diff --git a/inertia/helpers.py b/inertia/helpers.py
index 2b5b6c2..919cc59 100644
--- a/inertia/helpers.py
+++ b/inertia/helpers.py
@@ -1,9 +1,17 @@
-from typing import Any
+from __future__ import annotations
 
+from typing import TYPE_CHECKING, cast
 
-def deep_transform_callables(prop: Any) -> Any:
+if TYPE_CHECKING:
+    from collections.abc import Callable
+    from typing import Any, TypeVar
+
+    T = TypeVar("T", bound=Any)
+
+
+def deep_transform_callables(prop: T | Callable[[], T]) -> T:
     if not isinstance(prop, dict):
-        return prop() if callable(prop) else prop
+        return cast("T", prop() if callable(prop) else prop)
 
     for key in list(prop.keys()):
         prop[key] = deep_transform_callables(prop[key])
diff --git a/inertia/http.py b/inertia/http.py
index 433c80c..5f0cfe0 100644
--- a/inertia/http.py
+++ b/inertia/http.py
@@ -1,8 +1,10 @@
+from __future__ import annotations
+
 import logging
 from functools import wraps
 from http import HTTPStatus
 from json import dumps as json_encode
-from typing import Any, Callable
+from typing import TYPE_CHECKING
 
 from django.core.exceptions import ImproperlyConfigured
 from django.http import HttpRequest, HttpResponse
@@ -19,6 +21,25 @@
 except ImportError:
     requests = None  # type: ignore[assignment]
 
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+    from typing import Any, Concatenate, NotRequired, ParamSpec, TypedDict, TypeVar
+
+    P = ParamSpec("P")
+    R = TypeVar("R", HttpResponse, "InertiaResponse", dict[str, Any])
+
+    class PageDataDict(TypedDict):
+        component: str
+        props: dict[str, Any]
+        url: str
+        version: str
+        encryptHistory: bool
+        clearHistory: bool
+        deferredProps: NotRequired[dict[str, Any] | None]
+        mergeProps: NotRequired[list[str]]
+
+
 logger = logging.getLogger(__name__)
 
 INERTIA_REQUEST_ENCRYPT_HISTORY = "_inertia_encrypt_history"
@@ -29,7 +50,7 @@
 
 
 class InertiaRequest(HttpRequest):
-    def __init__(self, request: HttpRequest):
+    def __init__(self, request: HttpRequest) -> None:
         super().__init__()
         self.__dict__.update(request.__dict__)
 
@@ -72,14 +93,14 @@ class BaseInertiaResponseMixin:
     props: dict[str, Any]
     template_data: dict[str, Any]
 
-    def page_data(self) -> dict[str, Any]:
+    def page_data(self) -> PageDataDict:
         clear_history = self.request.session.pop(INERTIA_SESSION_CLEAR_HISTORY, False)
         if not isinstance(clear_history, bool):
             raise TypeError(
                 f"Expected bool for clear_history, got {type(clear_history).__name__}"
             )
 
-        _page = {
+        _page: PageDataDict = {
             "component": self.component,
             "props": self.build_props(),
             "url": self.request.get_full_path(),
@@ -98,9 +119,9 @@ def page_data(self) -> dict[str, Any]:
 
         return _page
 
-    def build_props(self) -> Any:
+    def build_props(self) -> dict[str, Any]:
         _props = {
-            **(self.request.inertia),
+            **self.request.inertia,
             **self.props,
         }
 
@@ -178,7 +199,7 @@ def build_first_load_context_and_template(
 
         return {
             "page": data,
-            **(self.template_data),
+            **self.template_data,
         }, INERTIA_TEMPLATE
 
 
@@ -261,15 +282,15 @@ def clear_history(request: HttpRequest) -> None:
 def inertia(
     component: str,
 ) -> Callable[
-    [Callable[..., HttpResponse | InertiaResponse | dict[str, Any]]],
-    Callable[..., HttpResponse],
+    [Callable[Concatenate[HttpRequest, P], R]],
+    Callable[Concatenate[HttpRequest, P], HttpResponse],
 ]:
     def decorator(
-        func: Callable[..., HttpResponse | InertiaResponse | dict[str, Any]],
-    ) -> Callable[..., HttpResponse]:
+        func: Callable[Concatenate[HttpRequest, P], R],
+    ) -> Callable[Concatenate[HttpRequest, P], HttpResponse]:
         @wraps(func)
         def process_inertia_response(
-            request: HttpRequest, *args: Any, **kwargs: Any
+            request: HttpRequest, /, *args: P.args, **kwargs: P.kwargs
         ) -> HttpResponse:
             props = func(request, *args, **kwargs)
 
diff --git a/inertia/middleware.py b/inertia/middleware.py
index 37170bf..ce3176b 100644
--- a/inertia/middleware.py
+++ b/inertia/middleware.py
@@ -1,12 +1,18 @@
-from typing import Callable
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
 
 from django.contrib import messages
-from django.http import HttpRequest, HttpResponse
 from django.middleware.csrf import get_token
 
 from .http import location
 from .settings import settings
 
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+    from django.http import HttpRequest, HttpResponse
+
 
 class InertiaMiddleware:
     def __init__(self, get_response: Callable[[HttpRequest], HttpResponse]) -> None:
diff --git a/inertia/prop_classes.py b/inertia/prop_classes.py
index 0ae8d07..b9f6058 100644
--- a/inertia/prop_classes.py
+++ b/inertia/prop_classes.py
@@ -1,13 +1,21 @@
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
-from typing import Any
+from typing import TYPE_CHECKING, Any, Generic, TypeVar, cast
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+
+T = TypeVar("T", bound=Any)
 
 
-class CallableProp:
-    def __init__(self, prop: Any) -> None:
+class CallableProp(Generic[T]):
+    def __init__(self, prop: T | Callable[[], T]) -> None:
         self.prop = prop
 
-    def __call__(self) -> Any:
-        return self.prop() if callable(self.prop) else self.prop
+    def __call__(self) -> T:
+        return cast(T, self.prop() if callable(self.prop) else self.prop)
 
 
 class MergeableProp(ABC):
@@ -20,12 +28,12 @@ class IgnoreOnFirstLoadProp:
     pass
 
 
-class OptionalProp(CallableProp, IgnoreOnFirstLoadProp):
+class OptionalProp(CallableProp[T], IgnoreOnFirstLoadProp):
     pass
 
 
-class DeferredProp(CallableProp, MergeableProp, IgnoreOnFirstLoadProp):
-    def __init__(self, prop: Any, group: str, merge: bool = False) -> None:
+class DeferredProp(CallableProp[T], MergeableProp, IgnoreOnFirstLoadProp):
+    def __init__(self, prop: T | Callable[[], T], group: str, merge: bool = False) -> None:
         super().__init__(prop)
         self.group = group
         self.merge = merge
@@ -34,6 +42,6 @@ def should_merge(self) -> bool:
         return self.merge
 
 
-class MergeProp(CallableProp, MergeableProp):
+class MergeProp(CallableProp[T], MergeableProp):
     def should_merge(self) -> bool:
         return True
diff --git a/inertia/share.py b/inertia/share.py
index ff67b9e..85c15c2 100644
--- a/inertia/share.py
+++ b/inertia/share.py
@@ -1,6 +1,12 @@
-from typing import Any
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from typing import Any
+
+    from django.http import HttpRequest
 
-from django.http import HttpRequest
 
 __all__ = ["share"]
 
diff --git a/inertia/utils.py b/inertia/utils.py
index fc79896..d64be5c 100644
--- a/inertia/utils.py
+++ b/inertia/utils.py
@@ -1,5 +1,7 @@
+from __future__ import annotations
+
 import warnings
-from typing import Any
+from typing import TYPE_CHECKING, Any, TypeVar
 
 from django.core.serializers.json import DjangoJSONEncoder
 from django.db import models
@@ -8,6 +10,12 @@
 
 from .prop_classes import DeferredProp, MergeProp, OptionalProp
 
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+
+T = TypeVar("T", bound=Any)
+
 
 def model_to_dict(model: models.Model) -> dict[str, Any]:
     return base_model_to_dict(model, exclude=("password",))
@@ -32,7 +40,7 @@ def default(self, o: Any) -> Any:
         return super().default(o)
 
 
-def lazy(prop: Any) -> OptionalProp:
+def lazy(prop: T | Callable[[], T]) -> OptionalProp[T]:
     warnings.warn(
         "lazy is deprecated and will be removed in a future version. Please use optional instead.",
         DeprecationWarning,
@@ -41,13 +49,13 @@ def lazy(prop: Any) -> OptionalProp:
     return optional(prop)
 
 
-def optional(prop: Any) -> OptionalProp:
+def optional(prop: T | Callable[[], T]) -> OptionalProp[T]:
     return OptionalProp(prop)
 
 
-def defer(prop: Any, group: str = "default", merge: bool = False) -> DeferredProp:
+def defer(prop: T | Callable[[], T], group: str = "default", merge: bool = False) -> DeferredProp[T]:
     return DeferredProp(prop, group=group, merge=merge)
 
 
-def merge(prop: Any) -> MergeProp:
+def merge(prop: T | Callable[[], T]) -> MergeProp[T]:
     return MergeProp(prop)