diff --git a/stdlib/xmlrpc/client.pyi b/stdlib/xmlrpc/client.pyi
index 150291009..0e048f578 100644
--- a/stdlib/xmlrpc/client.pyi
+++ b/stdlib/xmlrpc/client.pyi
@@ -2,7 +2,7 @@ import gzip
 import http.client
 import sys
 import time
-from _typeshed import Self, SupportsRead, SupportsWrite
+from _typeshed import ReadableBuffer, Self, SupportsRead, SupportsWrite, _BufferWithLen
 from collections.abc import Callable, Iterable, Mapping
 from datetime import datetime
 from io import BytesIO
@@ -15,7 +15,20 @@ class _SupportsTimeTuple(Protocol):
 
 _DateTimeComparable: TypeAlias = DateTime | datetime | str | _SupportsTimeTuple
 _Marshallable: TypeAlias = (
-    bool | int | float | str | bytes | None | tuple[Any, ...] | list[Any] | dict[Any, Any] | datetime | DateTime | Binary
+    bool
+    | int
+    | float
+    | str
+    | bytes
+    | bytearray
+    | None
+    | tuple[_Marshallable, ...]
+    # Ideally we'd use _Marshallable for list and dict, but invariance makes that impractical
+    | list[Any]
+    | dict[str, Any]
+    | datetime
+    | DateTime
+    | Binary
 )
 _XMLDate: TypeAlias = int | datetime | tuple[int, ...] | time.struct_time
 _HostType: TypeAlias = Union[tuple[str, dict[str, str]], str]
@@ -83,18 +96,18 @@ def _datetime_type(data: str) -> datetime: ...  # undocumented
 class Binary:
 
     data: bytes
-    def __init__(self, data: bytes | None = ...) -> None: ...
-    def decode(self, data: bytes) -> None: ...
+    def __init__(self, data: bytes | bytearray | None = ...) -> None: ...
+    def decode(self, data: ReadableBuffer) -> None: ...
     def encode(self, out: SupportsWrite[str]) -> None: ...
     def __eq__(self, other: object) -> bool: ...
 
-def _binary(data: bytes) -> Binary: ...  # undocumented
+def _binary(data: ReadableBuffer) -> Binary: ...  # undocumented
 
 WRAPPERS: tuple[type[DateTime], type[Binary]]  # undocumented
 
 class ExpatParser:  # undocumented
     def __init__(self, target: Unmarshaller) -> None: ...
-    def feed(self, data: str | bytes) -> None: ...
+    def feed(self, data: str | ReadableBuffer) -> None: ...
     def close(self) -> None: ...
 
 _WriteCallback: TypeAlias = Callable[[str], object]
@@ -115,7 +128,7 @@ class Marshaller:
     def dump_int(self, value: int, write: _WriteCallback) -> None: ...
     def dump_double(self, value: float, write: _WriteCallback) -> None: ...
     def dump_unicode(self, value: str, write: _WriteCallback, escape: Callable[[str], str] = ...) -> None: ...
-    def dump_bytes(self, value: bytes, write: _WriteCallback) -> None: ...
+    def dump_bytes(self, value: ReadableBuffer, write: _WriteCallback) -> None: ...
     def dump_array(self, value: Iterable[_Marshallable], write: _WriteCallback) -> None: ...
     def dump_struct(
         self, value: Mapping[str, _Marshallable], write: _WriteCallback, escape: Callable[[str], str] = ...
@@ -196,13 +209,13 @@ def dumps(
     allow_none: bool = ...,
 ) -> str: ...
 def loads(data: str, use_datetime: bool = ..., use_builtin_types: bool = ...) -> tuple[tuple[_Marshallable, ...], str | None]: ...
-def gzip_encode(data: bytes) -> bytes: ...  # undocumented
-def gzip_decode(data: bytes, max_decode: int = ...) -> bytes: ...  # undocumented
+def gzip_encode(data: ReadableBuffer) -> bytes: ...  # undocumented
+def gzip_decode(data: ReadableBuffer, max_decode: int = ...) -> bytes: ...  # undocumented
 
 class GzipDecodedResponse(gzip.GzipFile):  # undocumented
 
     io: BytesIO
-    def __init__(self, response: SupportsRead[bytes]) -> None: ...
+    def __init__(self, response: SupportsRead[ReadableBuffer]) -> None: ...
 
 class _Method:  # undocumented
 
@@ -231,17 +244,21 @@ class Transport:
     else:
         def __init__(self, use_datetime: bool = ..., use_builtin_types: bool = ...) -> None: ...
 
-    def request(self, host: _HostType, handler: str, request_body: bytes, verbose: bool = ...) -> tuple[_Marshallable, ...]: ...
+    def request(
+        self, host: _HostType, handler: str, request_body: _BufferWithLen, verbose: bool = ...
+    ) -> tuple[_Marshallable, ...]: ...
     def single_request(
-        self, host: _HostType, handler: str, request_body: bytes, verbose: bool = ...
+        self, host: _HostType, handler: str, request_body: _BufferWithLen, verbose: bool = ...
     ) -> tuple[_Marshallable, ...]: ...
     def getparser(self) -> tuple[ExpatParser, Unmarshaller]: ...
     def get_host_info(self, host: _HostType) -> tuple[str, list[tuple[str, str]], dict[str, str]]: ...
     def make_connection(self, host: _HostType) -> http.client.HTTPConnection: ...
     def close(self) -> None: ...
-    def send_request(self, host: _HostType, handler: str, request_body: bytes, debug: bool) -> http.client.HTTPConnection: ...
+    def send_request(
+        self, host: _HostType, handler: str, request_body: _BufferWithLen, debug: bool
+    ) -> http.client.HTTPConnection: ...
     def send_headers(self, connection: http.client.HTTPConnection, headers: list[tuple[str, str]]) -> None: ...
-    def send_content(self, connection: http.client.HTTPConnection, request_body: bytes) -> None: ...
+    def send_content(self, connection: http.client.HTTPConnection, request_body: _BufferWithLen) -> None: ...
     def parse_response(self, response: http.client.HTTPResponse) -> tuple[_Marshallable, ...]: ...
 
 class SafeTransport(Transport):
diff --git a/stdlib/xmlrpc/server.pyi b/stdlib/xmlrpc/server.pyi
index c11d8d8e7..4d28974cb 100644
--- a/stdlib/xmlrpc/server.pyi
+++ b/stdlib/xmlrpc/server.pyi
@@ -2,14 +2,10 @@ import http.server
 import pydoc
 import socketserver
 from collections.abc import Callable, Iterable, Mapping
-from datetime import datetime
 from re import Pattern
 from typing import Any, ClassVar, Protocol
 from typing_extensions import TypeAlias
-from xmlrpc.client import Fault
-
-# TODO: Recursive type on tuple, list, dict
-_Marshallable: TypeAlias = None | bool | int | float | str | bytes | tuple[Any, ...] | list[Any] | dict[Any, Any] | datetime
+from xmlrpc.client import Fault, _Marshallable
 
 # The dispatch accepts anywhere from 0 to N arguments, no easy way to allow this in mypy
 class _DispatchArity0(Protocol):