diff --git a/litellm/__init__.py b/litellm/__init__.py
index d75f47567a5..4fc71e12700 100644
--- a/litellm/__init__.py
+++ b/litellm/__init__.py
@@ -305,6 +305,9 @@ return_response_headers: bool = (
     False  # get response headers from LLM Api providers - example x-remaining-requests,
 )
 enable_json_schema_validation: bool = False
+enable_key_alias_format_validation: bool = (
+    False  # opt-in validation of key_alias format on /key/generate and /key/update
+)
 ####################
 logging: bool = True
 enable_loadbalancing_on_batch_endpoints: Optional[bool] = None
diff --git a/litellm/proxy/management_endpoints/key_management_endpoints.py b/litellm/proxy/management_endpoints/key_management_endpoints.py
index 072d4181c68..3b54a79a738 100644
--- a/litellm/proxy/management_endpoints/key_management_endpoints.py
+++ b/litellm/proxy/management_endpoints/key_management_endpoints.py
@@ -5041,12 +5041,18 @@ def _validate_key_alias_format(key_alias: Optional[str]) -> None:
     """
     Validate the format of the key_alias.
 
-    Rules:
+    Gated behind ``litellm.enable_key_alias_format_validation`` (default **False**).
+    When disabled, no validation is performed so existing workflows are not broken.
+
+    Rules (when enabled):
     - None is OK (no alias).
     - Otherwise must be 2–255 chars
     - start/end with alphanumeric
-    - only allow a-zA-Z0-9_-/.
+    - only allow a-zA-Z0-9_-/.@
     """
+    if not litellm.enable_key_alias_format_validation:
+        return
+
     if key_alias is None:
         return
 
diff --git a/tests/test_litellm/proxy/management_endpoints/test_key_management_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_key_management_endpoints.py
index 2533f0d66d9..dc79322d57b 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_key_management_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_key_management_endpoints.py
@@ -2,6 +2,7 @@ import json
 import os
 import sys
 
+import litellm
 import pytest
 import yaml
 from fastapi.testclient import TestClient
@@ -6672,8 +6673,21 @@ async def test_key_aliases_admin_sees_all():
 
 
 class TestValidateKeyAliasFormat:
+    def test_validation_skipped_when_flag_disabled(self):
+        """When enable_key_alias_format_validation is False (default), no validation occurs."""
+        from litellm.proxy.management_endpoints.key_management_endpoints import _validate_key_alias_format
+
+        litellm.enable_key_alias_format_validation = False
+        # Even invalid aliases should pass silently when the flag is off
+        _validate_key_alias_format(None)
+        _validate_key_alias_format("")
+        _validate_key_alias_format("!invalid!")
+        _validate_key_alias_format("a" * 256)
+
     def test_validate_key_alias_format_valid(self):
         from litellm.proxy.management_endpoints.key_management_endpoints import _validate_key_alias_format
+
+        litellm.enable_key_alias_format_validation = True
         # Valid cases
         _validate_key_alias_format(None)  # OK
         _validate_key_alias_format("valid-alias")
@@ -6684,11 +6698,13 @@ class TestValidateKeyAliasFormat:
         _validate_key_alias_format("my-key-123")
         _validate_key_alias_format("user/user@example.com")
         _validate_key_alias_format("team/user@example.com")
+        litellm.enable_key_alias_format_validation = False
 
     def test_validate_key_alias_format_invalid(self):
         from litellm.proxy.management_endpoints.key_management_endpoints import _validate_key_alias_format
         from litellm.proxy._types import ProxyException
-        
+
+        litellm.enable_key_alias_format_validation = True
         invalid_aliases = [
             "",               # empty
             " ",              # whitespace
@@ -6701,9 +6717,10 @@ class TestValidateKeyAliasFormat:
             "  leading",
             "trailing  ",
         ]
-        
+
         for alias in invalid_aliases:
             with pytest.raises(ProxyException) as exc:
                 _validate_key_alias_format(alias)
             assert str(exc.value.code) == "400"
             assert "Invalid key_alias format" in str(exc.value.message)
+        litellm.enable_key_alias_format_validation = False