diff --git a/cinder/api/api_utils.py b/cinder/api/api_utils.py
index 05a1c7a07c2..606dba692da 100644
--- a/cinder/api/api_utils.py
+++ b/cinder/api/api_utils.py
@@ -10,6 +10,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from __future__ import annotations
+
+import typing
+from typing import Any, Generator, Iterable, Optional, Union  # noqa: H301
+
 from keystoneauth1 import exceptions as ks_exc
 from keystoneauth1 import identity
 from keystoneauth1 import loading as ka_loading
@@ -20,6 +25,9 @@ from oslo_utils import strutils
 import webob
 from webob import exc
 
+if typing.TYPE_CHECKING:
+    # conditional import to avoid a circular import problem from cinderlib
+    from cinder import context
 from cinder import exception
 from cinder.i18n import _
 
@@ -30,7 +38,7 @@ CONF.import_group('keystone_authtoken',
 LOG = logging.getLogger(__name__)
 
 
-def _parse_is_public(is_public):
+def _parse_is_public(is_public: Optional[str]) -> Optional[bool]:
     """Parse is_public into something usable.
 
     * True: List public volume types only
@@ -51,7 +59,7 @@ def _parse_is_public(is_public):
             raise exc.HTTPBadRequest(explanation=msg)
 
 
-def is_none_string(val):
+def is_none_string(val: Any) -> bool:
     """Check if a string represents a None value."""
     if not isinstance(val, str):
         return False
@@ -59,8 +67,10 @@ def is_none_string(val):
     return val.lower() == 'none'
 
 
-def remove_invalid_filter_options(context, filters,
-                                  allowed_search_options):
+def remove_invalid_filter_options(
+        context: 'context.RequestContext',
+        filters: dict,
+        allowed_search_options: Iterable[str]) -> None:
     """Remove search options that are not valid for non-admin API/context."""
 
     if context.is_admin:
@@ -78,7 +88,7 @@ def remove_invalid_filter_options(context, filters,
 _visible_admin_metadata_keys = ['readonly', 'attached_mode']
 
 
-def add_visible_admin_metadata(volume):
+def add_visible_admin_metadata(volume) -> None:
     """Add user-visible admin metadata to regular metadata.
 
     Extracts the admin metadata keys that are to be made visible to
@@ -125,13 +135,15 @@ def add_visible_admin_metadata(volume):
         volume['metadata'] = visible_admin_meta
 
 
-def validate_integer(value, name, min_value=None, max_value=None):
+def validate_integer(value: int, name: str,
+                     min_value: Optional[int] = None,
+                     max_value: Optional[int] = None) -> int:
     """Make sure that value is a valid integer, potentially within range.
 
     :param value: the value of the integer
     :param name: the name of the integer
-    :param min_length: the min_length of the integer
-    :param max_length: the max_length of the integer
+    :param min_value: the min value of the integer
+    :param max_value: the max value of the integer
     :returns: integer
     """
     try:
@@ -141,7 +153,9 @@ def validate_integer(value, name, min_value=None, max_value=None):
         raise webob.exc.HTTPBadRequest(explanation=str(e))
 
 
-def walk_class_hierarchy(clazz, encountered=None):
+def walk_class_hierarchy(clazz: type,
+                         encountered: Optional[list[type]] = None) -> \
+        Generator[type, None, None]:
     """Walk class hierarchy, yielding most derived classes first."""
     if not encountered:
         encountered = []
@@ -154,7 +168,8 @@ def walk_class_hierarchy(clazz, encountered=None):
             yield subclass
 
 
-def _keystone_client(context, version=(3, 0)):
+def _keystone_client(context: 'context.RequestContext',
+                     version: tuple[int, int] = (3, 0)) -> client.Client:
     """Creates and returns an instance of a generic keystone client.
 
     :param context: The request context
@@ -199,8 +214,12 @@ def _keystone_client(context, version=(3, 0)):
 
 class GenericProjectInfo(object):
     """Abstraction layer for Keystone V2 and V3 project objects"""
-    def __init__(self, project_id, project_keystone_api_version,
-                 domain_id=None, name=None, description=None):
+    def __init__(self,
+                 project_id: str,
+                 project_keystone_api_version: str,
+                 domain_id: Optional[str] = None,
+                 name: Optional[str] = None,
+                 description: Optional[str] = None):
         self.id = project_id
         self.keystone_api_version = project_keystone_api_version
         self.domain_id = domain_id
@@ -208,7 +227,8 @@ class GenericProjectInfo(object):
         self.description = description
 
 
-def get_project(context, project_id):
+def get_project(context: 'context.RequestContext',
+                project_id: str) -> GenericProjectInfo:
     """Method to verify project exists in keystone"""
     keystone = _keystone_client(context)
     generic_project = GenericProjectInfo(project_id, keystone.version)
@@ -219,8 +239,11 @@ def get_project(context, project_id):
     return generic_project
 
 
-def validate_project_and_authorize(context, project_id, policy_check=None,
-                                   validate_only=False):
+def validate_project_and_authorize(context: 'context.RequestContext',
+                                   project_id: str,
+                                   policy_check: str,
+                                   validate_only: bool = False) -> None:
+    target_project: Union[GenericProjectInfo, dict]
     try:
         target_project = get_project(context, project_id)
         if not validate_only:
diff --git a/mypy-files.txt b/mypy-files.txt
index 5edf565e8e9..7ad4be87386 100644
--- a/mypy-files.txt
+++ b/mypy-files.txt
@@ -1,3 +1,4 @@
+cinder/api/api_utils.py
 cinder/api/v3/types.py
 cinder/backup/api.py
 cinder/backup/manager.py