diff --git a/keyring/backend.py b/keyring/backend.py
index 1b903587..a1c2a9f3 100644
--- a/keyring/backend.py
+++ b/keyring/backend.py
@@ -1,6 +1,7 @@
 """
 Keyring implementation support
 """
+from __future__ import annotations
 
 import os
 import abc
@@ -8,7 +9,7 @@
 import operator
 import copy
 
-from typing import Optional
+import typing
 
 from .py312compat import metadata
 from . import credentials, errors, util
@@ -18,7 +19,7 @@
 
 
 by_priority = operator.attrgetter('priority')
-_limit = None
+_limit: typing.Optional[typing.Callable[[KeyringBackend], bool]] = None
 
 
 class KeyringBackendMeta(abc.ABCMeta):
@@ -44,8 +45,8 @@ class KeyringBackend(metaclass=KeyringBackendMeta):
     def __init__(self):
         self.set_properties_from_env()
 
-    # @abc.abstractproperty
-    def priority(cls):
+    @properties.classproperty
+    def priority(self) -> typing.Union[int, float]:
         """
         Each backend class must supply a priority, a number (float or integer)
         indicating the priority of the backend relative to all other backends.
@@ -60,6 +61,7 @@ def priority(cls):
         As a rule of thumb, a priority between zero but less than one is
         suitable, but a priority of one or greater is recommended.
         """
+        raise NotImplementedError
 
     @properties.classproperty
     def viable(cls):
@@ -68,14 +70,16 @@ def viable(cls):
         return not exc
 
     @classmethod
-    def get_viable_backends(cls):
+    def get_viable_backends(
+        cls: typing.Type[KeyringBackend],
+    ) -> filter[typing.Type[KeyringBackend]]:
         """
         Return all subclasses deemed viable.
         """
         return filter(operator.attrgetter('viable'), cls._classes)
 
     @properties.classproperty
-    def name(cls):
+    def name(cls) -> str:
         """
         The keyring name, suitable for display.
 
@@ -83,16 +87,16 @@ def name(cls):
         """
         parent, sep, mod_name = cls.__module__.rpartition('.')
         mod_name = mod_name.replace('_', ' ')
-        return ' '.join([mod_name, cls.__name__])
+        return ' '.join([mod_name, cls.__name__])  # type: ignore
 
-    def __str__(self):
+    def __str__(self) -> str:
         keyring_class = type(self)
         return "{}.{} (priority: {:g})".format(
             keyring_class.__module__, keyring_class.__name__, keyring_class.priority
         )
 
     @abc.abstractmethod
-    def get_password(self, service: str, username: str) -> Optional[str]:
+    def get_password(self, service: str, username: str) -> typing.Optional[str]:
         """Get password of the username for the service"""
         return None
 
@@ -122,8 +126,8 @@ def delete_password(self, service: str, username: str) -> None:
     def get_credential(
         self,
         service: str,
-        username: Optional[str],
-    ) -> Optional[credentials.Credential]:
+        username: typing.Optional[str],
+    ) -> typing.Optional[credentials.Credential]:
         """Gets the username and password for the service.
         Returns a Credential instance.
 
@@ -138,19 +142,21 @@ def get_credential(
                 return credentials.SimpleCredential(username, password)
         return None
 
-    def set_properties_from_env(self):
+    def set_properties_from_env(self) -> None:
         """For all KEYRING_PROPERTY_* env var, set that property."""
 
-        def parse(item):
+        def parse(item: typing.Tuple[str, str]):
             key, value = item
             pre, sep, name = key.partition('KEYRING_PROPERTY_')
             return sep and (name.lower(), value)
 
-        props = filter(None, map(parse, os.environ.items()))
+        props: filter[typing.Tuple[str, str]] = filter(
+            None, map(parse, os.environ.items())
+        )
         for name, value in props:
             setattr(self, name, value)
 
-    def with_properties(self, **kwargs):
+    def with_properties(self, **kwargs: typing.Any) -> KeyringBackend:
         alt = copy.copy(self)
         vars(alt).update(kwargs)
         return alt
@@ -180,7 +186,7 @@ def decrypt(self, value):
         return value
 
 
-def _load_plugins():
+def _load_plugins() -> None:
     """
     Locate all setuptools entry points by the name 'keyring backends'
     and initialize them.
@@ -207,7 +213,7 @@ def _load_plugins():
 
 
 @util.once
-def get_all_keyring():
+def get_all_keyring() -> typing.List[KeyringBackend]:
     """
     Return a list of all implemented keyrings that can be constructed without
     parameters.
@@ -241,7 +247,9 @@ class SchemeSelectable:
         KeePassXC=dict(username='UserName', service='Title'),
     )
 
-    def _query(self, service, username=None, **base):
+    def _query(
+        self, service: str, username: typing.Optional[str] = None, **base: typing.Any
+    ) -> typing.Dict[str, str]:
         scheme = self.schemes[self.scheme]
         return dict(
             {
diff --git a/keyring/backends/SecretService.py b/keyring/backends/SecretService.py
index 7edb238d..bcd67165 100644
--- a/keyring/backends/SecretService.py
+++ b/keyring/backends/SecretService.py
@@ -30,7 +30,7 @@ class Keyring(backend.SchemeSelectable, KeyringBackend):
     appid = 'Python keyring library'
 
     @properties.classproperty
-    def priority(cls):
+    def priority(cls) -> int:
         with ExceptionRaisedContext() as exc:
             secretstorage.__name__
         if exc:
diff --git a/keyring/backends/Windows.py b/keyring/backends/Windows.py
index a686d895..962c9a9a 100644
--- a/keyring/backends/Windows.py
+++ b/keyring/backends/Windows.py
@@ -81,7 +81,7 @@ class WinVaultKeyring(KeyringBackend):
     persist = Persistence()
 
     @properties.classproperty
-    def priority(cls):
+    def priority(cls) -> int:
         """
         If available, the preferred backend on Windows.
         """
diff --git a/keyring/backends/chainer.py b/keyring/backends/chainer.py
index 5a9281c7..42da1f0f 100644
--- a/keyring/backends/chainer.py
+++ b/keyring/backends/chainer.py
@@ -2,7 +2,6 @@
 Keyring Chainer - iterates over other viable backends to
 discover passwords in each.
 """
-
 from .. import backend
 from .._compat import properties
 from . import fail
@@ -19,7 +18,7 @@ class ChainerBackend(backend.KeyringBackend):
     viable = True
 
     @properties.classproperty
-    def priority(cls):
+    def priority(cls) -> int:
         """
         If there are backends to chain, high priority
         Otherwise very low priority since our operation when empty
diff --git a/keyring/backends/fail.py b/keyring/backends/fail.py
index 179717a9..9bcdfc80 100644
--- a/keyring/backends/fail.py
+++ b/keyring/backends/fail.py
@@ -1,4 +1,5 @@
 from ..backend import KeyringBackend
+from .._compat import properties
 from ..errors import NoKeyringError
 
 
@@ -13,7 +14,9 @@ class Keyring(KeyringBackend):
     keyring.errors.NoKeyringError: ...No recommended backend...
     """
 
-    priority = 0
+    @properties.classproperty
+    def priority(cls) -> int:
+        return 0
 
     def get_password(self, service, username, password=None):
         msg = (
diff --git a/keyring/backends/kwallet.py b/keyring/backends/kwallet.py
index 3137daed..9decb36c 100644
--- a/keyring/backends/kwallet.py
+++ b/keyring/backends/kwallet.py
@@ -38,7 +38,7 @@ class DBusKeyring(KeyringBackend):
     object_path = '/modules/kwalletd5'
 
     @properties.classproperty
-    def priority(cls):
+    def priority(cls) -> float:
         if 'dbus' not in globals():
             raise RuntimeError('python-dbus not installed')
         try:
diff --git a/keyring/backends/libsecret.py b/keyring/backends/libsecret.py
index cf16dbec..5bc4f076 100644
--- a/keyring/backends/libsecret.py
+++ b/keyring/backends/libsecret.py
@@ -48,7 +48,7 @@ def collection(self):
         return Secret.COLLECTION_DEFAULT
 
     @properties.classproperty
-    def priority(cls):
+    def priority(cls) -> float:
         if not available:
             raise RuntimeError("libsecret required")
 
diff --git a/keyring/backends/null.py b/keyring/backends/null.py
index 6525c0ff..c2067b73 100644
--- a/keyring/backends/null.py
+++ b/keyring/backends/null.py
@@ -1,4 +1,5 @@
 from ..backend import KeyringBackend
+from .._compat import properties
 
 
 class Keyring(KeyringBackend):
@@ -9,7 +10,9 @@ class Keyring(KeyringBackend):
     >>> kr.get_password('svc', 'user')
     """
 
-    priority = -1
+    @properties.classproperty
+    def priority(cls) -> int:
+        return -1
 
     def get_password(self, service, username, password=None):
         pass
diff --git a/keyring/core.py b/keyring/core.py
index 38ca1f08..6ed119f7 100644
--- a/keyring/core.py
+++ b/keyring/core.py
@@ -12,13 +12,14 @@
 from .util import platform_ as platform
 from .backends import fail
 
+LimitCallable = typing.Callable[[backend.KeyringBackend], bool]
 
 log = logging.getLogger(__name__)
 
 _keyring_backend = None
 
 
-def set_keyring(keyring):
+def set_keyring(keyring: backend.KeyringBackend) -> None:
     """Set current keyring backend."""
     global _keyring_backend
     if not isinstance(keyring, backend.KeyringBackend):
@@ -33,7 +34,7 @@ def get_keyring() -> backend.KeyringBackend:
     return typing.cast(backend.KeyringBackend, _keyring_backend)
 
 
-def disable():
+def disable() -> None:
     """
     Configure the null keyring as the default.
     """
@@ -72,18 +73,18 @@ def get_credential(
     return get_keyring().get_credential(service_name, username)
 
 
-def recommended(backend):
+def recommended(backend) -> bool:
     return backend.priority >= 1
 
 
-def init_backend(limit=None):
+def init_backend(limit: typing.Optional[LimitCallable] = None):
     """
     Load a detected backend.
     """
     set_keyring(_detect_backend(limit))
 
 
-def _detect_backend(limit=None):
+def _detect_backend(limit: typing.Optional[LimitCallable] = None):
     """
     Return a keyring specified in the config file or infer the best available.
 
@@ -105,7 +106,7 @@ def _detect_backend(limit=None):
     )
 
 
-def _load_keyring_class(keyring_name):
+def _load_keyring_class(keyring_name: str) -> typing.Type[backend.KeyringBackend]:
     """
     Load the keyring class indicated by name.
 
@@ -126,7 +127,7 @@ def _load_keyring_class(keyring_name):
     return getattr(module, class_name)
 
 
-def load_keyring(keyring_name):
+def load_keyring(keyring_name: str) -> backend.KeyringBackend:
     """
     Load the specified keyring by name (a fully-qualified name to the
     keyring, such as 'keyring.backends.file.PlaintextKeyring')
@@ -137,15 +138,15 @@ def load_keyring(keyring_name):
     return class_()
 
 
-def load_env():
+def load_env() -> typing.Optional[backend.KeyringBackend]:
     """Load a keyring configured in the environment variable."""
     try:
         return load_keyring(os.environ['PYTHON_KEYRING_BACKEND'])
     except KeyError:
-        pass
+        return None
 
 
-def load_config():
+def load_config() -> typing.Optional[backend.KeyringBackend]:
     """Load a keyring using the config file in the config root."""
 
     filename = 'keyringrc.cfg'
@@ -153,7 +154,7 @@ def load_config():
     keyring_cfg = os.path.join(platform.config_root(), filename)
 
     if not os.path.exists(keyring_cfg):
-        return
+        return None
 
     config = configparser.RawConfigParser()
     config.read(keyring_cfg)
@@ -172,12 +173,12 @@ def load_config():
             "Keyring config file contains incorrect values.\n"
             + "Config file: %s" % keyring_cfg
         )
-        return
+        return None
 
     return load_keyring(keyring_name)
 
 
-def _load_keyring_path(config):
+def _load_keyring_path(config: configparser.RawConfigParser) -> None:
     "load the keyring-path option (if present)"
     try:
         path = config.get("backend", "keyring-path").strip()