diff --git a/curl_cffi/requests/headers.py b/curl_cffi/requests/headers.py
index 000c03da..7c30cd19 100644
--- a/curl_cffi/requests/headers.py
+++ b/curl_cffi/requests/headers.py
@@ -102,7 +102,7 @@ def __init__(
             ]
         elif isinstance(headers, list):
             # list of "Name: Value" pairs
-            if isinstance(headers[0], (str, bytes)):
+            if isinstance(headers[0], str | bytes):
                 sep = ":" if isinstance(headers[0], str) else b":"
                 h = []
                 for line in headers:
diff --git a/curl_cffi/requests/session.py b/curl_cffi/requests/session.py
index 00157278..5c253646 100644
--- a/curl_cffi/requests/session.py
+++ b/curl_cffi/requests/session.py
@@ -7,7 +7,7 @@
 import sys
 import threading
 import warnings
-from concurrent.futures import ThreadPoolExecutor
+from concurrent.futures import ThreadPoolExecutor, Future
 from contextlib import asynccontextmanager, contextmanager, suppress
 from collections.abc import Callable
 from io import BytesIO
@@ -21,6 +21,7 @@
     Union,
     cast,
 )
+from collections.abc import AsyncGenerator, Generator
 from urllib.parse import urlparse
 from datetime import timedelta
 
@@ -245,7 +246,12 @@ def __init__(
             )
 
     def _parse_response(
-        self, curl, buffer, header_buffer, default_encoding, discard_cookies
+        self,
+        curl: Curl,
+        buffer: BytesIO,
+        header_buffer: BytesIO,
+        default_encoding: Union[str, Callable[[bytes], str]],
+        discard_cookies: bool,
     ) -> R:
         c = curl
         rsp = cast(R, self.response_class(c))
@@ -349,7 +355,7 @@ def __init__(
         thread: Optional[ThreadType] = None,
         use_thread_local_curl: bool = True,
         **kwargs: Unpack[BaseSessionParams[R]],
-    ):
+    ) -> None:
         """
         Parameters set in the ``__init__`` method will be overriden by the same
         parameter in request method.
@@ -439,7 +445,7 @@ def executor(self):
     def __enter__(self):
         return self
 
-    def __exit__(self, *args):
+    def __exit__(self, *args) -> None:
         self.close()
 
     def close(self) -> None:
@@ -453,7 +459,7 @@ def stream(
         method: HttpMethod,
         url: str,
         **kwargs: Unpack[StreamRequestParams],
-    ):
+    ) -> Generator[R, None, None]:
         """Equivalent to ``with request(..., stream=True) as r:``"""
         rsp = self.request(method=method, url=url, **kwargs, stream=True)
         try:
@@ -462,7 +468,13 @@ def stream(
             rsp.close()
 
     def ws_connect(
-        self, url, on_message=None, on_error=None, on_open=None, on_close=None, **kwargs
+        self,
+        url: str,
+        on_message=None,
+        on_error=None,
+        on_open=None,
+        on_close=None,
+        **kwargs,
     ) -> WebSocket:
         """Connects to a websocket url.
 
@@ -534,7 +546,7 @@ def request(
         max_recv_speed: int = 0,
         multipart: Optional[CurlMime] = None,
         discard_cookies: bool = False,
-    ):
+    ) -> R:
         """Send the request, see ``requests.request`` for details on parameters."""
 
         self._check_session_closed()
@@ -608,7 +620,7 @@ def perform():
                         cast(threading.Event, header_recved).set()
                     q.put(STREAM_END)  # type: ignore
 
-            def cleanup(fut):
+            def cleanup(fut: Future[None]):
                 header_parsed.wait()
                 c.reset()
 
@@ -668,31 +680,31 @@ def cleanup(fut):
             finally:
                 c.reset()
 
-    def head(self, url: str, **kwargs: Unpack[RequestParams]):
+    def head(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="HEAD", url=url, **kwargs)
 
-    def get(self, url: str, **kwargs: Unpack[RequestParams]):
+    def get(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="GET", url=url, **kwargs)
 
-    def post(self, url: str, **kwargs: Unpack[RequestParams]):
+    def post(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="POST", url=url, **kwargs)
 
-    def put(self, url: str, **kwargs: Unpack[RequestParams]):
+    def put(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="PUT", url=url, **kwargs)
 
-    def patch(self, url: str, **kwargs: Unpack[RequestParams]):
+    def patch(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="PATCH", url=url, **kwargs)
 
-    def delete(self, url: str, **kwargs: Unpack[RequestParams]):
+    def delete(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="DELETE", url=url, **kwargs)
 
-    def options(self, url: str, **kwargs: Unpack[RequestParams]):
+    def options(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="OPTIONS", url=url, **kwargs)
 
-    def trace(self, url: str, **kwargs: Unpack[RequestParams]):
+    def trace(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="TRACE", url=url, **kwargs)
 
-    def query(self, url: str, **kwargs: Unpack[RequestParams]):
+    def query(self, url: str, **kwargs: Unpack[RequestParams]) -> R:
         return self.request(method="QUERY", url=url, **kwargs)
 
 
@@ -706,7 +718,7 @@ def __init__(
         async_curl: Optional[AsyncCurl] = None,
         max_clients: int = 10,
         **kwargs: Unpack[BaseSessionParams[R]],
-    ):
+    ) -> None:
         """
         Parameters set in the ``__init__`` method will be override by the same parameter
         in request method.
@@ -766,39 +778,39 @@ def __init__(
         self.init_pool()
 
     @property
-    def loop(self):
+    def loop(self) -> asyncio.AbstractEventLoop:
         if self._loop is None:
             self._loop = asyncio.get_running_loop()
         return self._loop
 
     @property
-    def acurl(self):
+    def acurl(self) -> AsyncCurl:
         if self._acurl is None:
             self._acurl = AsyncCurl(loop=self.loop)
         return self._acurl
 
-    def init_pool(self):
-        self.pool = asyncio.LifoQueue(self.max_clients)
+    def init_pool(self) -> None:
+        self.pool: asyncio.LifoQueue[Curl | None] = asyncio.LifoQueue(self.max_clients)
         while True:
             try:
                 self.pool.put_nowait(None)
             except asyncio.QueueFull:
                 break
 
-    async def pop_curl(self):
+    async def pop_curl(self) -> Curl:
         curl = await self.pool.get()
         if curl is None:
             curl = Curl(debug=self.debug)
         return curl
 
-    def push_curl(self, curl):
+    def push_curl(self, curl: Curl | None) -> None:
         with suppress(asyncio.QueueFull):
             self.pool.put_nowait(curl)
 
-    async def __aenter__(self):
+    async def __aenter__(self):  # TODO: -> Self
         return self
 
-    async def __aexit__(self, *args):
+    async def __aexit__(self, *args) -> None:
         await self.close()
         return None
 
@@ -814,7 +826,7 @@ async def close(self) -> None:
             except asyncio.QueueEmpty:
                 break
 
-    def release_curl(self, curl):
+    def release_curl(self, curl: Curl) -> None:
         curl.clean_handles_and_buffers()
         if not self._closed:
             self.acurl.remove_handle(curl)
@@ -829,7 +841,7 @@ async def stream(
         method: HttpMethod,
         url: str,
         **kwargs: Unpack[StreamRequestParams],
-    ):
+    ) -> AsyncGenerator[R, None, None]:
         """Equivalent to ``async with request(..., stream=True) as r:``"""
         rsp = await self.request(method=method, url=url, **kwargs, stream=True)
         try:
@@ -1095,7 +1107,7 @@ async def request(
         if stream:
             task = self.acurl.add_handle(curl)
 
-            async def perform():
+            async def perform() -> None:
                 try:
                     await task
                 except CurlError as e:
diff --git a/curl_cffi/requests/utils.py b/curl_cffi/requests/utils.py
index 5055bbdc..55e2a67e 100644
--- a/curl_cffi/requests/utils.py
+++ b/curl_cffi/requests/utils.py
@@ -118,7 +118,7 @@ def update_url_params(url: str, params: Union[dict, list, tuple]) -> str:
     new_args_counter = Counter(x[0] for x in params)
     for key, value in params:
         # Bool and Dict values should be converted to json-friendly values
-        if isinstance(value, (bool, dict)):
+        if isinstance(value, bool | dict):
             value = dumps(value)
         # 1 to 1 mapping, we have to search and update it.
         if old_args_counter.get(key) == 1 and new_args_counter.get(key) == 1:
@@ -395,7 +395,7 @@ def set_curl_options(
     c.setopt(CurlOpt.URL, url.encode())
 
     # data/body/json
-    if isinstance(data, (dict, list, tuple)):
+    if isinstance(data, dict | list | tuple):
         body = urlencode(data).encode()
     elif isinstance(data, str):
         body = data.encode()
@@ -455,7 +455,7 @@ def set_curl_options(
         update_header_line(
             header_lines, "Content-Type", "application/x-www-form-urlencoded"
         )
-    if isinstance(data, (str, bytes)) and data:
+    if isinstance(data, str | bytes) and data:
         update_header_line(header_lines, "Content-Type", "application/octet-stream")
 
     # Never send `Expect` header.
@@ -514,7 +514,7 @@ def set_curl_options(
             c.setopt(CurlOpt.LOW_SPEED_LIMIT, 1)
             c.setopt(CurlOpt.LOW_SPEED_TIME, math.ceil(all_timeout))
 
-    elif isinstance(timeout, (int, float)):
+    elif isinstance(timeout, int | float):
         if not stream:
             c.setopt(CurlOpt.TIMEOUT_MS, int(timeout * 1000))
         else:
diff --git a/curl_cffi/requests/websockets.py b/curl_cffi/requests/websockets.py
index 9560a1bd..480b9a9b 100644
--- a/curl_cffi/requests/websockets.py
+++ b/curl_cffi/requests/websockets.py
@@ -906,7 +906,7 @@ async def send(
         # cURL expects bytes
         if isinstance(payload, str):
             payload = payload.encode("utf-8")
-        elif isinstance(payload, (bytearray, memoryview)):
+        elif isinstance(payload, bytearray | memoryview):
             payload = bytes(payload)
 
         try: