diff --git a/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs b/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs
index dd3af7e..87199b1 100644
--- a/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs
+++ b/AyCode.Core.Serializers.SourceGenerator/AcBinarySourceGenerator.cs
@@ -79,21 +79,9 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             }
         }
 
-        foreach (var member in typeSymbol.GetMembers())
+        foreach (var p in GetAllSerializablePropertySymbols(typeSymbol))
         {
-            if (member is IPropertySymbol p &&
-                p.DeclaredAccessibility == Accessibility.Public &&
-                p.GetMethod != null && p.SetMethod != null &&
-                !p.IsIndexer && !p.IsStatic)
-            {
-                var hasIgnore = p.GetAttributes().Any(a =>
-                {
-                    var name = a.AttributeClass?.Name ?? "";
-                    return name == "JsonIgnoreAttribute" || name == "IgnoreMemberAttribute" || name == "BsonIgnoreAttribute";
-                });
-                if (hasIgnore) continue;
-
-                // String interning attribútum detektálás (null = no attr, true/false = explicit)
+            // String interning attribútum detektálás (null = no attr, true/false = explicit)
                 bool? stringInternAttr = null;
                 if (!enableInternString)
                 {
@@ -137,8 +125,9 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
                         ? namedPropType.OriginalDefinition
                         : p.Type;
 
-                    hasGenWriter = resolvedType.GetAttributes().Any(a =>
-                        a.AttributeClass?.ToDisplayString() == AttributeName);
+                    hasGenWriter = resolvedType.Locations.Any(l => l.IsInSource)
+                        && resolvedType.GetAttributes().Any(a =>
+                            a.AttributeClass?.ToDisplayString() == AttributeName);
 
                     if (hasGenWriter)
                     {
@@ -236,8 +225,9 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
                         {
                             var resolvedElem = elemType is INamedTypeSymbol namedElem
                                 ? namedElem.OriginalDefinition : elemType;
-                            elemHasGenWriter = resolvedElem.GetAttributes().Any(a =>
-                                a.AttributeClass?.ToDisplayString() == AttributeName);
+                            elemHasGenWriter = resolvedElem.Locations.Any(l => l.IsInSource)
+                                && resolvedElem.GetAttributes().Any(a =>
+                                    a.AttributeClass?.ToDisplayString() == AttributeName);
                             if (elemHasGenWriter)
                             {
                                 // Read element type's EnableMetadataFeature
@@ -297,8 +287,9 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
                         if (dictValueKind == PropertyTypeKind.Complex)
                         {
                             var resolvedValue = valueType is INamedTypeSymbol nvt ? nvt.OriginalDefinition : valueType;
-                            dictValueHasGenWriter = resolvedValue.GetAttributes().Any(a =>
-                                a.AttributeClass?.ToDisplayString() == AttributeName);
+                            dictValueHasGenWriter = resolvedValue.Locations.Any(l => l.IsInSource)
+                                && resolvedValue.GetAttributes().Any(a =>
+                                    a.AttributeClass?.ToDisplayString() == AttributeName);
                             if (dictValueHasGenWriter)
                             {
                                 var vfn = BuildFlatName((INamedTypeSymbol)resolvedValue);
@@ -342,7 +333,6 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
                     propEnableMetadata, elemEnableMetadata,
                     childNeedsIdScan, childNeedsAllRefScan, childNeedsInternScan,
                     elemNeedsIdScan, elemNeedsAllRefScan, elemNeedsInternScan));
-            }
         }
 
         // IId<T>: Id first (index 0), then alphabetical — matches runtime TypeMetadataBase ordering
@@ -361,7 +351,8 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
             }
         }
 
-        properties.Sort((a, b) => string.Compare(a.Name, b.Name, StringComparison.Ordinal));
+        // Properties are already in runtime-matching order from GetAllSerializablePropertySymbols:
+        // derived → base, each level sorted alphabetically (matches TypeMetadataBase.GetUnfilteredProperties).
 
         var className = BuildFlatName(typeSymbol);
         var typeNameHash = ComputeFnvHash(typeSymbol.Name);
@@ -1214,16 +1205,10 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
         var writer = p.WriterClassName;
         var nextDepth = "depth + 1";
 
-        if (p.IsNullable)
-        {
-            sb.AppendLine($"{i}if ({a} == null) context.WriteByte(BinaryTypeCode.PropertySkip);");
-            sb.AppendLine($"{i}else");
-            sb.AppendLine($"{i}{{");
-        }
-        else
-        {
-            sb.AppendLine($"{i}{{");
-        }
+        // Reference type properties can always be null at runtime regardless of nullable annotation
+        sb.AppendLine($"{i}if ({a} == null) context.WriteByte(BinaryTypeCode.PropertySkip);");
+        sb.AppendLine($"{i}else");
+        sb.AppendLine($"{i}{{");
 
         // MaxDepth check — matches WriteObjectGenerated
         sb.AppendLine($"{i}    if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
@@ -1351,19 +1336,11 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
     {
         var writer = p.ElementWriterClassName;
 
-        if (p.IsNullable)
-        {
-            sb.AppendLine($"{i}if ({a} == null) context.WriteByte(BinaryTypeCode.PropertySkip);");
-            sb.AppendLine($"{i}else if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
-            sb.AppendLine($"{i}else");
-            sb.AppendLine($"{i}{{");
-        }
-        else
-        {
-            sb.AppendLine($"{i}if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
-            sb.AppendLine($"{i}else");
-            sb.AppendLine($"{i}{{");
-        }
+        // Reference type collections can always be null at runtime regardless of nullable annotation
+        sb.AppendLine($"{i}if ({a} == null) context.WriteByte(BinaryTypeCode.PropertySkip);");
+        sb.AppendLine($"{i}else if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
+        sb.AppendLine($"{i}else");
+        sb.AppendLine($"{i}{{");
 
         sb.AppendLine($"{i}    context.WriteByte(BinaryTypeCode.Array);");
 
@@ -1587,19 +1564,11 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
         var keyType = p.DictKeyTypeName ?? "object";
         var valType = p.DictValueTypeName ?? "object";
 
-        if (p.IsNullable)
-        {
-            sb.AppendLine($"{i}if ({a} == null) context.WriteByte(BinaryTypeCode.PropertySkip);");
-            sb.AppendLine($"{i}else if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
-            sb.AppendLine($"{i}else");
-            sb.AppendLine($"{i}{{");
-        }
-        else
-        {
-            sb.AppendLine($"{i}if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
-            sb.AppendLine($"{i}else");
-            sb.AppendLine($"{i}{{");
-        }
+        // Reference type dictionaries can always be null at runtime regardless of nullable annotation
+        sb.AppendLine($"{i}if ({a} == null) context.WriteByte(BinaryTypeCode.PropertySkip);");
+        sb.AppendLine($"{i}else if (depth > context.MaxDepth) context.WriteByte(BinaryTypeCode.Null);");
+        sb.AppendLine($"{i}else");
+        sb.AppendLine($"{i}{{");
 
         sb.AppendLine($"{i}    context.WriteByte(BinaryTypeCode.Dictionary);");
         sb.AppendLine($"{i}    context.WriteVarUInt((uint){a}.Count);");
@@ -2749,21 +2718,8 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
         var needsInternScan = false;
 
         // Check properties for string interning or complex children
-        foreach (var member in type.GetMembers())
+        foreach (var p in GetAllSerializablePropertySymbols(type))
         {
-            if (member is not IPropertySymbol p ||
-                p.DeclaredAccessibility != Accessibility.Public ||
-                p.GetMethod == null || p.SetMethod == null ||
-                p.IsIndexer || p.IsStatic)
-                continue;
-
-            var hasIgnore = p.GetAttributes().Any(a =>
-            {
-                var name = a.AttributeClass?.Name ?? "";
-                return name == "JsonIgnoreAttribute" || name == "IgnoreMemberAttribute" || name == "BsonIgnoreAttribute";
-            });
-            if (hasIgnore) continue;
-
             // Early exit: if all flags are already true, no need to check more properties
             if (needsIdScan && needsAllRefScan && needsInternScan) break;
 
@@ -2850,35 +2806,62 @@ public class AcBinarySourceGenerator : IIncrementalGenerator
     /// <summary>
     /// Computes FNV-1a hashes for all serializable properties of a child type.
     /// Property filtering and ordering matches runtime TypeMetadataBase exactly:
-    /// public get+set, non-indexer, non-static, no ignore attributes, sorted alphabetically.
+    /// derived → base, each level sorted alphabetically, with ignore attribute filtering.
     /// </summary>
     private static int[] ComputeChildPropertyHashes(ITypeSymbol resolvedType)
     {
-        var propNames = new List<string>();
-        foreach (var member in resolvedType.GetMembers())
-        {
-            if (member is IPropertySymbol cp &&
-                cp.DeclaredAccessibility == Accessibility.Public &&
-                cp.GetMethod != null && cp.SetMethod != null &&
-                !cp.IsIndexer && !cp.IsStatic)
-            {
-                var hasIgnore = cp.GetAttributes().Any(a =>
-                {
-                    var name = a.AttributeClass?.Name ?? "";
-                    return name == "JsonIgnoreAttribute" || name == "IgnoreMemberAttribute" || name == "BsonIgnoreAttribute";
-                });
-                if (hasIgnore) continue;
-                propNames.Add(cp.Name);
-            }
-        }
-
-        propNames.Sort(StringComparer.Ordinal);
-
-        return propNames.Select(ComputeFnvHash).ToArray();
+        // Use hierarchy-walking helper — order matches runtime TypeMetadataBase
+        var props = GetAllSerializablePropertySymbols(resolvedType);
+        return props.Select(p => ComputeFnvHash(p.Name)).ToArray();
     }
 
     #endregion
 
+    /// <summary>
+    /// Collects all serializable property symbols from the full inheritance hierarchy.
+    /// Order matches runtime TypeMetadataBase.GetUnfilteredProperties exactly:
+    /// derived → base, each level sorted alphabetically by name.
+    /// Filters: public, get+set, non-indexer, non-static, no ignore attributes.
+    /// Deduplicates by name (most-derived override wins).
+    /// </summary>
+    private static List<IPropertySymbol> GetAllSerializablePropertySymbols(ITypeSymbol typeSymbol)
+    {
+        var result = new List<IPropertySymbol>();
+        var seen = new HashSet<string>();
+
+        for (var currentType = typeSymbol as INamedTypeSymbol;
+             currentType != null && currentType.SpecialType != SpecialType.System_Object;
+             currentType = currentType.BaseType)
+        {
+            var levelProps = new List<IPropertySymbol>();
+
+            foreach (var member in currentType.GetMembers())
+            {
+                if (member is IPropertySymbol p &&
+                    p.DeclaredAccessibility == Accessibility.Public &&
+                    p.GetMethod != null && p.SetMethod != null &&
+                    !p.IsIndexer && !p.IsStatic &&
+                    seen.Add(p.Name)) // dedup: most-derived wins
+                {
+                    var hasIgnore = p.GetAttributes().Any(a =>
+                    {
+                        var name = a.AttributeClass?.Name ?? "";
+                        return name == "JsonIgnoreAttribute" || name == "IgnoreMemberAttribute" || name == "BsonIgnoreAttribute";
+                    });
+                    if (hasIgnore) continue;
+
+                    levelProps.Add(p);
+                }
+            }
+
+            // Sort each level alphabetically — matches runtime OrderBy(p => p.Name, Ordinal)
+            levelProps.Sort((a, b) => string.Compare(a.Name, b.Name, StringComparison.Ordinal));
+            result.AddRange(levelProps);
+        }
+
+        return result;
+    }
+
     #region Type analysis
 
     private static bool IsNullableVT(ITypeSymbol t) =>
diff --git a/AyCode.Core/Properties/AssemblyInfo.cs b/AyCode.Core/Properties/AssemblyInfo.cs
index 70e480e..0493a4b 100644
--- a/AyCode.Core/Properties/AssemblyInfo.cs
+++ b/AyCode.Core/Properties/AssemblyInfo.cs
@@ -4,3 +4,4 @@ using System.Runtime.CompilerServices;
 [assembly: InternalsVisibleTo("AyCode.Core.Tests")]
 [assembly: InternalsVisibleTo("AyCode.Core.Tests.Internal")]
 [assembly: InternalsVisibleTo("AyCode.Benchmark")]
+[assembly: InternalsVisibleTo("FruitBank.Common")]
diff --git a/AyCode.Core/Serializers/Binaries/AcBinarySerializerOptions.cs b/AyCode.Core/Serializers/Binaries/AcBinarySerializerOptions.cs
index 16d2b52..dc76c95 100644
--- a/AyCode.Core/Serializers/Binaries/AcBinarySerializerOptions.cs
+++ b/AyCode.Core/Serializers/Binaries/AcBinarySerializerOptions.cs
@@ -99,7 +99,7 @@ public sealed class AcBinarySerializerOptions : AcSerializerOptions
     /// All: All strings within length limits are interned (legacy behavior).
     /// Default: All
     /// </summary>
-    public StringInterningMode UseStringInterning { get; set; } = StringInterningMode.Attribute;
+    public StringInterningMode UseStringInterning { get; set; } = StringInterningMode.All;
 
     /// <summary>
     /// When true, checks for duplicate property name hashes during serialization (UseMetadata mode).