diff --git a/pyoverkiz/_case.py b/pyoverkiz/_case.py
index f87448b7..2170989f 100644
--- a/pyoverkiz/_case.py
+++ b/pyoverkiz/_case.py
@@ -4,8 +4,10 @@
 
 import functools
 import re
-from collections.abc import Callable
-from typing import Any
+from typing import TYPE_CHECKING, Any
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
 
 _CAMEL_RE = re.compile(r"([A-Z]+)([A-Z][a-z])|([a-z\d])([A-Z])")
 
diff --git a/pyoverkiz/action_queue.py b/pyoverkiz/action_queue.py
index 104809a8..2b5e3523 100644
--- a/pyoverkiz/action_queue.py
+++ b/pyoverkiz/action_queue.py
@@ -4,13 +4,14 @@
 
 import asyncio
 import contextlib
-from collections.abc import Callable, Coroutine, Generator
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any
 
 from pyoverkiz.models import Action
 
 if TYPE_CHECKING:
+    from collections.abc import Callable, Coroutine, Generator
+
     from pyoverkiz.enums import ExecutionMode
 
 
diff --git a/pyoverkiz/auth/base.py b/pyoverkiz/auth/base.py
index e10b99ca..bdf2a490 100644
--- a/pyoverkiz/auth/base.py
+++ b/pyoverkiz/auth/base.py
@@ -3,9 +3,11 @@
 from __future__ import annotations
 
 import datetime
-from collections.abc import Mapping
 from dataclasses import dataclass
-from typing import Any, Protocol
+from typing import TYPE_CHECKING, Any, Protocol
+
+if TYPE_CHECKING:
+    from collections.abc import Mapping
 
 
 @dataclass(slots=True)
diff --git a/pyoverkiz/auth/factory.py b/pyoverkiz/auth/factory.py
index 4ee91425..0e677e7b 100644
--- a/pyoverkiz/auth/factory.py
+++ b/pyoverkiz/auth/factory.py
@@ -2,9 +2,7 @@
 
 from __future__ import annotations
 
-import ssl
-
-from aiohttp import ClientSession
+from typing import TYPE_CHECKING
 
 from pyoverkiz.auth.credentials import (
     Credentials,
@@ -24,7 +22,13 @@
     SomfyAuthStrategy,
 )
 from pyoverkiz.enums import APIType, Server
-from pyoverkiz.models import ServerConfig
+
+if TYPE_CHECKING:
+    import ssl
+
+    from aiohttp import ClientSession
+
+    from pyoverkiz.models import ServerConfig
 
 
 def build_auth_strategy(
diff --git a/pyoverkiz/auth/strategies.py b/pyoverkiz/auth/strategies.py
index b5a0e3c7..0d44203c 100644
--- a/pyoverkiz/auth/strategies.py
+++ b/pyoverkiz/auth/strategies.py
@@ -6,23 +6,26 @@
 import base64
 import binascii
 import json
-import ssl
-from collections.abc import Mapping
 from http import HTTPStatus
 from typing import TYPE_CHECKING, Any, cast
 
 if TYPE_CHECKING:
+    import ssl
+    from collections.abc import Mapping
+
     from botocore.client import BaseClient
 
+    from pyoverkiz.auth.credentials import (
+        LocalTokenCredentials,
+        RexelOAuthCodeCredentials,
+        TokenCredentials,
+        UsernamePasswordCredentials,
+    )
+    from pyoverkiz.models import ServerConfig
+
 from aiohttp import ClientSession, FormData
 
 from pyoverkiz.auth.base import AuthContext, AuthStrategy
-from pyoverkiz.auth.credentials import (
-    LocalTokenCredentials,
-    RexelOAuthCodeCredentials,
-    TokenCredentials,
-    UsernamePasswordCredentials,
-)
 from pyoverkiz.const import (
     COZYTOUCH_ATLANTIC_API,
     COZYTOUCH_CLIENT_ID,
@@ -48,7 +51,6 @@
     SomfyBadCredentialsError,
     SomfyServiceError,
 )
-from pyoverkiz.models import ServerConfig
 
 MIN_JWT_SEGMENTS = 2
 
@@ -159,7 +161,7 @@ async def refresh_if_needed(self) -> bool:
 
         await self._request_access_token(
             grant_type="refresh_token",
-            extra_fields={"refresh_token": cast(str, self.context.refresh_token)},
+            extra_fields={"refresh_token": cast("str", self.context.refresh_token)},
         )
         return True
 
@@ -351,7 +353,7 @@ async def refresh_if_needed(self) -> bool:
                 "grant_type": "refresh_token",
                 "client_id": REXEL_OAUTH_CLIENT_ID,
                 "scope": REXEL_OAUTH_SCOPE,
-                "refresh_token": cast(str, self.context.refresh_token),
+                "refresh_token": cast("str", self.context.refresh_token),
             }
         )
         return True
@@ -429,6 +431,6 @@ def _decode_jwt_payload(token: str) -> dict[str, Any]:
     padding = "=" * (-len(payload_segment) % 4)
     try:
         decoded = base64.urlsafe_b64decode(payload_segment + padding)
-        return cast(dict[str, Any], json.loads(decoded))
+        return cast("dict[str, Any]", json.loads(decoded))
     except (binascii.Error, json.JSONDecodeError) as error:
         raise InvalidTokenError("Malformed JWT received.") from error
diff --git a/pyoverkiz/client.py b/pyoverkiz/client.py
index 38d8dbba..c5b597d4 100644
--- a/pyoverkiz/client.py
+++ b/pyoverkiz/client.py
@@ -7,8 +7,7 @@
 import urllib.parse
 from http import HTTPStatus
 from pathlib import Path
-from types import TracebackType
-from typing import Any, Self, cast
+from typing import TYPE_CHECKING, Any, Self, cast
 
 import backoff
 from aiohttp import (
@@ -17,7 +16,6 @@
     ClientSession,
     ServerDisconnectedError,
 )
-from backoff.types import Details
 
 from pyoverkiz._case import decamelize
 from pyoverkiz.action_queue import ActionQueue, ActionQueueSettings
@@ -55,14 +53,20 @@
 from pyoverkiz.obfuscate import obfuscate_sensitive_data
 from pyoverkiz.response_handler import check_response
 from pyoverkiz.serializers import prepare_payload
-from pyoverkiz.types import JSON
+
+if TYPE_CHECKING:
+    from types import TracebackType
+
+    from backoff.types import Details
+
+    from pyoverkiz.types import JSON
 
 _LOGGER = logging.getLogger(__name__)
 
 
 def _get_client_from_invocation(invocation: Details) -> OverkizClient:
     """Return the `OverkizClient` instance from a backoff invocation."""
-    return cast(OverkizClient, invocation["args"][0])
+    return cast("OverkizClient", invocation["args"][0])
 
 
 async def relogin(invocation: Details) -> None:
@@ -419,7 +423,7 @@ async def register_event_listener(self) -> str:
         API on a regular basis.
         """
         response = await self._post("events/register")
-        listener_id = cast(str, response.get("id"))
+        listener_id = cast("str", response.get("id"))
         self.event_listener_id = listener_id
 
         return listener_id
@@ -472,7 +476,7 @@ async def get_api_version(self) -> str:
         """Get the API version (local only)."""
         response = await self._get("apiVersion")
 
-        return cast(str, response["protocolVersion"])
+        return cast("str", response["protocolVersion"])
 
     @retry_on_too_many_executions
     @retry_on_auth_error
@@ -492,7 +496,7 @@ async def _execute_action_group_direct(
 
         response: dict = await self._post(url, prepare_payload(payload))
 
-        return cast(str, response["execId"])
+        return cast("str", response["execId"])
 
     async def execute_action_group(
         self,
@@ -578,13 +582,13 @@ async def get_places(self) -> Place:
     async def execute_persisted_action_group(self, oid: str) -> str:
         """Execute a server-side action group by its OID (see ``get_action_groups``)."""
         response = await self._post(f"exec/{oid}")
-        return cast(str, response["execId"])
+        return cast("str", response["execId"])
 
     @retry_on_auth_error
     async def schedule_persisted_action_group(self, oid: str, timestamp: int) -> str:
         """Schedule a server-side action group for execution at the given timestamp."""
         response = await self._post(f"exec/schedule/{oid}/{timestamp}")
-        return cast(str, response["triggerId"])
+        return cast("str", response["triggerId"])
 
     @retry_on_auth_error
     async def get_setup_options(self) -> list[Option]:
diff --git a/pyoverkiz/enums/base.py b/pyoverkiz/enums/base.py
index 83c075bc..8ce8dd35 100644
--- a/pyoverkiz/enums/base.py
+++ b/pyoverkiz/enums/base.py
@@ -36,4 +36,4 @@ def _missing_(cls, value: object) -> Self:  # type: ignore[override]
         message = cls.__missing_message__
         logging.getLogger(cls.__module__).warning(message, value, cls)
         # Type checker cannot infer UNKNOWN exists on Self, but all subclasses define it
-        return cast(Self, cls.UNKNOWN)  # type: ignore[attr-defined]
+        return cast("Self", cls.UNKNOWN)  # type: ignore[attr-defined]
diff --git a/pyoverkiz/models.py b/pyoverkiz/models.py
index 411ec73d..6faab4ac 100644
--- a/pyoverkiz/models.py
+++ b/pyoverkiz/models.py
@@ -5,8 +5,7 @@
 import json
 import logging
 import re
-from collections.abc import Iterator
-from typing import Any, cast
+from typing import TYPE_CHECKING, Any, cast
 
 from attr import define, field
 
@@ -24,12 +23,16 @@
     UIWidget,
     UpdateBoxStatus,
 )
-from pyoverkiz.enums.command import OverkizCommand, OverkizCommandParam
 from pyoverkiz.enums.protocol import Protocol
 from pyoverkiz.enums.server import APIType, Server
 from pyoverkiz.obfuscate import obfuscate_email, obfuscate_id, obfuscate_string
 from pyoverkiz.types import DATA_TYPE_TO_PYTHON, StateType
 
+if TYPE_CHECKING:
+    from collections.abc import Iterator
+
+    from pyoverkiz.enums.command import OverkizCommand, OverkizCommandParam
+
 # pylint: disable=unused-argument, too-many-instance-attributes, too-many-locals
 
 # <protocol>://<gatewayId>/<deviceAddress>[#<subsystemId>]
@@ -527,7 +530,7 @@ def value_as_int(self) -> int | None:
         if self.type == DataType.NONE:
             return None
         if self.type == DataType.INTEGER:
-            return cast(int, self.value)
+            return cast("int", self.value)
         raise TypeError(f"{self.name} is not an integer")
 
     @property
@@ -536,9 +539,9 @@ def value_as_float(self) -> float | None:
         if self.type == DataType.NONE:
             return None
         if self.type == DataType.FLOAT:
-            return cast(float, self.value)
+            return cast("float", self.value)
         if self.type == DataType.INTEGER:
-            return float(cast(int, self.value))
+            return float(cast("int", self.value))
         raise TypeError(f"{self.name} is not a float")
 
     @property
@@ -547,7 +550,7 @@ def value_as_bool(self) -> bool | None:
         if self.type == DataType.NONE:
             return None
         if self.type == DataType.BOOLEAN:
-            return cast(bool, self.value)
+            return cast("bool", self.value)
         raise TypeError(f"{self.name} is not a boolean")
 
     @property
@@ -556,7 +559,7 @@ def value_as_str(self) -> str | None:
         if self.type == DataType.NONE:
             return None
         if self.type == DataType.STRING:
-            return cast(str, self.value)
+            return cast("str", self.value)
         raise TypeError(f"{self.name} is not a string")
 
     @property
@@ -565,7 +568,7 @@ def value_as_dict(self) -> dict[str, Any] | None:
         if self.type == DataType.NONE:
             return None
         if self.type == DataType.JSON_OBJECT:
-            return cast(dict, self.value)
+            return cast("dict", self.value)
         raise TypeError(f"{self.name} is not a JSON object")
 
     @property
@@ -574,7 +577,7 @@ def value_as_list(self) -> list[Any] | None:
         if self.type == DataType.NONE:
             return None
         if self.type == DataType.JSON_ARRAY:
-            return cast(list, self.value)
+            return cast("list", self.value)
         raise TypeError(f"{self.name} is not an array")
 
 
@@ -899,7 +902,10 @@ def __init__(
         **_: Any,
     ) -> None:
         """Initialize ActionGroup from API data and convert nested actions."""
-        self.id = oid or id
+        if oid is None and id is None:
+            raise ValueError("Either 'oid' or 'id' must be provided")
+
+        self.id = cast("str", oid or id)
         self.creation_time = creation_time
         self.last_update_time = last_update_time
         self.label = (
@@ -912,7 +918,7 @@ def __init__(
         self.notification_text = notification_text
         self.notification_title = notification_title
         self.actions = [Action(**action) for action in actions]
-        self.oid = oid or id
+        self.oid = cast("str", oid or id)
 
 
 @define(init=False, kw_only=True)
@@ -1421,7 +1427,12 @@ def __init__(
 
 @define(kw_only=True)
 class FirmwareStatus:
-    """Firmware status of a device."""
+    """
+    Firmware status of a device.
+
+    `up_to_date` indicates whether the current firmware is the latest available
+    version and `notes` contains provider messages about the firmware state.
+    """
 
     up_to_date: bool
     notes: list[dict[str, str]]
diff --git a/pyoverkiz/obfuscate.py b/pyoverkiz/obfuscate.py
index ca26abd6..0831bad8 100644
--- a/pyoverkiz/obfuscate.py
+++ b/pyoverkiz/obfuscate.py
@@ -3,9 +3,10 @@
 from __future__ import annotations
 
 import re
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
-from pyoverkiz.types import JSON
+if TYPE_CHECKING:
+    from pyoverkiz.types import JSON
 
 
 def obfuscate_id(id: str | None) -> str:
diff --git a/pyoverkiz/response_handler.py b/pyoverkiz/response_handler.py
index dbeb918c..66ea0952 100644
--- a/pyoverkiz/response_handler.py
+++ b/pyoverkiz/response_handler.py
@@ -4,8 +4,7 @@
 
 from http import HTTPStatus
 from json import JSONDecodeError
-
-from aiohttp import ClientResponse
+from typing import TYPE_CHECKING
 
 from pyoverkiz.exceptions import (
     AccessDeniedToGatewayError,
@@ -40,6 +39,9 @@
     UnsupportedOperationError,
 )
 
+if TYPE_CHECKING:
+    from aiohttp import ClientResponse
+
 # Primary dispatch: (errorCode, message_substring) -> error class.
 # Checked in order; first match wins. Use errorCode as the primary key to
 # reduce brittleness across cloud vs. local API variants.
diff --git a/pyoverkiz/types.py b/pyoverkiz/types.py
index 167f5951..fdd47498 100644
--- a/pyoverkiz/types.py
+++ b/pyoverkiz/types.py
@@ -3,11 +3,13 @@
 from __future__ import annotations
 
 import json
-from collections.abc import Callable
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 from pyoverkiz.enums import DataType
 
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
 StateType = str | int | float | bool | dict[str, Any] | list[Any] | None
 
 
diff --git a/pyproject.toml b/pyproject.toml
index f97104c5..d3478598 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -124,6 +124,8 @@ select = [
     "A",
     # pylint
     "PL",
+    # flake8-type-checking
+    "TC",
 ]
 ignore = [
     "E501",    # Line too long
@@ -132,6 +134,7 @@ ignore = [
     "PLR0913", # Too many arguments — expected for API model constructors
     "PLC0415", # Import not at top level — intentional lazy imports
     "PLR0911", # Too many return statements — acceptable in factory functions
+    "TC006",   # Quoting cast() types hurts IDE autocomplete for no real benefit
 ]
 
 [tool.ruff.lint.per-file-ignores]
diff --git a/tests/test_client.py b/tests/test_client.py
index 17bbbb9b..97084580 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -725,7 +725,7 @@ async def test_get_current_execution_returns_none_for_empty_response(
         client: OverkizClient,
         fixture_name: str,
     ):
-        """Cloud returns {} and local returns [] for non-existent exec_ids."""
+        """Cloud returns {} and local returns [] for non-existent exec_id."""
         with (CURRENT_DIR / "fixtures" / "endpoints" / fixture_name).open(
             encoding="utf-8",
         ) as f:
diff --git a/utils/generate_enums.py b/utils/generate_enums.py
index 3b88d9be..b8f039a3 100644
--- a/utils/generate_enums.py
+++ b/utils/generate_enums.py
@@ -12,13 +12,15 @@
 import re
 import subprocess
 from pathlib import Path
-from typing import cast
+from typing import TYPE_CHECKING, cast
 
 from pyoverkiz.auth.credentials import UsernamePasswordCredentials
 from pyoverkiz.client import OverkizClient
 from pyoverkiz.enums import Server
 from pyoverkiz.exceptions import OverkizError
-from pyoverkiz.models import UIProfileDefinition, ValuePrototype
+
+if TYPE_CHECKING:
+    from pyoverkiz.models import UIProfileDefinition, ValuePrototype
 
 # Hardcoded protocols that may not be available on all servers
 # Each tuple contains: name, prefix, id, label
@@ -129,8 +131,8 @@ async def generate_ui_enums(server: Server) -> None:
     ) as client:
         await client.login()
 
-        ui_classes = cast(list[str], await client.get_reference_ui_classes())
-        ui_widgets = cast(list[str], await client.get_reference_ui_widgets())
+        ui_classes = cast("list[str]", await client.get_reference_ui_classes())
+        ui_widgets = cast("list[str]", await client.get_reference_ui_widgets())
 
         # Convert camelCase to SCREAMING_SNAKE_CASE for enum names
         def to_enum_name(value: str) -> str:
@@ -210,7 +212,7 @@ def to_enum_name(value: str) -> str:
         lines.append("")  # End with newline
 
         # Fetch and add UI classifiers
-        ui_classifiers = cast(list[str], await client.get_reference_ui_classifiers())
+        ui_classifiers = cast("list[str]", await client.get_reference_ui_classifiers())
 
         lines.append("")
         lines.append("@unique")