diff --git a/homeassistant/components/api/__init__.py b/homeassistant/components/api/__init__.py
index 5e965cd370c..d380e0ce3ee 100644
--- a/homeassistant/components/api/__init__.py
+++ b/homeassistant/components/api/__init__.py
@@ -214,7 +214,7 @@ class APIStatesView(HomeAssistantView):
                 if entity_perm(state.entity_id, "read")
             )
         response = web.Response(
-            body=f'[{",".join(states)}]',
+            body=b"[" + b",".join(states) + b"]",
             content_type=CONTENT_TYPE_JSON,
             zlib_executor_size=32768,
         )
diff --git a/homeassistant/components/config/device_registry.py b/homeassistant/components/config/device_registry.py
index 74c15da2f00..cbf3623e7a8 100644
--- a/homeassistant/components/config/device_registry.py
+++ b/homeassistant/components/config/device_registry.py
@@ -45,16 +45,16 @@ def websocket_list_devices(
     msg_json_prefix = (
         f'{{"id":{msg["id"]},"type": "{websocket_api.const.TYPE_RESULT}",'
         f'"success":true,"result": ['
-    )
+    ).encode()
     # Concatenate cached entity registry item JSON serializations
     msg_json = (
         msg_json_prefix
-        + ",".join(
+        + b",".join(
             entry.json_repr
             for entry in registry.devices.values()
             if entry.json_repr is not None
         )
-        + "]}"
+        + b"]}"
     )
     connection.send_message(msg_json)
 
diff --git a/homeassistant/components/config/entity_registry.py b/homeassistant/components/config/entity_registry.py
index a0e0d1877fa..f1c1fadc144 100644
--- a/homeassistant/components/config/entity_registry.py
+++ b/homeassistant/components/config/entity_registry.py
@@ -43,20 +43,23 @@ def websocket_list_entities(
     msg_json_prefix = (
         f'{{"id":{msg["id"]},"type": "{websocket_api.const.TYPE_RESULT}",'
         '"success":true,"result": ['
-    )
+    ).encode()
     # Concatenate cached entity registry item JSON serializations
     msg_json = (
         msg_json_prefix
-        + ",".join(
+        + b",".join(
             entry.partial_json_repr
             for entry in registry.entities.values()
             if entry.partial_json_repr is not None
         )
-        + "]}"
+        + b"]}"
     )
     connection.send_message(msg_json)
 
 
+_ENTITY_CATEGORIES_JSON = json_dumps(er.ENTITY_CATEGORY_INDEX_TO_VALUE)
+
+
 @websocket_api.websocket_command(
     {vol.Required("type"): "config/entity_registry/list_for_display"}
 )
@@ -69,20 +72,19 @@ def websocket_list_entities_for_display(
     """Handle list registry entries command."""
     registry = er.async_get(hass)
     # Build start of response message
-    entity_categories = json_dumps(er.ENTITY_CATEGORY_INDEX_TO_VALUE)
     msg_json_prefix = (
         f'{{"id":{msg["id"]},"type":"{websocket_api.const.TYPE_RESULT}","success":true,'
-        f'"result":{{"entity_categories":{entity_categories},"entities":['
-    )
+        f'"result":{{"entity_categories":{_ENTITY_CATEGORIES_JSON},"entities":['
+    ).encode()
     # Concatenate cached entity registry item JSON serializations
     msg_json = (
         msg_json_prefix
-        + ",".join(
+        + b",".join(
             entry.display_json_repr
             for entry in registry.entities.values()
             if entry.disabled_by is None and entry.display_json_repr is not None
         )
-        + "]}}"
+        + b"]}}"
     )
     connection.send_message(msg_json)
 
diff --git a/homeassistant/components/history/websocket_api.py b/homeassistant/components/history/websocket_api.py
index 5bc14cd4c02..25422004797 100644
--- a/homeassistant/components/history/websocket_api.py
+++ b/homeassistant/components/history/websocket_api.py
@@ -34,7 +34,7 @@ from homeassistant.helpers.event import (
     async_track_point_in_utc_time,
     async_track_state_change_event,
 )
-from homeassistant.helpers.json import JSON_DUMP
+from homeassistant.helpers.json import json_bytes
 from homeassistant.helpers.typing import EventType
 import homeassistant.util.dt as dt_util
 
@@ -72,9 +72,9 @@ def _ws_get_significant_states(
     significant_changes_only: bool,
     minimal_response: bool,
     no_attributes: bool,
-) -> str:
+) -> bytes:
     """Fetch history significant_states and convert them to json in the executor."""
-    return JSON_DUMP(
+    return json_bytes(
         messages.result_message(
             msg_id,
             history.get_significant_states(
@@ -201,9 +201,9 @@ def _generate_websocket_response(
     start_time: dt,
     end_time: dt,
     states: MutableMapping[str, list[dict[str, Any]]],
-) -> str:
+) -> bytes:
     """Generate a websocket response."""
-    return JSON_DUMP(
+    return json_bytes(
         messages.event_message(
             msg_id, _generate_stream_message(states, start_time, end_time)
         )
@@ -221,7 +221,7 @@ def _generate_historical_response(
     minimal_response: bool,
     no_attributes: bool,
     send_empty: bool,
-) -> tuple[float, dt | None, str | None]:
+) -> tuple[float, dt | None, bytes | None]:
     """Generate a historical response."""
     states = cast(
         MutableMapping[str, list[dict[str, Any]]],
@@ -346,7 +346,7 @@ async def _async_events_consumer(
 
         if history_states := _events_to_compressed_states(events, no_attributes):
             connection.send_message(
-                JSON_DUMP(
+                json_bytes(
                     messages.event_message(
                         msg_id,
                         {"states": history_states},
diff --git a/homeassistant/components/logbook/websocket_api.py b/homeassistant/components/logbook/websocket_api.py
index 4afa40cb14f..82124247adf 100644
--- a/homeassistant/components/logbook/websocket_api.py
+++ b/homeassistant/components/logbook/websocket_api.py
@@ -16,7 +16,7 @@ from homeassistant.components.websocket_api import messages
 from homeassistant.components.websocket_api.connection import ActiveConnection
 from homeassistant.core import CALLBACK_TYPE, Event, HomeAssistant, callback
 from homeassistant.helpers.event import async_track_point_in_utc_time
-from homeassistant.helpers.json import JSON_DUMP
+from homeassistant.helpers.json import json_bytes
 import homeassistant.util.dt as dt_util
 
 from .const import DOMAIN
@@ -70,7 +70,7 @@ def _async_send_empty_response(
     stream_end_time = end_time or dt_util.utcnow()
     empty_stream_message = _generate_stream_message([], start_time, stream_end_time)
     empty_response = messages.event_message(msg_id, empty_stream_message)
-    connection.send_message(JSON_DUMP(empty_response))
+    connection.send_message(json_bytes(empty_response))
 
 
 async def _async_send_historical_events(
@@ -165,7 +165,7 @@ async def _async_get_ws_stream_events(
     formatter: Callable[[int, Any], dict[str, Any]],
     event_processor: EventProcessor,
     partial: bool,
-) -> tuple[str, dt | None]:
+) -> tuple[bytes, dt | None]:
     """Async wrapper around _ws_formatted_get_events."""
     return await get_instance(hass).async_add_executor_job(
         _ws_stream_get_events,
@@ -196,7 +196,7 @@ def _ws_stream_get_events(
     formatter: Callable[[int, Any], dict[str, Any]],
     event_processor: EventProcessor,
     partial: bool,
-) -> tuple[str, dt | None]:
+) -> tuple[bytes, dt | None]:
     """Fetch events and convert them to json in the executor."""
     events = event_processor.get_events(start_day, end_day)
     last_time = None
@@ -209,7 +209,7 @@ def _ws_stream_get_events(
         # data in case the UI needs to show that historical
         # data is still loading in the future
         message["partial"] = True
-    return JSON_DUMP(formatter(msg_id, message)), last_time
+    return json_bytes(formatter(msg_id, message)), last_time
 
 
 async def _async_events_consumer(
@@ -238,7 +238,7 @@ async def _async_events_consumer(
             async_event_to_row(e) for e in events
         ):
             connection.send_message(
-                JSON_DUMP(
+                json_bytes(
                     messages.event_message(
                         msg_id,
                         {"events": logbook_events},
@@ -435,9 +435,9 @@ def _ws_formatted_get_events(
     start_time: dt,
     end_time: dt,
     event_processor: EventProcessor,
-) -> str:
+) -> bytes:
     """Fetch events and convert them to json in the executor."""
-    return JSON_DUMP(
+    return json_bytes(
         messages.result_message(
             msg_id, event_processor.get_events(start_time, end_time)
         )
diff --git a/homeassistant/components/recorder/websocket_api.py b/homeassistant/components/recorder/websocket_api.py
index 733dafeba27..30c3bb31a47 100644
--- a/homeassistant/components/recorder/websocket_api.py
+++ b/homeassistant/components/recorder/websocket_api.py
@@ -12,7 +12,7 @@ from homeassistant.components.websocket_api import messages
 from homeassistant.core import HomeAssistant, callback, valid_entity_id
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import config_validation as cv
-from homeassistant.helpers.json import JSON_DUMP
+from homeassistant.helpers.json import json_bytes
 from homeassistant.util import dt as dt_util
 from homeassistant.util.unit_conversion import (
     DataRateConverter,
@@ -97,9 +97,9 @@ def _ws_get_statistic_during_period(
     statistic_id: str,
     types: set[Literal["max", "mean", "min", "change"]] | None,
     units: dict[str, str],
-) -> str:
+) -> bytes:
     """Fetch statistics and convert them to json in the executor."""
-    return JSON_DUMP(
+    return json_bytes(
         messages.result_message(
             msg_id,
             statistic_during_period(
@@ -155,7 +155,7 @@ def _ws_get_statistics_during_period(
     period: Literal["5minute", "day", "hour", "week", "month"],
     units: dict[str, str],
     types: set[Literal["change", "last_reset", "max", "mean", "min", "state", "sum"]],
-) -> str:
+) -> bytes:
     """Fetch statistics and convert them to json in the executor."""
     result = statistics_during_period(
         hass,
@@ -174,7 +174,7 @@ def _ws_get_statistics_during_period(
                 item["end"] = int(end * 1000)
             if (last_reset := item.get("last_reset")) is not None:
                 item["last_reset"] = int(last_reset * 1000)
-    return JSON_DUMP(messages.result_message(msg_id, result))
+    return json_bytes(messages.result_message(msg_id, result))
 
 
 async def ws_handle_get_statistics_during_period(
@@ -242,12 +242,12 @@ def _ws_get_list_statistic_ids(
     hass: HomeAssistant,
     msg_id: int,
     statistic_type: Literal["mean"] | Literal["sum"] | None = None,
-) -> str:
+) -> bytes:
     """Fetch a list of available statistic_id and convert them to JSON.
 
     Runs in the executor.
     """
-    return JSON_DUMP(
+    return json_bytes(
         messages.result_message(msg_id, list_statistic_ids(hass, None, statistic_type))
     )
 
diff --git a/homeassistant/components/websocket_api/auth.py b/homeassistant/components/websocket_api/auth.py
index 2c86a26efc9..f09c2601328 100644
--- a/homeassistant/components/websocket_api/auth.py
+++ b/homeassistant/components/websocket_api/auth.py
@@ -57,7 +57,7 @@ class AuthPhase:
         self,
         logger: WebSocketAdapter,
         hass: HomeAssistant,
-        send_message: Callable[[str | dict[str, Any]], None],
+        send_message: Callable[[bytes | str | dict[str, Any]], None],
         cancel_ws: CALLBACK_TYPE,
         request: Request,
     ) -> None:
diff --git a/homeassistant/components/websocket_api/commands.py b/homeassistant/components/websocket_api/commands.py
index 0edb6ad5261..32f59bd0c5f 100644
--- a/homeassistant/components/websocket_api/commands.py
+++ b/homeassistant/components/websocket_api/commands.py
@@ -104,7 +104,7 @@ def pong_message(iden: int) -> dict[str, Any]:
 
 @callback
 def _forward_events_check_permissions(
-    send_message: Callable[[str | dict[str, Any] | Callable[[], str]], None],
+    send_message: Callable[[bytes | str | dict[str, Any] | Callable[[], str]], None],
     user: User,
     msg_id: int,
     event: Event,
@@ -124,7 +124,7 @@ def _forward_events_check_permissions(
 
 @callback
 def _forward_events_unconditional(
-    send_message: Callable[[str | dict[str, Any] | Callable[[], str]], None],
+    send_message: Callable[[bytes | str | dict[str, Any] | Callable[[], str]], None],
     msg_id: int,
     event: Event,
 ) -> None:
@@ -352,17 +352,17 @@ def handle_get_states(
 
 
 def _send_handle_get_states_response(
-    connection: ActiveConnection, msg_id: int, serialized_states: list[str]
+    connection: ActiveConnection, msg_id: int, serialized_states: list[bytes]
 ) -> None:
     """Send handle get states response."""
     connection.send_message(
-        construct_result_message(msg_id, f'[{",".join(serialized_states)}]')
+        construct_result_message(msg_id, b"[" + b",".join(serialized_states) + b"]")
     )
 
 
 @callback
 def _forward_entity_changes(
-    send_message: Callable[[str | dict[str, Any] | Callable[[], str]], None],
+    send_message: Callable[[str | bytes | dict[str, Any] | Callable[[], str]], None],
     entity_ids: set[str],
     user: User,
     msg_id: int,
@@ -444,11 +444,19 @@ def handle_subscribe_entities(
 
 
 def _send_handle_entities_init_response(
-    connection: ActiveConnection, msg_id: int, serialized_states: list[str]
+    connection: ActiveConnection, msg_id: int, serialized_states: list[bytes]
 ) -> None:
     """Send handle entities init response."""
     connection.send_message(
-        f'{{"id":{msg_id},"type":"event","event":{{"a":{{{",".join(serialized_states)}}}}}}}'
+        b"".join(
+            (
+                b'{"id":',
+                str(msg_id).encode(),
+                b',"type":"event","event":{"a":{',
+                b",".join(serialized_states),
+                b"}}}",
+            )
+        )
     )
 
 
@@ -474,7 +482,7 @@ async def handle_get_services(
 ) -> None:
     """Handle get services command."""
     payload = await _async_get_all_descriptions_json(hass)
-    connection.send_message(construct_result_message(msg["id"], payload))
+    connection.send_message(construct_result_message(msg["id"], payload.encode()))
 
 
 @callback
diff --git a/homeassistant/components/websocket_api/connection.py b/homeassistant/components/websocket_api/connection.py
index 25b6c90d1ba..e4540dfac35 100644
--- a/homeassistant/components/websocket_api/connection.py
+++ b/homeassistant/components/websocket_api/connection.py
@@ -51,7 +51,7 @@ class ActiveConnection:
         self,
         logger: WebSocketAdapter,
         hass: HomeAssistant,
-        send_message: Callable[[str | dict[str, Any]], None],
+        send_message: Callable[[bytes | str | dict[str, Any]], None],
         user: User,
         refresh_token: RefreshToken,
     ) -> None:
@@ -244,7 +244,7 @@ class ActiveConnection:
 
     @callback
     def _connect_closed_error(
-        self, msg: str | dict[str, Any] | Callable[[], str]
+        self, msg: bytes | str | dict[str, Any] | Callable[[], str]
     ) -> None:
         """Send a message when the connection is closed."""
         self.logger.debug("Tried to send message %s on closed connection", msg)
diff --git a/homeassistant/components/websocket_api/http.py b/homeassistant/components/websocket_api/http.py
index f2f667368c3..c8c5d00cb2a 100644
--- a/homeassistant/components/websocket_api/http.py
+++ b/homeassistant/components/websocket_api/http.py
@@ -5,6 +5,7 @@ import asyncio
 from collections import deque
 from collections.abc import Callable
 import datetime as dt
+from functools import partial
 import logging
 from typing import TYPE_CHECKING, Any, Final
 
@@ -28,7 +29,7 @@ from .const import (
     URL,
 )
 from .error import Disconnect
-from .messages import message_to_json
+from .messages import message_to_json_bytes
 from .util import describe_request
 
 if TYPE_CHECKING:
@@ -94,7 +95,7 @@ class WebSocketHandler:
         # to where messages are queued. This allows the implementation
         # to use a deque and an asyncio.Future to avoid the overhead of
         # an asyncio.Queue.
-        self._message_queue: deque[str | None] = deque()
+        self._message_queue: deque[bytes | None] = deque()
         self._ready_future: asyncio.Future[None] | None = None
 
     def __repr__(self) -> str:
@@ -121,7 +122,10 @@ class WebSocketHandler:
         message_queue = self._message_queue
         logger = self._logger
         wsock = self._wsock
-        send_str = wsock.send_str
+        writer = wsock._writer  # pylint: disable=protected-access
+        if TYPE_CHECKING:
+            assert writer is not None
+        send_str = partial(writer.send, binary=False)
         loop = self._hass.loop
         debug = logger.debug
         is_enabled_for = logger.isEnabledFor
@@ -151,7 +155,7 @@ class WebSocketHandler:
                     await send_str(message)
                     continue
 
-                messages: list[str] = [message]
+                messages: list[bytes] = [message]
                 while messages_remaining:
                     # A None message is used to signal the end of the connection
                     if (message := message_queue.popleft()) is None:
@@ -159,7 +163,7 @@ class WebSocketHandler:
                     messages.append(message)
                     messages_remaining -= 1
 
-                coalesced_messages = f'[{",".join(messages)}]'
+                coalesced_messages = b"".join((b"[", b",".join(messages), b"]"))
                 if debug_enabled:
                     debug("%s: Sending %s", self.description, coalesced_messages)
                 await send_str(coalesced_messages)
@@ -181,7 +185,7 @@ class WebSocketHandler:
             self._peak_checker_unsub = None
 
     @callback
-    def _send_message(self, message: str | dict[str, Any]) -> None:
+    def _send_message(self, message: str | bytes | dict[str, Any]) -> None:
         """Send a message to the client.
 
         Closes connection if the client is not reading the messages.
@@ -194,7 +198,9 @@ class WebSocketHandler:
             return
 
         if isinstance(message, dict):
-            message = message_to_json(message)
+            message = message_to_json_bytes(message)
+        elif isinstance(message, str):
+            message = message.encode("utf-8")
 
         message_queue = self._message_queue
         queue_size_before_add = len(message_queue)
diff --git a/homeassistant/components/websocket_api/messages.py b/homeassistant/components/websocket_api/messages.py
index 55144217fdc..3916cdd3af7 100644
--- a/homeassistant/components/websocket_api/messages.py
+++ b/homeassistant/components/websocket_api/messages.py
@@ -16,7 +16,11 @@ from homeassistant.const import (
 )
 from homeassistant.core import Event, State
 from homeassistant.helpers import config_validation as cv
-from homeassistant.helpers.json import JSON_DUMP, find_paths_unserializable_data
+from homeassistant.helpers.json import (
+    JSON_DUMP,
+    find_paths_unserializable_data,
+    json_bytes,
+)
 from homeassistant.util.json import format_unserializable_data
 
 from . import const
@@ -44,7 +48,7 @@ BASE_ERROR_MESSAGE = {
     "success": False,
 }
 
-INVALID_JSON_PARTIAL_MESSAGE = JSON_DUMP(
+INVALID_JSON_PARTIAL_MESSAGE = json_bytes(
     {
         **BASE_ERROR_MESSAGE,
         "error": {
@@ -60,9 +64,17 @@ def result_message(iden: int, result: Any = None) -> dict[str, Any]:
     return {"id": iden, "type": const.TYPE_RESULT, "success": True, "result": result}
 
 
-def construct_result_message(iden: int, payload: str) -> str:
+def construct_result_message(iden: int, payload: bytes) -> bytes:
     """Construct a success result message JSON."""
-    return f'{{"id":{iden},"type":"result","success":true,"result":{payload}}}'
+    return b"".join(
+        (
+            b'{"id":',
+            str(iden).encode(),
+            b',"type":"result","success":true,"result":',
+            payload,
+            b"}",
+        )
+    )
 
 
 def error_message(
@@ -96,7 +108,7 @@ def event_message(iden: int, event: Any) -> dict[str, Any]:
     return {"id": iden, "type": "event", "event": event}
 
 
-def cached_event_message(iden: int, event: Event) -> str:
+def cached_event_message(iden: int, event: Event) -> bytes:
     """Return an event message.
 
     Serialize to json once per message.
@@ -105,23 +117,30 @@ def cached_event_message(iden: int, event: Event) -> str:
     all getting many of the same events (mostly state changed)
     we can avoid serializing the same data for each connection.
     """
-    return f'{_partial_cached_event_message(event)[:-1]},"id":{iden}}}'
+    return b"".join(
+        (
+            _partial_cached_event_message(event)[:-1],
+            b',"id":',
+            str(iden).encode(),
+            b"}",
+        )
+    )
 
 
 @lru_cache(maxsize=128)
-def _partial_cached_event_message(event: Event) -> str:
+def _partial_cached_event_message(event: Event) -> bytes:
     """Cache and serialize the event to json.
 
     The message is constructed without the id which appended
     in cached_event_message.
     """
     return (
-        _message_to_json_or_none({"type": "event", "event": event.json_fragment})
+        _message_to_json_bytes_or_none({"type": "event", "event": event.json_fragment})
         or INVALID_JSON_PARTIAL_MESSAGE
     )
 
 
-def cached_state_diff_message(iden: int, event: Event) -> str:
+def cached_state_diff_message(iden: int, event: Event) -> bytes:
     """Return an event message.
 
     Serialize to json once per message.
@@ -130,18 +149,27 @@ def cached_state_diff_message(iden: int, event: Event) -> str:
     all getting many of the same events (mostly state changed)
     we can avoid serializing the same data for each connection.
     """
-    return f'{_partial_cached_state_diff_message(event)[:-1]},"id":{iden}}}'
+    return b"".join(
+        (
+            _partial_cached_state_diff_message(event)[:-1],
+            b',"id":',
+            str(iden).encode(),
+            b"}",
+        )
+    )
 
 
 @lru_cache(maxsize=128)
-def _partial_cached_state_diff_message(event: Event) -> str:
+def _partial_cached_state_diff_message(event: Event) -> bytes:
     """Cache and serialize the event to json.
 
     The message is constructed without the id which
     will be appended in cached_state_diff_message
     """
     return (
-        _message_to_json_or_none({"type": "event", "event": _state_diff_event(event)})
+        _message_to_json_bytes_or_none(
+            {"type": "event", "event": _state_diff_event(event)}
+        )
         or INVALID_JSON_PARTIAL_MESSAGE
     )
 
@@ -212,10 +240,10 @@ def _state_diff(
     return {ENTITY_EVENT_CHANGE: {new_state.entity_id: diff}}
 
 
-def _message_to_json_or_none(message: dict[str, Any]) -> str | None:
+def _message_to_json_bytes_or_none(message: dict[str, Any]) -> bytes | None:
     """Serialize a websocket message to json or return None."""
     try:
-        return JSON_DUMP(message)
+        return json_bytes(message)
     except (ValueError, TypeError):
         _LOGGER.error(
             "Unable to serialize to JSON. Bad data found at %s",
@@ -226,9 +254,9 @@ def _message_to_json_or_none(message: dict[str, Any]) -> str | None:
     return None
 
 
-def message_to_json(message: dict[str, Any]) -> str:
+def message_to_json_bytes(message: dict[str, Any]) -> bytes:
     """Serialize a websocket message to json or return an error."""
-    return _message_to_json_or_none(message) or JSON_DUMP(
+    return _message_to_json_bytes_or_none(message) or json_bytes(
         error_message(
             message["id"], const.ERR_UNKNOWN_ERROR, "Invalid JSON in response"
         )
diff --git a/homeassistant/core.py b/homeassistant/core.py
index e65273538a8..9c9ca335602 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -86,7 +86,7 @@ from .helpers.deprecation import (
     check_if_deprecated_constant,
     dir_with_deprecated_constants,
 )
-from .helpers.json import json_dumps, json_fragment
+from .helpers.json import json_bytes, json_fragment
 from .util import dt as dt_util, location
 from .util.async_ import (
     cancelling,
@@ -1039,7 +1039,7 @@ class Context:
     @cached_property
     def json_fragment(self) -> json_fragment:
         """Return a JSON fragment of the context."""
-        return json_fragment(json_dumps(self._as_dict))
+        return json_fragment(json_bytes(self._as_dict))
 
 
 class EventOrigin(enum.Enum):
@@ -1126,7 +1126,7 @@ class Event:
     @cached_property
     def json_fragment(self) -> json_fragment:
         """Return an event as a JSON fragment."""
-        return json_fragment(json_dumps(self._as_dict))
+        return json_fragment(json_bytes(self._as_dict))
 
     def __repr__(self) -> str:
         """Return the representation."""
@@ -1512,9 +1512,9 @@ class State:
         return ReadOnlyDict(as_dict)
 
     @cached_property
-    def as_dict_json(self) -> str:
+    def as_dict_json(self) -> bytes:
         """Return a JSON string of the State."""
-        return json_dumps(self._as_dict)
+        return json_bytes(self._as_dict)
 
     @cached_property
     def json_fragment(self) -> json_fragment:
@@ -1550,14 +1550,14 @@ class State:
         return compressed_state
 
     @cached_property
-    def as_compressed_state_json(self) -> str:
+    def as_compressed_state_json(self) -> bytes:
         """Build a compressed JSON key value pair of a state for adds.
 
         The JSON string is a key value pair of the entity_id and the compressed state.
 
         It is used for sending multiple states in a single message.
         """
-        return json_dumps({self.entity_id: self.as_compressed_state})[1:-1]
+        return json_bytes({self.entity_id: self.as_compressed_state})[1:-1]
 
     @classmethod
     def from_dict(cls, json_dict: dict[str, Any]) -> Self | None:
diff --git a/homeassistant/helpers/device_registry.py b/homeassistant/helpers/device_registry.py
index cfe3b78ebab..52e779a3608 100644
--- a/homeassistant/helpers/device_registry.py
+++ b/homeassistant/helpers/device_registry.py
@@ -29,7 +29,7 @@ from .deprecation import (
     dir_with_deprecated_constants,
 )
 from .frame import report
-from .json import JSON_DUMP, find_paths_unserializable_data
+from .json import JSON_DUMP, find_paths_unserializable_data, json_bytes
 from .typing import UNDEFINED, UndefinedType
 
 if TYPE_CHECKING:
@@ -277,11 +277,11 @@ class DeviceEntry:
         }
 
     @cached_property
-    def json_repr(self) -> str | None:
+    def json_repr(self) -> bytes | None:
         """Return a cached JSON representation of the entry."""
         try:
             dict_repr = self.dict_repr
-            return JSON_DUMP(dict_repr)
+            return json_bytes(dict_repr)
         except (ValueError, TypeError):
             _LOGGER.error(
                 "Unable to serialize entry %s to JSON. Bad data found at %s",
diff --git a/homeassistant/helpers/entity_registry.py b/homeassistant/helpers/entity_registry.py
index 1f9da1969f2..049d136ed72 100644
--- a/homeassistant/helpers/entity_registry.py
+++ b/homeassistant/helpers/entity_registry.py
@@ -51,7 +51,7 @@ from homeassistant.util.read_only_dict import ReadOnlyDict
 
 from . import device_registry as dr, storage
 from .device_registry import EVENT_DEVICE_REGISTRY_UPDATED
-from .json import JSON_DUMP, find_paths_unserializable_data
+from .json import JSON_DUMP, find_paths_unserializable_data, json_bytes
 from .typing import UNDEFINED, UndefinedType
 
 if TYPE_CHECKING:
@@ -227,14 +227,14 @@ class RegistryEntry:
         return display_dict
 
     @cached_property
-    def display_json_repr(self) -> str | None:
+    def display_json_repr(self) -> bytes | None:
         """Return a cached partial JSON representation of the entry.
 
         This version only includes what's needed for display.
         """
         try:
             dict_repr = self._as_display_dict
-            json_repr: str | None = JSON_DUMP(dict_repr) if dict_repr else None
+            json_repr: bytes | None = json_bytes(dict_repr) if dict_repr else None
             return json_repr
         except (ValueError, TypeError):
             _LOGGER.error(
@@ -282,11 +282,11 @@ class RegistryEntry:
         }
 
     @cached_property
-    def partial_json_repr(self) -> str | None:
+    def partial_json_repr(self) -> bytes | None:
         """Return a cached partial JSON representation of the entry."""
         try:
             dict_repr = self.as_partial_dict
-            return JSON_DUMP(dict_repr)
+            return json_bytes(dict_repr)
         except (ValueError, TypeError):
             _LOGGER.error(
                 "Unable to serialize entry %s to JSON. Bad data found at %s",
diff --git a/tests/components/websocket_api/test_messages.py b/tests/components/websocket_api/test_messages.py
index 24387a89a29..5fc0e4ea315 100644
--- a/tests/components/websocket_api/test_messages.py
+++ b/tests/components/websocket_api/test_messages.py
@@ -5,7 +5,7 @@ from homeassistant.components.websocket_api.messages import (
     _partial_cached_event_message as lru_event_cache,
     _state_diff_event,
     cached_event_message,
-    message_to_json,
+    message_to_json_bytes,
 )
 from homeassistant.const import EVENT_STATE_CHANGED
 from homeassistant.core import Context, Event, HomeAssistant, State, callback
@@ -282,18 +282,18 @@ async def test_state_diff_event(hass: HomeAssistant) -> None:
     }
 
 
-async def test_message_to_json(caplog: pytest.LogCaptureFixture) -> None:
+async def test_message_to_json_bytes(caplog: pytest.LogCaptureFixture) -> None:
     """Test we can serialize websocket messages."""
 
-    json_str = message_to_json({"id": 1, "message": "xyz"})
+    json_str = message_to_json_bytes({"id": 1, "message": "xyz"})
 
-    assert json_str == '{"id":1,"message":"xyz"}'
+    assert json_str == b'{"id":1,"message":"xyz"}'
 
-    json_str2 = message_to_json({"id": 1, "message": _Unserializeable()})
+    json_str2 = message_to_json_bytes({"id": 1, "message": _Unserializeable()})
 
     assert (
         json_str2
-        == '{"id":1,"type":"result","success":false,"error":{"code":"unknown_error","message":"Invalid JSON in response"}}'
+        == b'{"id":1,"type":"result","success":false,"error":{"code":"unknown_error","message":"Invalid JSON in response"}}'
     )
     assert "Unable to serialize to JSON" in caplog.text
 
diff --git a/tests/test_core.py b/tests/test_core.py
index c2a5a73e6ee..e6a1362a30e 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -742,9 +742,9 @@ def test_state_as_dict_json() -> None:
         context=ha.Context(id="01H0D6K3RFJAYAV2093ZW30PCW"),
     )
     expected = (
-        '{"entity_id":"happy.happy","state":"on","attributes":{"pig":"dog"},'
-        '"last_changed":"1984-12-08T12:00:00","last_updated":"1984-12-08T12:00:00",'
-        '"context":{"id":"01H0D6K3RFJAYAV2093ZW30PCW","parent_id":null,"user_id":null}}'
+        b'{"entity_id":"happy.happy","state":"on","attributes":{"pig":"dog"},'
+        b'"last_changed":"1984-12-08T12:00:00","last_updated":"1984-12-08T12:00:00",'
+        b'"context":{"id":"01H0D6K3RFJAYAV2093ZW30PCW","parent_id":null,"user_id":null}}'
     )
     as_dict_json_1 = state.as_dict_json
     assert as_dict_json_1 == expected
@@ -852,7 +852,7 @@ def test_state_as_compressed_state_json() -> None:
         last_changed=last_time,
         context=ha.Context(id="01H0D6H5K3SZJ3XGDHED1TJ79N"),
     )
-    expected = '"happy.happy":{"s":"on","a":{"pig":"dog"},"c":"01H0D6H5K3SZJ3XGDHED1TJ79N","lc":471355200.0}'
+    expected = b'"happy.happy":{"s":"on","a":{"pig":"dog"},"c":"01H0D6H5K3SZJ3XGDHED1TJ79N","lc":471355200.0}'
     as_compressed_state = state.as_compressed_state_json
     # We are not too concerned about these being ReadOnlyDict
     # since we don't expect them to be called by external callers