diff --git a/app/clients/_authenticationclient.py b/app/clients/_authenticationclient.py
index f18ec97..e369d10 100644
--- a/app/clients/_authenticationclient.py
+++ b/app/clients/_authenticationclient.py
@@ -86,7 +86,7 @@ async def check_api_key(self, key: str) -> Optional[User]:
         Returns:
             Optional[User]: User object if found, None otherwise
         """
-        user_id = self._api_key_to_user_id(input=key)
+        user_id = self.api_key_to_user_id(input=key)
         ttl = -2
 
         # fetch from Redis
@@ -121,15 +121,15 @@ async def check_api_key(self, key: str) -> Optional[User]:
                 return user
 
     @staticmethod
-    def _api_key_to_user_id(input: str) -> str:
+    def api_key_to_user_id(input: str) -> str:
         """
-        Generate a 16 length unique code from an input string using salted SHA-256 hashing.
+        Generate a 16 length unique user id from an input string using SHA-256 hashing.
 
         Args:
-            input_string (str): The input string to generate the code from.
+            input_string (str): The input string to generate the user id from.
 
         Returns:
-            tuple[str, bytes]: A tuple containing the generated code and the salt used.
+            str: The generated user id.
         """
         hash = hashlib.sha256((input).encode()).digest()
         hash = base64.urlsafe_b64encode(hash).decode()
diff --git a/app/helpers/_metricsmiddleware.py b/app/helpers/_metricsmiddleware.py
index d4920b4..68ecdb0 100644
--- a/app/helpers/_metricsmiddleware.py
+++ b/app/helpers/_metricsmiddleware.py
@@ -48,7 +48,7 @@ async def dispatch(self, request: Request, call_next) -> Response:
                     )
 
             if authorization and authorization.startswith("Bearer "):
-                user_id = AuthenticationClient._api_key_to_user_id(input=authorization.split(sep=" ")[1])
+                user_id = AuthenticationClient.api_key_to_user_id(input=authorization.split(sep=" ")[1])
                 self.http_requests_by_user.labels(user=user_id, endpoint=endpoint[3:], model=model).inc()
 
         response = await call_next(request)
diff --git a/app/tests/conftest.py b/app/tests/conftest.py
index d9c4fce..7e3edef 100644
--- a/app/tests/conftest.py
+++ b/app/tests/conftest.py
@@ -45,8 +45,8 @@ def session_admin(args):
 
 @pytest.fixture(scope="session")
 def cleanup_collections(args, session_user, session_admin):
-    USER = AuthenticationClient._api_key_to_user_id(input=args["api_key_user"])
-    ADMIN = AuthenticationClient._api_key_to_user_id(input=args["api_key_admin"])
+    USER = AuthenticationClient.api_key_to_user_id(input=args["api_key_user"])
+    ADMIN = AuthenticationClient.api_key_to_user_id(input=args["api_key_admin"])
 
     yield USER, ADMIN
 
diff --git a/app/tests/test_collections.py b/app/tests/test_collections.py
index 4a2f480..3604942 100644
--- a/app/tests/test_collections.py
+++ b/app/tests/test_collections.py
@@ -14,8 +14,8 @@
 
 @pytest.fixture(scope="module")
 def setup(args, session_user):
-    USER = AuthenticationClient._api_key_to_user_id(input=args["api_key_user"])
-    ADMIN = AuthenticationClient._api_key_to_user_id(input=args["api_key_admin"])
+    USER = AuthenticationClient.api_key_to_user_id(input=args["api_key_user"])
+    ADMIN = AuthenticationClient.api_key_to_user_id(input=args["api_key_admin"])
     logging.info(f"test user ID: {USER}")
     logging.info(f"test admin ID: {ADMIN}")
 
diff --git a/app/utils/security.py b/app/utils/security.py
index a3a94be..34a34cf 100644
--- a/app/utils/security.py
+++ b/app/utils/security.py
@@ -3,12 +3,11 @@
 from fastapi import Depends, Request
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 
-from app.schemas.security import User
-from app.utils.settings import settings
-from app.utils.exceptions import InvalidAPIKeyException, InvalidAuthenticationSchemeException, InsufficientRightsException
+from app.clients import AuthenticationClient
+from app.schemas.security import Role, User
+from app.utils.exceptions import InsufficientRightsException, InvalidAPIKeyException, InvalidAuthenticationSchemeException
 from app.utils.lifespan import clients
-from app.schemas.security import Role
-
+from app.utils.settings import settings
 
 if settings.clients.auth:
 
@@ -57,7 +56,7 @@ def check_api_key(api_key: Optional[str] = None) -> User:
         return User(id="no-auth", role=Role.ADMIN)
 
 
-async def check_rate_limit(request: Request) -> Optional[str]:
+def check_rate_limit(request: Request) -> Optional[str]:
     """
     Check the rate limit for the user.
 
@@ -71,9 +70,6 @@ async def check_rate_limit(request: Request) -> Optional[str]:
     authorization = request.headers.get("Authorization")
     scheme, credentials = authorization.split(" ") if authorization else ("", "")
     api_key = HTTPAuthorizationCredentials(scheme=scheme, credentials=credentials)
-    user = await check_api_key(api_key=api_key)
+    user_id = AuthenticationClient.api_key_to_user_id(input=api_key.credentials)
 
-    if user.role.value > Role.USER.value:
-        return None
-    else:
-        return user.id
+    return user_id