diff --git a/app/src/main/java/com/example/notesai/data/model/Category.kt b/app/src/main/java/com/example/notesai/data/model/Category.kt
new file mode 100644
index 0000000..47b2f90
--- /dev/null
+++ b/app/src/main/java/com/example/notesai/data/model/Category.kt
@@ -0,0 +1,12 @@
+// File: data/model/Category.kt
+package com.example.notesai.data.model
+
+import java.util.UUID
+
+data class Category(
+    val id: String = UUID.randomUUID().toString(),
+    val name: String,
+    val gradientStart: Long,
+    val gradientEnd: Long,
+    val timestamp: Long = System.currentTimeMillis()
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/notesai/data/model/ChatMessage.kt b/app/src/main/java/com/example/notesai/data/model/ChatMessage.kt
new file mode 100644
index 0000000..2c19659
--- /dev/null
+++ b/app/src/main/java/com/example/notesai/data/model/ChatMessage.kt
@@ -0,0 +1,11 @@
+// File: data/model/ChatMessage.kt
+package com.example.notesai.data.model
+
+import java.util.UUID
+
+data class ChatMessage(
+    val id: String = UUID.randomUUID().toString(),
+    val message: String,
+    val isUser: Boolean,
+    val timestamp: Long = System.currentTimeMillis()
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/notesai/data/model/Note.kt b/app/src/main/java/com/example/notesai/data/model/Note.kt
new file mode 100644
index 0000000..b5e3e36
--- /dev/null
+++ b/app/src/main/java/com/example/notesai/data/model/Note.kt
@@ -0,0 +1,15 @@
+// File: data/model/Note.kt
+package com.example.notesai.data.model
+
+import java.util.UUID
+
+data class Note(
+    val id: String = UUID.randomUUID().toString(),
+    val categoryId: String,
+    val title: String,
+    val content: String,
+    val timestamp: Long = System.currentTimeMillis(),
+    val isArchived: Boolean = false,
+    val isDeleted: Boolean = false,
+    val isPinned: Boolean = false
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/notesai/data/model/SerializableModels.kt b/app/src/main/java/com/example/notesai/data/model/SerializableModels.kt
new file mode 100644
index 0000000..9e61444
--- /dev/null
+++ b/app/src/main/java/com/example/notesai/data/model/SerializableModels.kt
@@ -0,0 +1,67 @@
+// File: data/model/SerializableModels.kt
+package com.example.notesai.data.model
+
+import android.annotation.SuppressLint
+import kotlinx.serialization.Serializable
+
+@SuppressLint("UnsafeOptInUsageError")
+@Serializable
+data class SerializableCategory(
+    val id: String,
+    val name: String,
+    val gradientStart: Long,
+    val gradientEnd: Long,
+    val timestamp: Long
+)
+
+@SuppressLint("UnsafeOptInUsageError")
+@Serializable
+data class SerializableNote(
+    val id: String,
+    val categoryId: String,
+    val title: String,
+    val content: String,
+    val timestamp: Long,
+    val isArchived: Boolean,
+    val isDeleted: Boolean,
+    val isPinned: Boolean
+)
+
+// Extension functions untuk konversi
+fun Category.toSerializable() = SerializableCategory(
+    id = id,
+    name = name,
+    gradientStart = gradientStart,
+    gradientEnd = gradientEnd,
+    timestamp = timestamp
+)
+
+fun SerializableCategory.toCategory() = Category(
+    id = id,
+    name = name,
+    gradientStart = gradientStart,
+    gradientEnd = gradientEnd,
+    timestamp = timestamp
+)
+
+fun Note.toSerializable() = SerializableNote(
+    id = id,
+    categoryId = categoryId,
+    title = title,
+    content = content,
+    timestamp = timestamp,
+    isArchived = isArchived,
+    isDeleted = isDeleted,
+    isPinned = isPinned
+)
+
+fun SerializableNote.toNote() = Note(
+    id = id,
+    categoryId = categoryId,
+    title = title,
+    content = content,
+    timestamp = timestamp,
+    isArchived = isArchived,
+    isDeleted = isDeleted,
+    isPinned = isPinned
+)
\ No newline at end of file