diff --git a/api/kiwi_vpn_api/routers/_common.py b/api/kiwi_vpn_api/routers/_common.py
index 3b76e30..5c8c4b9 100644
--- a/api/kiwi_vpn_api/routers/_common.py
+++ b/api/kiwi_vpn_api/routers/_common.py
@@ -58,6 +58,10 @@ async def get_current_config(
 ) -> Config:
     """
     Get the current configuration if it exists.
+
+    Status:
+
+    - 400: `kiwi-vpn` not installed
     """
 
     # fail if not configured
@@ -73,6 +77,10 @@ async def get_current_user(
 ) -> User:
     """
     Get the currently logged-in user if it exists.
+
+    Status:
+
+    - 403: invalid auth token, or user not found
     """
 
     # don't use error 404 here - possible user enumeration
@@ -89,23 +97,32 @@ async def get_current_user(
 
 async def get_user_by_name(
     user_name: str,
-    _: Config = Depends(get_current_config),
-) -> User | None:
+) -> User:
     """
     Get a user by name.
+
+    Status:
+
+    - 404: user not found
     """
 
-    return User.get(user_name)
+    # fail if device doesn't exist
+    if (user := User.get(user_name)) is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND)
+
+    return user
 
 
 async def get_device_by_id(
     device_id: int,
-    current_config: Config = Depends(get_current_config),
-) -> Device | None:
+) -> Device:
+    """
+    Get a device by ID.
 
-    # can't connect to an unconfigured database
-    if current_config is None:
-        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST)
+    Status:
+
+    - 404: device not found
+    """
 
     # fail if device doesn't exist
     if (device := Device.get(device_id)) is None:
diff --git a/api/kiwi_vpn_api/routers/device.py b/api/kiwi_vpn_api/routers/device.py
index 44cc144..710de22 100644
--- a/api/kiwi_vpn_api/routers/device.py
+++ b/api/kiwi_vpn_api/routers/device.py
@@ -37,10 +37,6 @@ async def add_device(
     if not current_user.can_create(Device, owner):
         raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)
 
-    # fail if owner doesn't exist
-    if owner is None:
-        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND)
-
     # create the new device
     new_device = Device.create(
         owner=owner,