diff --git a/findmy/accessory.py b/findmy/accessory.py
index 16f699d..f859568 100644
--- a/findmy/accessory.py
+++ b/findmy/accessory.py
@@ -18,6 +18,7 @@
 from .util import crypto
 
 if TYPE_CHECKING:
+    import io
     from collections.abc import Generator
     from pathlib import Path
 
@@ -269,7 +270,7 @@ def keys_at(self, ind: int) -> set[KeyPair]:
     @classmethod
     def from_plist(
         cls,
-        plist: str | Path | dict | bytes,
+        plist: str | Path | dict | bytes | io.BufferedIOBase,
         key_alignment_plist: str | Path | dict | bytes | None = None,
         *,
         name: str | None = None,
@@ -322,7 +323,7 @@ def from_plist(
         )
 
     @override
-    def to_json(self, path: str | Path | None = None, /) -> FindMyAccessoryMapping:
+    def to_json(self, path: str | Path | io.TextIOBase | None = None, /) -> FindMyAccessoryMapping:
         alignment_date = None
         if self._alignment_date is not None:
             alignment_date = self._alignment_date.isoformat()
@@ -346,7 +347,7 @@ def to_json(self, path: str | Path | None = None, /) -> FindMyAccessoryMapping:
     @override
     def from_json(
         cls,
-        val: str | Path | FindMyAccessoryMapping,
+        val: str | Path | io.TextIOBase | io.BufferedIOBase | FindMyAccessoryMapping,
         /,
     ) -> FindMyAccessory:
         val = util.files.read_data_json(val)
diff --git a/findmy/keys.py b/findmy/keys.py
index af584da..d5418e2 100644
--- a/findmy/keys.py
+++ b/findmy/keys.py
@@ -18,6 +18,7 @@
 from .util import crypto, parsers
 
 if TYPE_CHECKING:
+    import io
     from collections.abc import Generator
     from pathlib import Path
 
@@ -197,7 +198,7 @@ def adv_key_bytes(self) -> bytes:
         return int.to_bytes(key_bytes, 28, "big")
 
     @override
-    def to_json(self, dst: str | Path | None = None, /) -> KeyPairMapping:
+    def to_json(self, dst: str | Path | io.TextIOBase | None = None, /) -> KeyPairMapping:
         return save_and_return_json(
             {
                 "type": "keypair",
@@ -210,7 +211,9 @@ def to_json(self, dst: str | Path | None = None, /) -> KeyPairMapping:
 
     @classmethod
     @override
-    def from_json(cls, val: str | Path | KeyPairMapping, /) -> KeyPair:
+    def from_json(
+        cls, val: str | Path | io.TextIOBase | io.BufferedIOBase | KeyPairMapping, /
+    ) -> KeyPair:
         val = read_data_json(val)
         assert val["type"] == "keypair"
 
diff --git a/findmy/reports/account.py b/findmy/reports/account.py
index 7cbd571..ce731e7 100644
--- a/findmy/reports/account.py
+++ b/findmy/reports/account.py
@@ -48,6 +48,7 @@
 )
 
 if TYPE_CHECKING:
+    import io
     from collections.abc import Sequence
     from pathlib import Path
 
@@ -433,7 +434,7 @@ def last_name(self) -> str | None:
         return self._account_info["last_name"] if self._account_info else None
 
     @override
-    def to_json(self, path: str | Path | None = None, /) -> AccountStateMapping:
+    def to_json(self, path: str | Path | io.TextIOBase | None = None, /) -> AccountStateMapping:
         res: AccountStateMapping = {
             "type": "account",
             "ids": {"uid": self._uid, "devid": self._devid},
@@ -455,7 +456,7 @@ def to_json(self, path: str | Path | None = None, /) -> AccountStateMapping:
     @override
     def from_json(
         cls,
-        val: str | Path | AccountStateMapping,
+        val: str | Path | io.TextIOBase | io.BufferedIOBase | AccountStateMapping,
         /,
         *,
         anisette_libs_path: str | Path | None = None,
@@ -1048,7 +1049,7 @@ def to_json(self, dst: str | Path | None = None, /) -> AccountStateMapping:
     @override
     def from_json(
         cls,
-        val: str | Path | AccountStateMapping,
+        val: str | Path | io.TextIOBase | io.BufferedIOBase | AccountStateMapping,
         /,
         *,
         anisette_libs_path: str | Path | None = None,
diff --git a/findmy/reports/anisette.py b/findmy/reports/anisette.py
index e7c7341..2f22dc6 100644
--- a/findmy/reports/anisette.py
+++ b/findmy/reports/anisette.py
@@ -4,6 +4,7 @@
 
 import asyncio
 import base64
+import io
 import locale
 import logging
 import time
@@ -205,7 +206,7 @@ def __init__(self, server_url: str) -> None:
         self._closed = False
 
     @override
-    def to_json(self, dst: str | Path | None = None, /) -> RemoteAnisetteMapping:
+    def to_json(self, dst: str | Path | io.TextIOBase | None = None, /) -> RemoteAnisetteMapping:
         """See :meth:`BaseAnisetteProvider.serialize`."""
         return util.files.save_and_return_json(
             {
@@ -217,7 +218,9 @@ def to_json(self, dst: str | Path | None = None, /) -> RemoteAnisetteMapping:
 
     @classmethod
     @override
-    def from_json(cls, val: str | Path | RemoteAnisetteMapping) -> RemoteAnisetteProvider:
+    def from_json(
+        cls, val: str | Path | io.TextIOBase | io.BufferedIOBase | RemoteAnisetteMapping
+    ) -> RemoteAnisetteProvider:
         """See :meth:`BaseAnisetteProvider.deserialize`."""
         val = util.files.read_data_json(val)
 
@@ -349,7 +352,7 @@ async def _get_ani(self) -> Anisette:
         return ani
 
     @override
-    def to_json(self, dst: str | Path | None = None, /) -> LocalAnisetteMapping:
+    def to_json(self, dst: str | Path | io.TextIOBase | None = None, /) -> LocalAnisetteMapping:
         """See :meth:`BaseAnisetteProvider.serialize`."""
         if self._ani is None:
             # Anisette has not been called yet, so the future has not yet resolved.
@@ -378,7 +381,7 @@ def to_json(self, dst: str | Path | None = None, /) -> LocalAnisetteMapping:
     @override
     def from_json(
         cls,
-        val: str | Path | LocalAnisetteMapping,
+        val: str | Path | io.TextIOBase | io.BufferedIOBase | LocalAnisetteMapping,
         *,
         libs_path: str | Path | None = None,
     ) -> LocalAnisetteProvider:
diff --git a/findmy/reports/reports.py b/findmy/reports/reports.py
index cec9eb1..3c9c162 100644
--- a/findmy/reports/reports.py
+++ b/findmy/reports/reports.py
@@ -21,6 +21,7 @@
 from findmy.keys import HasHashedPublicKey, KeyPair, KeyPairMapping, KeyPairType
 
 if TYPE_CHECKING:
+    import io
     from collections.abc import Sequence
     from pathlib import Path
 
@@ -199,7 +200,7 @@ def status(self) -> int:
     @overload
     def to_json(
         self,
-        dst: str | Path | None = None,
+        dst: str | Path | io.TextIOBase | None = None,
         /,
         *,
         include_key: Literal[True],
@@ -209,7 +210,7 @@ def to_json(
     @overload
     def to_json(
         self,
-        dst: str | Path | None = None,
+        dst: str | Path | io.TextIOBase | None = None,
         /,
         *,
         include_key: Literal[False],
@@ -219,7 +220,7 @@ def to_json(
     @overload
     def to_json(
         self,
-        dst: str | Path | None = None,
+        dst: str | Path | io.TextIOBase | None = None,
         /,
         *,
         include_key: None = None,
@@ -229,7 +230,7 @@ def to_json(
     @override
     def to_json(
         self,
-        dst: str | Path | None = None,
+        dst: str | Path | io.TextIOBase | None = None,
         /,
         *,
         include_key: bool | None = None,
@@ -258,7 +259,9 @@ def to_json(
 
     @classmethod
     @override
-    def from_json(cls, val: str | Path | LocationReportMapping, /) -> LocationReport:
+    def from_json(
+        cls, val: str | Path | io.TextIOBase | io.BufferedIOBase | LocationReportMapping, /
+    ) -> LocationReport:
         val = util.files.read_data_json(val)
         assert val["type"] == "locReportEncrypted" or val["type"] == "locReportDecrypted"
 
diff --git a/findmy/util/files.py b/findmy/util/files.py
index a366f5a..b34170f 100644
--- a/findmy/util/files.py
+++ b/findmy/util/files.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import io
 import json
 import plistlib
 from collections.abc import Mapping
@@ -11,7 +12,7 @@
 _T = TypeVar("_T", bound=Mapping)
 
 
-def save_and_return_json(data: _T, dst: str | Path | None) -> _T:
+def save_and_return_json(data: _T, dst: str | Path | io.TextIOBase | None) -> _T:
     """Save and return a JSON-serializable data structure."""
     if dst is None:
         return data
@@ -19,12 +20,15 @@ def save_and_return_json(data: _T, dst: str | Path | None) -> _T:
     if isinstance(dst, str):
         dst = Path(dst)
 
-    dst.write_text(json.dumps(data, indent=4))
+    if isinstance(dst, io.IOBase):
+        json.dump(data, dst, indent=4)
+    elif isinstance(dst, Path):
+        dst.write_text(json.dumps(data, indent=4))
 
     return data
 
 
-def read_data_json(val: str | Path | _T) -> _T:
+def read_data_json(val: str | Path | io.TextIOBase | io.BufferedIOBase | _T) -> _T:
     """Read JSON data from a file if a path is passed, or return the argument itself."""
     if isinstance(val, str):
         val = Path(val)
@@ -32,10 +36,13 @@ def read_data_json(val: str | Path | _T) -> _T:
     if isinstance(val, Path):
         val = cast("_T", json.loads(val.read_text()))
 
+    if isinstance(val, io.IOBase):
+        val = cast("_T", json.load(val))
+
     return val
 
 
-def save_and_return_plist(data: _T, dst: str | Path | None) -> _T:
+def save_and_return_plist(data: _T, dst: str | Path | io.BufferedIOBase | None) -> _T:
     """Save and return a Plist file."""
     if dst is None:
         return data
@@ -43,12 +50,15 @@ def save_and_return_plist(data: _T, dst: str | Path | None) -> _T:
     if isinstance(dst, str):
         dst = Path(dst)
 
-    dst.write_bytes(plistlib.dumps(data))
+    if isinstance(dst, io.IOBase):
+        dst.write(plistlib.dumps(data))
+    elif isinstance(dst, Path):
+        dst.write_bytes(plistlib.dumps(data))
 
     return data
 
 
-def read_data_plist(val: str | Path | _T | bytes) -> _T:
+def read_data_plist(val: str | Path | io.BufferedIOBase | _T | bytes) -> _T:
     """Read Plist data from a file if a path is passed, or return the argument itself."""
     if isinstance(val, str):
         val = Path(val)
@@ -59,4 +69,7 @@ def read_data_plist(val: str | Path | _T | bytes) -> _T:
     if isinstance(val, bytes):
         val = cast("_T", plistlib.loads(val))
 
+    if isinstance(val, io.IOBase):
+        val = cast("_T", plistlib.loads(val.read()))
+
     return val