diff --git a/backend/common/src/helper.py b/backend/common/src/helper.py
index dbf238ce..a29da9a2 100644
--- a/backend/common/src/helper.py
+++ b/backend/common/src/helper.py
@@ -110,6 +110,8 @@ def date_parser(timestamp: int | str | None) -> str | None:
 
     if isinstance(timestamp, int):
         date_obj = datetime.fromtimestamp(timestamp, tz=timezone.utc)
+    elif isinstance(timestamp, str) and timestamp.isdigit():
+        date_obj = datetime.fromtimestamp(int(timestamp), tz=timezone.utc)
     elif isinstance(timestamp, str):
         date_obj = datetime.strptime(timestamp, "%Y-%m-%d")
         date_obj = date_obj.replace(tzinfo=timezone.utc)
diff --git a/backend/common/tests/test_src/test_helper.py b/backend/common/tests/test_src/test_helper.py
index 013e774b..73578a76 100644
--- a/backend/common/tests/test_src/test_helper.py
+++ b/backend/common/tests/test_src/test_helper.py
@@ -26,6 +26,13 @@ def test_date_parser_with_int():
     assert date_parser(timestamp) == expected_date
 
 
+def test_date_parser_with_digit():
+    """unix timestamp"""
+    timestamp = "1621539600"
+    expected_date = "2021-05-20T19:40:00+00:00"
+    assert date_parser(timestamp) == expected_date
+
+
 def test_date_parser_with_str():
     """iso timestamp"""
     date_str = "2021-05-21"