diff --git a/src/backend/chat/migrations/0002_fix_source_type_in_messages.py b/src/backend/chat/migrations/0002_fix_source_type_in_messages.py
new file mode 100644
index 0000000..4524790
--- /dev/null
+++ b/src/backend/chat/migrations/0002_fix_source_type_in_messages.py
@@ -0,0 +1,54 @@
+# Generated by Django 5.2.3 on 2025-09-15 11:47
+from django.db import migrations
+
+
+def forwards_func(apps, schema_editor):
+    """Use raw SQL to replace "source_type" with "sourceType" in the messages field."""
+    with schema_editor.connection.cursor() as cursor:
+        cursor.execute("""
+            UPDATE chat_chatconversation 
+            SET messages = REPLACE(messages::text, '"source_type"', '"sourceType"')::jsonb
+            WHERE messages::text LIKE '%"source_type"%'
+        """)
+    with schema_editor.connection.cursor() as cursor:
+        cursor.execute("""
+            UPDATE chat_chatconversation
+            SET ui_messages = REPLACE(ui_messages::text, '"source_type"', '"sourceType"')::jsonb
+            WHERE ui_messages::text LIKE '%"source_type"%'
+        """)
+
+
+def reverse_func(apps, schema_editor):
+    """Use raw SQL to replace "sourceType" with "source_type" in the messages field."""
+    with schema_editor.connection.cursor() as cursor:
+        cursor.execute("""
+            UPDATE chat_chatconversation 
+            SET messages = REPLACE(messages::text, '"sourceType"', '"source_type"')::jsonb
+            WHERE messages::text LIKE '%"sourceType"%'
+        """)
+    with schema_editor.connection.cursor() as cursor:
+        cursor.execute("""
+            UPDATE chat_chatconversation
+            SET ui_messages = REPLACE(ui_messages::text, '"sourceType"', '"source_type"')::jsonb
+            WHERE ui_messages::text LIKE '%"sourceType"%'
+        """)
+
+
+class Migration(migrations.Migration):
+    """
+    Rename source_type to sourceType in messages field of ChatConversation model.
+
+    Warning: This migration is not fail-safe, if the messages field contains
+    other occurrences of "source_type" or "sourceType" in other contexts, they will
+    also be replaced. Also, if the messages field is very large, this migration
+    may take a long time to run.
+    => OK because we are only in development phase.
+    """
+
+    dependencies = [
+        ("chat", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.RunPython(forwards_func, reverse_func),
+    ]