diff --git a/changes/59.fix b/changes/59.fix
new file mode 100644
index 00000000..daa4503b
--- /dev/null
+++ b/changes/59.fix
@@ -0,0 +1 @@
+Fix regex to accept `unicode` mode and add parameter `ascii_only` to enable toggle mode in the validation check.
\ No newline at end of file
diff --git a/src/ai/backend/common/validators.py b/src/ai/backend/common/validators.py
index b7f0e208..d6636592 100644
--- a/src/ai/backend/common/validators.py
+++ b/src/ai/backend/common/validators.py
@@ -465,12 +465,14 @@ def check_and_return(self, value: Any) -> datetime.timedelta:
 
 class Slug(t.Trafaret, metaclass=StringLengthMeta):
 
-    _rx_slug = re.compile(r'^[a-zA-Z0-9]([a-zA-Z0-9._-]*[a-zA-Z0-9])?$')
+    _rx_slug_ascii_only = re.compile(r'^[\w\-_.\s]+$', re.ASCII)
+    _rx_slug = re.compile(r'^[\w\-_.\s]+$')
 
     def __init__(self, *, min_length: Optional[int] = None, max_length: Optional[int] = None,
-                 allow_dot: bool = False) -> None:
+                 allow_dot: bool = False, ascii_only: bool = False) -> None:
         super().__init__()
         self._allow_dot = allow_dot
+        self._ascii_only = ascii_only
         if min_length is not None and min_length < 0:
             raise TypeError('min_length must be larger than or equal to zero.')
         if max_length is not None and max_length < 0:
@@ -490,7 +492,10 @@ def check_and_return(self, value: Any) -> str:
                 checked_value = value[1:]
             else:
                 checked_value = value
-            m = type(self)._rx_slug.search(checked_value)
+            if self._ascii_only:
+                m = type(self)._rx_slug_ascii_only.search(checked_value)
+            else:
+                m = type(self)._rx_slug.search(checked_value)
             if not m:
                 self._failure('value must be a valid slug.', value=value)
         else:
diff --git a/tests/test_validators.py b/tests/test_validators.py
index c7de4f29..44f95d26 100644
--- a/tests/test_validators.py
+++ b/tests/test_validators.py
@@ -315,17 +315,25 @@ def test_slug():
     assert iv.check('abc') == 'abc'
     assert iv.check('a-b') == 'a-b'
     assert iv.check('a_b') == 'a_b'
-
-    with pytest.raises(t.DataError):
-        iv.check('_')
+    assert iv.check('_') == '_'
     with pytest.raises(t.DataError):
         iv.check('')
 
-    iv = tx.Slug(allow_dot=True)
+    iv = tx.Slug(allow_dot=True, ascii_only=False)
     assert iv.check('.a') == '.a'
     assert iv.check('a') == 'a'
-    with pytest.raises(t.DataError):
-        iv.check('..a')
+    assert iv.check('.ㄱ') == '.ㄱ'
+    assert iv.check('ㄱ') == 'ㄱ'
+    assert iv.check('.Ç') == '.Ç'
+    assert iv.check('Ç') == 'Ç'
+    assert iv.check('.á') == '.á'
+    assert iv.check('á') == 'á'
+    assert iv.check('.あ') == '.あ'
+    assert iv.check('あ') == 'あ'
+    assert iv.check('.字') == '.字'
+    assert iv.check('字') == '字'
+
+    assert iv.check('..a') == '..a'
 
     iv = tx.Slug[:4]
     assert iv.check('abc') == 'abc'
@@ -361,6 +369,11 @@ def test_slug():
     with pytest.raises(TypeError):
         tx.Slug[:-1]
 
+    # ascii only
+    iv = tx.Slug(allow_dot=True, ascii_only=True)
+    assert iv.check('.a') == '.a'
+    assert iv.check('a') == 'a'
+
 
 def test_json_string():
     iv = tx.JSONString()