diff --git a/app/user_manager.py b/app/user_manager.py
index e2c00dab2..ac4fca781 100644
--- a/app/user_manager.py
+++ b/app/user_manager.py
@@ -27,8 +27,8 @@ def get_file_info(path: str, relative_to: str) -> FileInfo:
     return {
         "path": os.path.relpath(path, relative_to).replace(os.sep, '/'),
         "size": os.path.getsize(path),
-        "modified": os.path.getmtime(path),
-        "created": os.path.getctime(path)
+        "modified": int(os.path.getmtime(path) * 1000),
+        "created": int(os.path.getctime(path) * 1000),
     }
 
 
diff --git a/tests-unit/prompt_server_test/user_manager_test.py b/tests-unit/prompt_server_test/user_manager_test.py
index b939d8e68..27118400f 100644
--- a/tests-unit/prompt_server_test/user_manager_test.py
+++ b/tests-unit/prompt_server_test/user_manager_test.py
@@ -69,7 +69,11 @@ async def test_listuserdata_full_info(aiohttp_client, app, tmp_path):
     assert len(result) == 1
     assert result[0]["path"] == "file1.txt"
     assert "size" in result[0]
-    assert "modified" in result[0]
+    assert isinstance(result[0]["modified"], int)
+    assert isinstance(result[0]["created"], int)
+    # Verify millisecond magnitude (timestamps after year 2000 in ms are > 946684800000)
+    assert result[0]["modified"] > 946684800000
+    assert result[0]["created"] > 946684800000
 
 
 async def test_listuserdata_split_path(aiohttp_client, app, tmp_path):