryGetProperty("Text", out _))
-            {
-                return JsonSerializer.Deserialize<TextMetadata>(root.GetRawText(), options);
-            }
-            else if (root.TryGetProperty("Pdf", out _))
-            {
-                return JsonSerializer.Deserialize<PdfMetadata>(root.GetRawText(), options);
-            }
-            else if (root.TryGetProperty("Spreadsheet", out _))
-            {
-                return JsonSerializer.Deserialize<SpreadsheetMetadata>(root.GetRawText(), options);
-            }
-            else if (root.TryGetProperty("Presentation", out _))
-            {
-                return JsonSerializer.Deserialize<PresentationMetadata>(root.GetRawText(), options);
-            }
-            else if (root.TryGetProperty("Image", out _))
-            {
-                return JsonSerializer.Deserialize<ImageMetadata>(root.GetRawText(), options);
-            }
-            else if (root.TryGetProperty("Document", out _))
-            {
-                return JsonSerializer.Deserialize<DocumentMetadata>(root.GetRawText(), options);
-            }
-            else
-            {
-                // Unbekannter Typ
-                return null;
-            }
+            return (Metadata?)JsonSerializer.Deserialize(rawText, metadataType, options);
         }
+        
+        return null;
     }
 
-    public override void Write(Utf8JsonWriter writer, Metadata value, JsonSerializerOptions options)
-    {
-        throw new NotImplementedException();
-    }
+    public override void Write(Utf8JsonWriter writer, Metadata value, JsonSerializerOptions options) => JsonSerializer.Serialize(writer, value, value.GetType(), options);
 }
\ No newline at end of file
diff --git a/app/MindWork AI Studio/Settings/DataModel/SseEvent.cs b/app/MindWork AI Studio/Settings/DataModel/SseEvent.cs
index 391df2d5..a1aa4295 100644
--- a/app/MindWork AI Studio/Settings/DataModel/SseEvent.cs	
+++ b/app/MindWork AI Studio/Settings/DataModel/SseEvent.cs	
@@ -5,10 +5,10 @@ namespace AIStudio.Settings.DataModel;
 public class SseEvent
 {
     [JsonPropertyName("content")] 
-    public string Content { get; set; }
+    public string? Content { get; set; }
 
     [JsonPropertyName("metadata")] 
-    public Metadata Metadata { get; set; }
+    public Metadata? Metadata { get; set; }
 }
 
 [JsonConverter(typeof(MetadataJsonConverter))]
@@ -17,75 +17,71 @@ public abstract class Metadata;
 public class TextMetadata : Metadata
 {
     [JsonPropertyName("Text")]
-    public TextDetails Text { get; set; }
+    public TextDetails? Text { get; set; }
 }
 
 public class TextDetails
 {
     [JsonPropertyName("line_number")]
-    public int LineNumber { get; set; }
+    public int? LineNumber { get; set; }
 }
 
 public class PdfMetadata : Metadata
 {
     [JsonPropertyName("Pdf")] 
-    public PdfDetails Pdf { get; set; }
+    public PdfDetails? Pdf { get; set; }
 }
 
 public class PdfDetails
 {
     [JsonPropertyName("page_number")] 
-    public int PageNumber { get; set; }
+    public int? PageNumber { get; set; }
 }
 
 public class SpreadsheetMetadata : Metadata
 {
     [JsonPropertyName("Spreadsheet")] 
-    public SpreadsheetDetails Spreadsheet { get; set; }
+    public SpreadsheetDetails? Spreadsheet { get; set; }
 }
 
 public class SpreadsheetDetails
 {
     [JsonPropertyName("sheet_name")] 
-    public string SheetName { get; set; }
+    public string? SheetName { get; set; }
 
     [JsonPropertyName("row_number")] 
-    public int RowNumber { get; set; }
+    public int? RowNumber { get; set; }
 }
 
 public class DocumentMetadata : Metadata {}
 
+public class ImageMetadata: Metadata {}
+
 public class PresentationMetadata : Metadata
 {
     [JsonPropertyName("Presentation")] 
-    public PresentationDetails Presentation { get; set; }
+    public PresentationDetails? Presentation { get; set; }
 }
 
 public class PresentationDetails
 {
     [JsonPropertyName("slide_number")] 
-    public int SlideNumber { get; set; }
+    public int? SlideNumber { get; set; }
 
     [JsonPropertyName("image")] 
-    public ImageData Image { get; set; }
+    public PptxImageData? Image { get; set; }
 }
 
-public class ImageMetadata : Metadata
-{
-    [JsonPropertyName("Image")] 
-    public object Image { get; set; }
-}
-
-public class ImageData
+public class PptxImageData
 {
     [JsonPropertyName("id")] 
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
     [JsonPropertyName("content")] 
-    public string Content { get; set; }
+    public string? Content { get; set; }
 
     [JsonPropertyName("segment")] 
-    public int Segment { get; set; }
+    public int? Segment { get; set; }
 
     [JsonPropertyName("is_end")] 
     public bool IsEnd { get; set; }