diff --git a/homeassistant/components/websocket_api/__init__.py b/homeassistant/components/websocket_api/__init__.py
index bfcfc796bad..2d591455eaf 100644
--- a/homeassistant/components/websocket_api/__init__.py
+++ b/homeassistant/components/websocket_api/__init__.py
@@ -6,7 +6,31 @@ import voluptuous as vol
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.loader import bind_hass
 
-from . import commands, connection, const, decorators, http, messages
+from . import commands, connection, const, decorators, http, messages  # noqa
+from .connection import ActiveConnection  # noqa
+from .const import (  # noqa
+    ERR_HOME_ASSISTANT_ERROR,
+    ERR_INVALID_FORMAT,
+    ERR_NOT_FOUND,
+    ERR_NOT_SUPPORTED,
+    ERR_TEMPLATE_ERROR,
+    ERR_TIMEOUT,
+    ERR_UNAUTHORIZED,
+    ERR_UNKNOWN_COMMAND,
+    ERR_UNKNOWN_ERROR,
+)
+from .decorators import (  # noqa
+    async_response,
+    require_admin,
+    websocket_command,
+    ws_require_user,
+)
+from .messages import (  # noqa
+    BASE_COMMAND_MESSAGE_SCHEMA,
+    error_message,
+    event_message,
+    result_message,
+)
 
 # mypy: allow-untyped-calls, allow-untyped-defs
 
@@ -14,17 +38,6 @@ DOMAIN = const.DOMAIN
 
 DEPENDENCIES = ("http",)
 
-# Backwards compat / Make it easier to integrate
-ActiveConnection = connection.ActiveConnection
-BASE_COMMAND_MESSAGE_SCHEMA = messages.BASE_COMMAND_MESSAGE_SCHEMA
-error_message = messages.error_message
-result_message = messages.result_message
-event_message = messages.event_message
-async_response = decorators.async_response
-require_admin = decorators.require_admin
-ws_require_user = decorators.ws_require_user
-websocket_command = decorators.websocket_command
-
 
 @bind_hass
 @callback
diff --git a/homeassistant/components/websocket_api/connection.py b/homeassistant/components/websocket_api/connection.py
index ae2bb16c6d2..108d4de5ada 100644
--- a/homeassistant/components/websocket_api/connection.py
+++ b/homeassistant/components/websocket_api/connection.py
@@ -5,7 +5,7 @@ from typing import Any, Callable, Dict, Hashable, Optional
 import voluptuous as vol
 
 from homeassistant.core import Context, callback
-from homeassistant.exceptions import Unauthorized
+from homeassistant.exceptions import HomeAssistantError, Unauthorized
 
 from . import const, messages
 
@@ -118,6 +118,9 @@ class ActiveConnection:
         elif isinstance(err, asyncio.TimeoutError):
             code = const.ERR_TIMEOUT
             err_message = "Timeout"
+        elif isinstance(err, HomeAssistantError):
+            code = const.ERR_UNKNOWN_ERROR
+            err_message = str(err)
         else:
             code = const.ERR_UNKNOWN_ERROR
             err_message = "Unknown error"
diff --git a/tests/components/websocket_api/test_connection.py b/tests/components/websocket_api/test_connection.py
index 5890fc9a2fa..55126ff1333 100644
--- a/tests/components/websocket_api/test_connection.py
+++ b/tests/components/websocket_api/test_connection.py
@@ -1,4 +1,10 @@
 """Test WebSocket Connection class."""
+import asyncio
+import logging
+
+import voluptuous as vol
+
+from homeassistant import exceptions
 from homeassistant.components import websocket_api
 from homeassistant.components.websocket_api import const
 
@@ -20,3 +26,32 @@ async def test_send_big_result(hass, websocket_client):
     assert msg["type"] == const.TYPE_RESULT
     assert msg["success"]
     assert msg["result"] == {"big": "result"}
+
+
+async def test_exception_handling():
+    """Test handling of exceptions."""
+    send_messages = []
+    conn = websocket_api.ActiveConnection(
+        logging.getLogger(__name__), None, send_messages.append, None, None
+    )
+
+    for (exc, code, err) in (
+        (exceptions.Unauthorized(), websocket_api.ERR_UNAUTHORIZED, "Unauthorized"),
+        (
+            vol.Invalid("Invalid something"),
+            websocket_api.ERR_INVALID_FORMAT,
+            "Invalid something. Got {'id': 5}",
+        ),
+        (asyncio.TimeoutError(), websocket_api.ERR_TIMEOUT, "Timeout"),
+        (
+            exceptions.HomeAssistantError("Failed to do X"),
+            websocket_api.ERR_UNKNOWN_ERROR,
+            "Failed to do X",
+        ),
+        (ValueError("Really bad"), websocket_api.ERR_UNKNOWN_ERROR, "Unknown error"),
+    ):
+        send_messages.clear()
+        conn.async_handle_exception({"id": 5}, exc)
+        assert len(send_messages) == 1
+        assert send_messages[0]["error"]["code"] == code
+        assert send_messages[0]["error"]["message"] == err