diff --git a/src/quizzi/application/__main__.py b/src/quizzi/application/__main__.py
index 52df068..1b810b6 100644
--- a/src/quizzi/application/__main__.py
+++ b/src/quizzi/application/__main__.py
@@ -26,7 +26,7 @@ from quizzi.application.bot.user_dialogs.main_menu import user_menu_dialog
 from quizzi.application.bot.user_dialogs.registration import registration_dialog
 from quizzi.application.bot.user_dialogs.take_test import take_test_dialog
 from quizzi.infrastructure.database.repo.user import UserRepository
-from quizzi.infrastructure.di import DatabaseProvider, SchedulerProvider
+from quizzi.infrastructure.di import DatabaseProvider, SchedulerProvider, ServiceProvider
 from quizzi.infrastructure.utils.bot_commands import setup_bot_commands
 from quizzi.infrastructure.utils.config import Config
 
@@ -68,6 +68,7 @@ async def main() -> None:
     
     container = make_async_container(
         DatabaseProvider(),
+        ServiceProvider(),
         SchedulerProvider(),
         context={Bot: bot, Config: config}
     )
diff --git a/src/quizzi/application/bot/handlers.py b/src/quizzi/application/bot/handlers.py
index 4dbff34..dfee906 100644
--- a/src/quizzi/application/bot/handlers.py
+++ b/src/quizzi/application/bot/handlers.py
@@ -10,36 +10,29 @@ from dishka.integrations.aiogram import FromDishka
 from quizzi.application.bot.admin_dialogs.states import AdminMenuSG
 from quizzi.application.bot.creator_dialogs.states import CreatorMenuSG
 from quizzi.application.bot.user_dialogs.states import UserDeeplinkSG, UserMenuSG, UserRegistrationSG
-from quizzi.infrastructure.database.dao.group import GroupDAO
-from quizzi.infrastructure.database.dao.test import TestDAO
-from quizzi.infrastructure.database.dao.user import UserDAO
-from quizzi.infrastructure.utils.config import Config
-from quizzi.infrastructure.utils.test_id_to_hash import decode_id
-from quizzi.infrastructure.utils.timezone import now_msk_naive
+from quizzi.service.test import TestService
+from quizzi.service.user import UserService
 
 router = Router()
 logger = logging.getLogger(__name__)
 
 
 async def ensure_user_registered(
-    user_dao: UserDAO,
-    group_dao: GroupDAO,
+    user_service: UserService,
     message: Message,
     dialog_manager: DialogManager,
     pending_test_id: int | None = None,
 ) -> bool:
     assert message.from_user is not None
     
-    existing_user = await user_dao.get_by_id(message.from_user.id)
-    groups = await group_dao.get_all()
-    has_groups = len(groups) > 0
+    result = await user_service.check_registration(message.from_user.id)
     
-    start_data = {"user_id": message.from_user.id, "has_groups": has_groups}
+    start_data = {"user_id": message.from_user.id, "has_groups": result.has_groups}
     if pending_test_id:
         start_data["pending_test_id"] = pending_test_id
     
-    if existing_user is None:
-        await user_dao.create(
+    if result.user is None:
+        await user_service.create_user(
             user_id=message.from_user.id,
             first_name=message.from_user.first_name,
             username=message.from_user.username,
@@ -52,10 +45,7 @@ async def ensure_user_registered(
         )
         return False
     
-    needs_name = existing_user.name is None
-    needs_group = has_groups and existing_user.group is None
-    
-    if needs_name:
+    if result.needs_name:
         await dialog_manager.start(
             UserRegistrationSG.input_name,
             mode=StartMode.RESET_STACK,
@@ -63,7 +53,7 @@ async def ensure_user_registered(
         )
         return False
     
-    if needs_group:
+    if result.needs_group:
         await dialog_manager.start(
             UserRegistrationSG.select_group,
             mode=StartMode.RESET_STACK,
@@ -71,7 +61,7 @@ async def ensure_user_registered(
         )
         return False
     
-    await user_dao.upsert(
+    await user_service.update_user_info(
         user_id=message.from_user.id,
         first_name=message.from_user.first_name,
         username=message.from_user.username,
@@ -80,39 +70,13 @@ async def ensure_user_registered(
     return True
 
 
-async def validate_deeplink_test(
-    test_dao: TestDAO,
-    user_dao: UserDAO,
-    test_id: int,
-    user_id: int,
-) -> tuple[bool, str]:
-    test = await test_dao.get_by_id(test_id)
-    
-    if not test:
-        return False, "❌ Тест не найден"
-    
-    if not test.is_active:
-        return False, "❌ Тест деактивирован"
-    
-    if test.expires_at and test.expires_at < now_msk_naive():
-        return False, "❌ Срок действия теста истек"
-    
-    user = await user_dao.get_by_id(user_id)
-    if test.for_group and user and user.group != test.for_group:
-        return False, f"❌ Тест доступен только для группы {test.for_group}"
-    
-    return True, ""
-
-
 @router.message(CommandStart(deep_link=True))
 async def start_with_deeplink(
     message: Message,
     command: CommandObject,
     dialog_manager: DialogManager,
-    user_dao: FromDishka[UserDAO],
-    group_dao: FromDishka[GroupDAO],
-    test_dao: FromDishka[TestDAO],
-    config: FromDishka[Config],
+    user_service: FromDishka[UserService],
+    test_service: FromDishka[TestService],
 ) -> None:
     assert message.from_user is not None
     
@@ -125,39 +89,36 @@ async def start_with_deeplink(
     )
     
     if not deeplink:
-        await start_handler(message, user_dao, group_dao, dialog_manager)
+        await start_handler(message, user_service, dialog_manager)
         return
     
-    try:
-        test_id = decode_id(deeplink, config.security.encode_key)
-    except (ValueError, IndexError):
+    test_id = test_service.decode_test_hash(deeplink)
+    if test_id is None:
         logger.warning("Invalid deeplink: user_id=%d, deeplink=%s", message.from_user.id, deeplink)
         await message.answer("❌ Неверная ссылка на тест")
-        await start_handler(message, user_dao, group_dao, dialog_manager)
+        await start_handler(message, user_service, dialog_manager)
         return
     
     is_registered = await ensure_user_registered(
-        user_dao, group_dao, message, dialog_manager, pending_test_id=test_id
+        user_service, message, dialog_manager, pending_test_id=test_id
     )
     
     if not is_registered:
         return
     
-    is_valid, error = await validate_deeplink_test(
-        test_dao, user_dao, test_id, message.from_user.id
-    )
+    validation = await test_service.validate_test(test_id, message.from_user.id)
     
-    if not is_valid:
+    if not validation.is_valid:
         logger.info(
             "Test validation failed: user_id=%d, test_id=%d, error=%s",
             message.from_user.id,
             test_id,
-            error,
+            validation.error,
         )
         await dialog_manager.start(
             UserDeeplinkSG.test_preview,
             mode=StartMode.RESET_STACK,
-            data={"test_id": test_id, "error": error}
+            data={"test_id": test_id, "error": validation.error}
         )
         return
     
@@ -173,8 +134,7 @@ async def start_with_deeplink(
 async def start_handler(
     message: Message,
     dialog_manager: DialogManager,
-    user_dao: FromDishka[UserDAO],
-    group_dao: FromDishka[GroupDAO],
+    user_service: FromDishka[UserService],
 ) -> None:
     assert message.from_user is not None
     logger.info(
@@ -184,7 +144,7 @@ async def start_handler(
     )
     
     is_registered = await ensure_user_registered(
-        user_dao, group_dao, message, dialog_manager
+        user_service, message, dialog_manager
     )
     
     if is_registered:
diff --git a/src/quizzi/application/bot/shared_dialogs/broadcast.py b/src/quizzi/application/bot/shared_dialogs/broadcast.py
index 17006f0..ff4fb4b 100644
--- a/src/quizzi/application/bot/shared_dialogs/broadcast.py
+++ b/src/quizzi/application/bot/shared_dialogs/broadcast.py
@@ -7,8 +7,7 @@ from dishka import FromDishka
 from dishka.integrations.aiogram_dialog import inject
 
 from quizzi.application.bot.shared_dialogs.states import SharedBroadcastSG
-from quizzi.infrastructure.database.dao.user import UserDAO
-from quizzi.infrastructure.utils.broadcast import broadcast_message
+from quizzi.service.broadcast import BroadcastService
 
 
 async def on_broadcast_input(message: Message, _widget: MessageInput, manager: DialogManager):
@@ -18,7 +17,12 @@ async def on_broadcast_input(message: Message, _widget: MessageInput, manager: D
 
 
 @inject
-async def on_broadcast_confirm(_callback: CallbackQuery, _button: Button, manager: DialogManager, user_dao: FromDishka[UserDAO]):
+async def on_broadcast_confirm(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    broadcast_service: FromDishka[BroadcastService],
+):
     message_id = manager.dialog_data.get("broadcast_message_id")
     chat_id = manager.dialog_data.get("broadcast_chat_id")
     
@@ -33,7 +37,7 @@ async def on_broadcast_confirm(_callback: CallbackQuery, _button: Button, manage
         await _callback.answer("Ошибка: бот не найден")
         return
     
-    stats = await broadcast_message(bot, message_id, chat_id, user_dao)
+    stats = await broadcast_service.broadcast_message(bot, message_id, chat_id)
     
     stats_text = (
         f"✅ <b>Рассылка завершена</b>\n\n"
diff --git a/src/quizzi/application/bot/shared_dialogs/tests.py b/src/quizzi/application/bot/shared_dialogs/tests.py
index 12d2c97..288adef 100644
--- a/src/quizzi/application/bot/shared_dialogs/tests.py
+++ b/src/quizzi/application/bot/shared_dialogs/tests.py
@@ -1,6 +1,5 @@
 import asyncio
 import functools
-import io
 from datetime import date, datetime, time
 
 from aiogram import Bot
@@ -11,18 +10,16 @@ from aiogram_dialog.widgets.kbd import Button, Calendar, Column, Row, ScrollingG
 from aiogram_dialog.widgets.text import Const, Format
 from dishka import FromDishka
 from dishka.integrations.aiogram_dialog import inject
-from openpyxl import Workbook
-from openpyxl.styles import Alignment, Border, Font, PatternFill, Side
 
 from quizzi.application.bot.shared_dialogs.states import SharedCreateTestSG, SharedTestsSG
 from quizzi.infrastructure.database.dao.group import GroupDAO
 from quizzi.infrastructure.database.dao.test import TestDAO
 from quizzi.infrastructure.database.repo.test import TestRepository
 from quizzi.infrastructure.database.repo.test_attempt import TestAttemptRepository
-from quizzi.infrastructure.utils.config import Config
 from quizzi.infrastructure.utils.qr_generator import generate_qr_bytes
-from quizzi.infrastructure.utils.test_id_to_hash import encode_id
 from quizzi.infrastructure.utils.timezone import to_msk
+from quizzi.service.excel import ExcelService
+from quizzi.service.test import TestService
 
 
 @inject
@@ -101,34 +98,38 @@ async def get_test_detail(test_dao: FromDishka[TestDAO], test_repo: FromDishka[T
 
 
 @inject
-async def on_toggle_active(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_toggle_active(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    test = await test_dao.get_by_id(test_id)
-    
-    if test:
-        await test_dao.update(test_id, is_active=not test.is_active)
-        action = "деактивирован" if test.is_active else "активирован"
-        await _callback.answer(f"✅ Тест {action}")
+    result = await test_service.toggle_test_active(test_id)
+    await _callback.answer(result.message)
+    if result.success:
         await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_toggle_results_viewable(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_toggle_results_viewable(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    test = await test_dao.get_by_id(test_id)
-    
-    if test:
-        await test_dao.update(test_id, are_results_viewable=not test.are_results_viewable)
-        action = "скрыты" if test.are_results_viewable else "видны"
-        await _callback.answer(f"✅ Результаты теперь {action}")
+    result = await test_service.toggle_results_viewable(test_id)
+    await _callback.answer(result.message)
+    if result.success:
         await manager.switch_to(SharedTestsSG.test_detail)
 
 
@@ -235,7 +236,13 @@ async def on_export_stats(_callback: CallbackQuery, _button: Button, manager: Di
 
 
 @inject
-async def on_share_test(_callback: CallbackQuery, _button: Button, manager: DialogManager, config: FromDishka[Config], bot_inst: FromDishka[Bot]):
+async def on_share_test(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+    bot_inst: FromDishka[Bot],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     
     if not test_id:
@@ -243,11 +250,7 @@ async def on_share_test(_callback: CallbackQuery, _button: Button, manager: Dial
             "share_link": "Ошибка: тест не найден"
         }
     
-    test_hash = encode_id(
-        test_id, 
-        config.security.encode_key,
-        config.security.encoded_string_length
-    )
+    test_hash = test_service.encode_test_id(test_id)
     
     bot_info = await bot_inst.get_me()
     bot_username = bot_info.username or "your_bot"
@@ -314,13 +317,18 @@ async def get_delete_confirm_data(dialog_manager: DialogManager, test_dao: FromD
 
 
 @inject
-async def on_confirm_delete(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_confirm_delete(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    deleted = await test_dao.delete(test_id)
+    deleted = await test_service.delete_test(test_id)
     if deleted:
         await _callback.answer("✅ Тест удалён")
         await manager.switch_to(SharedTestsSG.tests_list)
@@ -329,7 +337,12 @@ async def on_confirm_delete(_callback: CallbackQuery, _button: Button, manager:
 
 
 @inject
-async def on_password_input(message: Message, _widget: MessageInput, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_password_input(
+    message: Message,
+    _widget: MessageInput,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await message.answer("❌ Тест не найден")
@@ -339,30 +352,36 @@ async def on_password_input(message: Message, _widget: MessageInput, manager: Di
         await message.answer("❌ Пароль не может быть пустым")
         return
     
-    password = message.text.strip()
-    if len(password) > 255:
-        await message.answer("❌ Пароль слишком длинный (максимум 255 символов)")
-        return
-    
-    await test_dao.update(test_id, password=password)
-    await message.answer("✅ Пароль обновлен")
-    await manager.switch_to(SharedTestsSG.test_detail)
+    result = await test_service.update_password(test_id, message.text.strip())
+    await message.answer(result.message)
+    if result.success:
+        await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_remove_password(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_remove_password(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    await test_dao.update(test_id, password=None)
-    await _callback.answer("✅ Пароль удален")
+    result = await test_service.remove_password(test_id)
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_attempts_input_edit(message: Message, _widget: MessageInput, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_attempts_input_edit(
+    message: Message,
+    _widget: MessageInput,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await message.answer("❌ Тест не найден")
@@ -373,40 +392,40 @@ async def on_attempts_input_edit(message: Message, _widget: MessageInput, manage
         return
     
     attempts_str = message.text.strip()
-    
     if not attempts_str.isdigit():
         await message.answer("❌ Количество попыток должно быть числом")
         return
     
-    attempts = int(attempts_str)
-    
-    if attempts < 1:
-        await message.answer("❌ Количество попыток должно быть больше 0")
-        return
-    
-    if attempts > 100:
-        await message.answer("❌ Количество попыток не может быть больше 100")
-        return
-    
-    await test_dao.update(test_id, attempts=attempts)
-    await message.answer("✅ Количество попыток обновлено")
-    await manager.switch_to(SharedTestsSG.test_detail)
+    result = await test_service.update_attempts(test_id, int(attempts_str))
+    await message.answer(result.message)
+    if result.success:
+        await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_remove_attempts(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_remove_attempts(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    await test_dao.update(test_id, attempts=None)
-    await _callback.answer("✅ Ограничение попыток удалено")
+    result = await test_service.remove_attempts(test_id)
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_time_limit_input(message: Message, _widget: MessageInput, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_time_limit_input(
+    message: Message,
+    _widget: MessageInput,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await message.answer("❌ Тест не найден")
@@ -417,36 +436,30 @@ async def on_time_limit_input(message: Message, _widget: MessageInput, manager:
         return
     
     time_limit_str = message.text.strip()
-    
     if not time_limit_str.isdigit():
         await message.answer("❌ Лимит времени должен быть числом (в минутах)")
         return
     
-    time_limit_minutes = int(time_limit_str)
-    
-    if time_limit_minutes < 1:
-        await message.answer("❌ Лимит времени должен быть больше 0")
-        return
-    
-    if time_limit_minutes > 1440:
-        await message.answer("❌ Лимит времени не может быть больше 1440 минут (24 часа)")
-        return
-    
-    time_limit_seconds = time_limit_minutes * 60
-    await test_dao.update(test_id, time_limit=time_limit_seconds)
-    await message.answer("✅ Лимит времени обновлен")
-    await manager.switch_to(SharedTestsSG.test_detail)
+    result = await test_service.update_time_limit(test_id, int(time_limit_str))
+    await message.answer(result.message)
+    if result.success:
+        await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_remove_time_limit(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_remove_time_limit(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    await test_dao.update(test_id, time_limit=None)
-    await _callback.answer("✅ Лимит времени удален")
+    result = await test_service.remove_time_limit(test_id)
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
@@ -460,51 +473,73 @@ async def get_groups_for_edit(dialog_manager: DialogManager, group_dao: FromDish
 
 
 @inject
-async def on_group_selected_for_test(_callback: CallbackQuery, _widget, manager: DialogManager, item_id: str, test_dao: FromDishka[TestDAO]):
+async def on_group_selected_for_test(
+    _callback: CallbackQuery,
+    _widget,
+    manager: DialogManager,
+    item_id: str,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    await test_dao.update(test_id, for_group=int(item_id))
-    await _callback.answer("✅ Группа обновлена")
+    result = await test_service.update_group(test_id, int(item_id))
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_remove_group(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_remove_group(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    await test_dao.update(test_id, for_group=None)
-    await _callback.answer("✅ Тест теперь доступен для всех групп")
+    result = await test_service.remove_group(test_id)
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_date_selected_for_test(_callback, _widget, manager: DialogManager, selected_date: date, test_dao: FromDishka[TestDAO]):
+async def on_date_selected_for_test(
+    _callback,
+    _widget,
+    manager: DialogManager,
+    selected_date: date,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
     expires_at = datetime.combine(selected_date, time.min)
-    await test_dao.update(test_id, expires_at=expires_at)
-    await _callback.answer("✅ Срок действия обновлен")
+    result = await test_service.update_expires(test_id, expires_at)
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
 @inject
-async def on_remove_expires(_callback: CallbackQuery, _button: Button, manager: DialogManager, test_dao: FromDishka[TestDAO]):
+async def on_remove_expires(
+    _callback: CallbackQuery,
+    _button: Button,
+    manager: DialogManager,
+    test_service: FromDishka[TestService],
+):
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
         await _callback.answer("❌ Тест не найден")
         return
     
-    await test_dao.update(test_id, expires_at=None)
-    await _callback.answer("✅ Срок действия удален")
+    result = await test_service.remove_expires(test_id)
+    await _callback.answer(result.message)
     await manager.switch_to(SharedTestsSG.test_detail)
 
 
@@ -525,115 +560,13 @@ async def get_groups_for_export(dialog_manager: DialogManager, group_dao: FromDi
     }
 
 
-def create_excel_report(
-    test_title: str,
-    group_number: int,
-    stats: list[tuple[str, int | None, datetime | None, bool | None]],
-) -> bytes:
-    wb = Workbook()
-    ws = wb.active
-    assert ws is not None
-    ws.title = "Статистика"
-    
-    header_font = Font(bold=True, color="FFFFFF")
-    header_fill = PatternFill(start_color="4472C4", end_color="4472C4", fill_type="solid")
-    header_alignment = Alignment(horizontal="center", vertical="center")
-    thin_border = Border(
-        left=Side(style="thin"),
-        right=Side(style="thin"),
-        top=Side(style="thin"),
-        bottom=Side(style="thin"),
-    )
-    
-    ws.merge_cells("A1:E1")
-    ws["A1"] = f"Тест: {test_title}"
-    ws["A1"].font = Font(bold=True, size=14)
-    ws["A1"].alignment = Alignment(horizontal="center")
-    
-    ws.merge_cells("A2:E2")
-    ws["A2"] = f"Группа: {group_number}"
-    ws["A2"].font = Font(bold=True, size=12)
-    ws["A2"].alignment = Alignment(horizontal="center")
-    
-    headers = ["ФИО", "Результат (%)", "Оценка", "Дата прохождения", "Статус"]
-    for col, header in enumerate(headers, 1):
-        cell = ws.cell(row=4, column=col, value=header)
-        cell.font = header_font
-        cell.fill = header_fill
-        cell.alignment = header_alignment
-        cell.border = thin_border
-    
-    passed_fill = PatternFill(start_color="C6EFCE", end_color="C6EFCE", fill_type="solid")
-    failed_fill = PatternFill(start_color="FFC7CE", end_color="FFC7CE", fill_type="solid")
-    not_passed_fill = PatternFill(start_color="FFEB9C", end_color="FFEB9C", fill_type="solid")
-    
-    grades: list[int] = []
-    
-    for row_idx, (name, score, finished_at, is_passed) in enumerate(stats, 5):
-        ws.cell(row=row_idx, column=1, value=name).border = thin_border
-        
-        if score is not None:
-            ws.cell(row=row_idx, column=2, value=score).border = thin_border
-            
-            grade = score // 10
-            grades.append(grade)
-            ws.cell(row=row_idx, column=3, value=grade).border = thin_border
-            
-            finished_msk = to_msk(finished_at) if finished_at else None
-            date_str = finished_msk.strftime("%d.%m.%Y %H:%M") if finished_msk else "—"
-            ws.cell(row=row_idx, column=4, value=date_str).border = thin_border
-            status = "Пройден" if is_passed else "Не пройден"
-            status_cell = ws.cell(row=row_idx, column=5, value=status)
-            status_cell.border = thin_border
-            
-            for col in range(1, 6):
-                ws.cell(row=row_idx, column=col).fill = passed_fill if is_passed else failed_fill
-        else:
-            ws.cell(row=row_idx, column=2, value="—").border = thin_border
-            ws.cell(row=row_idx, column=3, value="—").border = thin_border
-            ws.cell(row=row_idx, column=4, value="—").border = thin_border
-            status_cell = ws.cell(row=row_idx, column=5, value="Не проходил")
-            status_cell.border = thin_border
-            
-            for col in range(1, 6):
-                ws.cell(row=row_idx, column=col).fill = not_passed_fill
-    
-    ws.column_dimensions["A"].width = 30
-    ws.column_dimensions["B"].width = 15
-    ws.column_dimensions["C"].width = 10
-    ws.column_dimensions["D"].width = 20
-    ws.column_dimensions["E"].width = 15
-    
-    total_users = len(stats)
-    passed_users = sum(1 for _, score, _, is_passed in stats if score is not None and is_passed)
-    attempted_users = sum(1 for _, score, _, _ in stats if score is not None)
-    
-    summary_row = len(stats) + 6
-    ws.cell(row=summary_row, column=1, value="Итого:").font = Font(bold=True)
-    ws.cell(row=summary_row + 1, column=1, value=f"Всего студентов: {total_users}")
-    ws.cell(row=summary_row + 2, column=1, value=f"Прошли тест: {attempted_users}")
-    ws.cell(row=summary_row + 3, column=1, value=f"Сдали: {passed_users}")
-    if attempted_users > 0:
-        success_rate = round(passed_users / attempted_users * 100)
-        ws.cell(row=summary_row + 4, column=1, value=f"Процент сдачи: {success_rate}%")
-    if grades:
-        avg_grade = round(sum(grades) / len(grades), 1)
-        ws.cell(row=summary_row + 5, column=1, value=f"Средняя оценка: {avg_grade}")
-    
-    output = io.BytesIO()
-    wb.save(output)
-    output.seek(0)
-    return output.read()
-
-
 @inject
 async def on_group_selected_for_export(
     _callback: CallbackQuery,
     _widget: Select,
     manager: DialogManager,
     item_id: str,
-    test_dao: FromDishka[TestDAO],
-    attempt_repo: FromDishka[TestAttemptRepository],
+    excel_service: FromDishka[ExcelService],
 ) -> None:
     test_id = manager.dialog_data.get("selected_test_id")
     if not test_id:
@@ -643,26 +576,16 @@ async def on_group_selected_for_export(
     assert _callback.message is not None
     await _callback.answer("⏳ Формирую отчёт...")
     
-    test = await test_dao.get_by_id(test_id)
-    if not test:
-        await _callback.message.answer("❌ Тест не найден")
-        return
-    
     group_number = int(item_id)
-    stats = await attempt_repo.get_group_test_statistics(test_id, group_number)
+    result = await excel_service.generate_group_report(test_id, group_number)
     
-    if not stats:
-        await _callback.message.answer(f"❌ В группе {group_number} нет студентов")
+    if not result.success or not result.data or not result.filename:
+        await _callback.message.answer(result.caption)
         return
     
-    excel_bytes = create_excel_report(test.title, group_number, stats)
-    
-    safe_title = "".join(c if c.isalnum() or c in "-_" else "_" for c in test.title)[:30]
-    filename = f"{safe_title}_group_{group_number}.xlsx"
-    
     await _callback.message.answer_document(
-        document=BufferedInputFile(excel_bytes, filename=filename),
-        caption=f"📊 <b>Статистика по тесту</b>\n\n📝 {test.title}\n🎓 Группа {group_number}",
+        document=BufferedInputFile(result.data, filename=result.filename),
+        caption=result.caption,
     )
 
 
diff --git a/src/quizzi/infrastructure/di.py b/src/quizzi/infrastructure/di.py
index 3d6d39a..35e4386 100644
--- a/src/quizzi/infrastructure/di.py
+++ b/src/quizzi/infrastructure/di.py
@@ -20,6 +20,11 @@ from quizzi.infrastructure.database.repo.user import UserRepository
 from quizzi.infrastructure.scheduling.tasks import deactivate_expired_tests, finish_expired_test_attempts, send_time_warning_notifications
 from quizzi.infrastructure.utils.config import Config
 from quizzi.infrastructure.utils.rate_limiter import PasswordRateLimiter
+from quizzi.service.broadcast import BroadcastService
+from quizzi.service.excel import ExcelService
+from quizzi.service.test import TestService
+from quizzi.service.test_attempt import TestAttemptService
+from quizzi.service.user import UserService
 
 
 class DatabaseProvider(Provider):
@@ -80,6 +85,41 @@ class DatabaseProvider(Provider):
         return TestAttemptRepository(session)
 
 
+class ServiceProvider(Provider):
+    @provide(scope=Scope.REQUEST)
+    def get_user_service(self, user_dao: UserDAO, group_dao: GroupDAO) -> UserService:
+        return UserService(user_dao, group_dao)
+    
+    @provide(scope=Scope.REQUEST)
+    def get_test_service(
+        self,
+        test_dao: TestDAO,
+        test_repo: TestRepository,
+        attempt_repo: TestAttemptRepository,
+        user_dao: UserDAO,
+        config: Config,
+    ) -> TestService:
+        return TestService(test_dao, test_repo, attempt_repo, user_dao, config)
+    
+    @provide(scope=Scope.REQUEST)
+    def get_test_attempt_service(
+        self,
+        test_dao: TestDAO,
+        test_repo: TestRepository,
+        attempt_repo: TestAttemptRepository,
+        answer_dao: UserAnswerDAO,
+    ) -> TestAttemptService:
+        return TestAttemptService(test_dao, test_repo, attempt_repo, answer_dao)
+    
+    @provide(scope=Scope.REQUEST)
+    def get_broadcast_service(self, user_dao: UserDAO) -> BroadcastService:
+        return BroadcastService(user_dao)
+    
+    @provide(scope=Scope.REQUEST)
+    def get_excel_service(self, test_dao: TestDAO, attempt_repo: TestAttemptRepository) -> ExcelService:
+        return ExcelService(test_dao, attempt_repo)
+
+
 class SchedulerProvider(Provider):
     @provide(scope = Scope.APP)
     def get_scheduler(self, container: AsyncContainer, bot: Bot) -> AsyncIOScheduler:
diff --git a/src/quizzi/service/__init__.py b/src/quizzi/service/__init__.py
new file mode 100644
index 0000000..7721cac
--- /dev/null
+++ b/src/quizzi/service/__init__.py
@@ -0,0 +1 @@
+# Service layer - бизнес-логика приложения
diff --git a/src/quizzi/service/broadcast.py b/src/quizzi/service/broadcast.py
new file mode 100644
index 0000000..ab8bcf2
--- /dev/null
+++ b/src/quizzi/service/broadcast.py
@@ -0,0 +1,43 @@
+from dataclasses import dataclass
+
+from aiogram import Bot
+from aiogram.exceptions import TelegramAPIError
+
+from quizzi.infrastructure.database.dao.user import UserDAO
+
+
+@dataclass
+class BroadcastStats:
+    total: int
+    success: int
+    failed: int
+
+
+class BroadcastService:
+    def __init__(self, user_dao: UserDAO) -> None:
+        self._user_dao = user_dao
+    
+    async def broadcast_message(
+        self,
+        bot: Bot,
+        message_id: int,
+        from_chat_id: int,
+    ) -> BroadcastStats:
+        users = await self._user_dao.get_all()
+        
+        total = len(users)
+        success = 0
+        failed = 0
+        
+        for user in users:
+            try:
+                await bot.copy_message(
+                    chat_id=user.id,
+                    from_chat_id=from_chat_id,
+                    message_id=message_id,
+                )
+                success += 1
+            except TelegramAPIError:
+                failed += 1
+        
+        return BroadcastStats(total=total, success=success, failed=failed)
diff --git a/src/quizzi/service/excel.py b/src/quizzi/service/excel.py
new file mode 100644
index 0000000..64ca8be
--- /dev/null
+++ b/src/quizzi/service/excel.py
@@ -0,0 +1,145 @@
+import io
+from dataclasses import dataclass
+from datetime import datetime
+
+from openpyxl import Workbook
+from openpyxl.styles import Alignment, Border, Font, PatternFill, Side
+
+from quizzi.infrastructure.database.dao.test import TestDAO
+from quizzi.infrastructure.database.repo.test_attempt import TestAttemptRepository
+from quizzi.infrastructure.utils.timezone import to_msk
+
+
+@dataclass
+class ExcelReportResult:
+    success: bool
+    data: bytes | None = None
+    filename: str | None = None
+    caption: str = ""
+
+
+class ExcelService:
+    def __init__(self, test_dao: TestDAO, attempt_repo: TestAttemptRepository) -> None:
+        self._test_dao = test_dao
+        self._attempt_repo = attempt_repo
+    
+    def create_test_report(
+        self,
+        test_title: str,
+        group_number: int,
+        stats: list[tuple[str, int | None, datetime | None, bool | None]],
+    ) -> bytes:
+        wb = Workbook()
+        ws = wb.active
+        assert ws is not None
+        ws.title = "Статистика"
+        
+        header_font = Font(bold=True, color="FFFFFF")
+        header_fill = PatternFill(start_color="4472C4", end_color="4472C4", fill_type="solid")
+        header_alignment = Alignment(horizontal="center", vertical="center")
+        thin_border = Border(
+            left=Side(style="thin"),
+            right=Side(style="thin"),
+            top=Side(style="thin"),
+            bottom=Side(style="thin"),
+        )
+        
+        ws.merge_cells("A1:E1")
+        ws["A1"] = f"Тест: {test_title}"
+        ws["A1"].font = Font(bold=True, size=14)
+        ws["A1"].alignment = Alignment(horizontal="center")
+        
+        ws.merge_cells("A2:E2")
+        ws["A2"] = f"Группа: {group_number}"
+        ws["A2"].font = Font(bold=True, size=12)
+        ws["A2"].alignment = Alignment(horizontal="center")
+        
+        headers = ["ФИО", "Результат (%)", "Оценка", "Дата прохождения", "Статус"]
+        for col, header in enumerate(headers, 1):
+            cell = ws.cell(row=4, column=col, value=header)
+            cell.font = header_font
+            cell.fill = header_fill
+            cell.alignment = header_alignment
+            cell.border = thin_border
+        
+        passed_fill = PatternFill(start_color="C6EFCE", end_color="C6EFCE", fill_type="solid")
+        failed_fill = PatternFill(start_color="FFC7CE", end_color="FFC7CE", fill_type="solid")
+        not_passed_fill = PatternFill(start_color="FFEB9C", end_color="FFEB9C", fill_type="solid")
+        
+        grades: list[int] = []
+        
+        for row_idx, (name, score, finished_at, is_passed) in enumerate(stats, 5):
+            ws.cell(row=row_idx, column=1, value=name).border = thin_border
+            
+            if score is not None:
+                ws.cell(row=row_idx, column=2, value=score).border = thin_border
+                
+                grade = score // 10
+                grades.append(grade)
+                ws.cell(row=row_idx, column=3, value=grade).border = thin_border
+                
+                finished_msk = to_msk(finished_at) if finished_at else None
+                date_str = finished_msk.strftime("%d.%m.%Y %H:%M") if finished_msk else "—"
+                ws.cell(row=row_idx, column=4, value=date_str).border = thin_border
+                status = "Пройден" if is_passed else "Не пройден"
+                status_cell = ws.cell(row=row_idx, column=5, value=status)
+                status_cell.border = thin_border
+                
+                for col in range(1, 6):
+                    ws.cell(row=row_idx, column=col).fill = passed_fill if is_passed else failed_fill
+            else:
+                ws.cell(row=row_idx, column=2, value="—").border = thin_border
+                ws.cell(row=row_idx, column=3, value="—").border = thin_border
+                ws.cell(row=row_idx, column=4, value="—").border = thin_border
+                status_cell = ws.cell(row=row_idx, column=5, value="Не проходил")
+                status_cell.border = thin_border
+                
+                for col in range(1, 6):
+                    ws.cell(row=row_idx, column=col).fill = not_passed_fill
+        
+        ws.column_dimensions["A"].width = 30
+        ws.column_dimensions["B"].width = 15
+        ws.column_dimensions["C"].width = 10
+        ws.column_dimensions["D"].width = 20
+        ws.column_dimensions["E"].width = 15
+        
+        total_users = len(stats)
+        passed_users = sum(1 for _, score, _, is_passed in stats if score is not None and is_passed)
+        attempted_users = sum(1 for _, score, _, _ in stats if score is not None)
+        
+        summary_row = len(stats) + 6
+        ws.cell(row=summary_row, column=1, value="Итого:").font = Font(bold=True)
+        ws.cell(row=summary_row + 1, column=1, value=f"Всего студентов: {total_users}")
+        ws.cell(row=summary_row + 2, column=1, value=f"Прошли тест: {attempted_users}")
+        ws.cell(row=summary_row + 3, column=1, value=f"Сдали: {passed_users}")
+        if attempted_users > 0:
+            success_rate = round(passed_users / attempted_users * 100)
+            ws.cell(row=summary_row + 4, column=1, value=f"Процент сдачи: {success_rate}%")
+        if grades:
+            avg_grade = round(sum(grades) / len(grades), 1)
+            ws.cell(row=summary_row + 5, column=1, value=f"Средняя оценка: {avg_grade}")
+        
+        output = io.BytesIO()
+        wb.save(output)
+        output.seek(0)
+        return output.read()
+    
+    async def generate_group_report(self, test_id: int, group_number: int) -> ExcelReportResult:
+        test = await self._test_dao.get_by_id(test_id)
+        if not test:
+            return ExcelReportResult(success=False, caption="❌ Тест не найден")
+        
+        stats = await self._attempt_repo.get_group_test_statistics(test_id, group_number)
+        if not stats:
+            return ExcelReportResult(success=False, caption=f"❌ В группе {group_number} нет студентов")
+        
+        excel_bytes = self.create_test_report(test.title, group_number, stats)
+        safe_title = "".join(c if c.isalnum() or c in "-_" else "_" for c in test.title)[:30]
+        filename = f"{safe_title}_group_{group_number}.xlsx"
+        
+        return ExcelReportResult(
+            success=True,
+            data=excel_bytes,
+            filename=filename,
+            caption=f"📊 <b>Статистика по тесту</b>\n\n📝 {test.title}\n🎓 Группа {group_number}",
+        )
diff --git a/src/quizzi/service/test.py b/src/quizzi/service/test.py
new file mode 100644
index 0000000..8128f8a
--- /dev/null
+++ b/src/quizzi/service/test.py
@@ -0,0 +1,184 @@
+from dataclasses import dataclass
+from datetime import datetime
+
+from quizzi.domain.schemas import Test
+from quizzi.infrastructure.database.dao.test import TestDAO
+from quizzi.infrastructure.database.dao.user import UserDAO
+from quizzi.infrastructure.database.repo.test import TestRepository
+from quizzi.infrastructure.database.repo.test_attempt import TestAttemptRepository
+from quizzi.infrastructure.utils.config import Config
+from quizzi.infrastructure.utils.test_id_to_hash import decode_id, encode_id
+from quizzi.infrastructure.utils.timezone import now_msk_naive
+
+
+@dataclass
+class TestValidationResult:
+    is_valid: bool
+    error: str = ""
+    test: Test | None = None
+
+
+@dataclass
+class TestAccessResult:
+    can_access: bool
+    error: str = ""
+    remaining_attempts: int | None = None
+
+
+@dataclass
+class TestUpdateResult:
+    success: bool
+    message: str
+
+
+class TestService:
+    def __init__(
+        self,
+        test_dao: TestDAO,
+        test_repo: TestRepository,
+        attempt_repo: TestAttemptRepository,
+        user_dao: UserDAO,
+        config: Config,
+    ) -> None:
+        self._test_dao = test_dao
+        self._test_repo = test_repo
+        self._attempt_repo = attempt_repo
+        self._user_dao = user_dao
+        self._config = config
+    
+    def decode_test_hash(self, test_hash: str) -> int | None:
+        try:
+            return decode_id(test_hash, self._config.security.encode_key)
+        except (ValueError, IndexError):
+            return None
+    
+    def encode_test_id(self, test_id: int) -> str:
+        return encode_id(
+            test_id,
+            self._config.security.encode_key,
+            self._config.security.encoded_string_length,
+        )
+    
+    async def validate_test(self, test_id: int, user_id: int) -> TestValidationResult:
+        test = await self._test_dao.get_by_id(test_id)
+        
+        if not test:
+            return TestValidationResult(is_valid=False, error="❌ Тест не найден")
+        
+        if not test.is_active:
+            return TestValidationResult(is_valid=False, error="❌ Тест деактивирован", test=test)
+        
+        if test.expires_at and test.expires_at < now_msk_naive():
+            return TestValidationResult(is_valid=False, error="❌ Срок действия теста истек", test=test)
+        
+        user = await self._user_dao.get_by_id(user_id)
+        if test.for_group and user and user.group != test.for_group:
+            return TestValidationResult(
+                is_valid=False,
+                error=f"❌ Тест доступен только для группы {test.for_group}",
+                test=test,
+            )
+        
+        return TestValidationResult(is_valid=True, test=test)
+    
+    async def check_test_access(self, test_id: int, user_id: int) -> TestAccessResult:
+        test = await self._test_dao.get_by_id(test_id)
+        
+        if not test:
+            return TestAccessResult(can_access=False, error="❌ Тест не найден")
+        
+        if not test.is_active:
+            return TestAccessResult(can_access=False, error="❌ Тест деактивирован")
+        
+        if test.expires_at and test.expires_at < now_msk_naive():
+            return TestAccessResult(can_access=False, error="❌ Срок действия теста истек")
+        
+        if test.attempts:
+            attempts = await self._attempt_repo.get_user_test_attempts(user_id, test_id)
+            finished_attempts = [a for a in attempts if a.finished_at]
+            remaining = test.attempts - len(finished_attempts)
+            
+            if remaining <= 0:
+                return TestAccessResult(
+                    can_access=False,
+                    error="❌ Вы исчерпали все попытки",
+                    remaining_attempts=0,
+                )
+            
+            return TestAccessResult(can_access=True, remaining_attempts=remaining)
+        
+        return TestAccessResult(can_access=True)
+    
+    async def get_available_tests(self, user_id: int, user_group: int | None) -> list[Test]:
+        return await self._test_repo.get_available_tests_for_user(user_id, user_group)
+    
+    async def toggle_test_active(self, test_id: int) -> TestUpdateResult:
+        test = await self._test_dao.get_by_id(test_id)
+        if not test:
+            return TestUpdateResult(success=False, message="❌ Тест не найден")
+        
+        await self._test_dao.update(test_id, is_active=not test.is_active)
+        action = "деактивирован" if test.is_active else "активирован"
+        return TestUpdateResult(success=True, message=f"✅ Тест {action}")
+    
+    async def toggle_results_viewable(self, test_id: int) -> TestUpdateResult:
+        test = await self._test_dao.get_by_id(test_id)
+        if not test:
+            return TestUpdateResult(success=False, message="❌ Тест не найден")
+        
+        await self._test_dao.update(test_id, are_results_viewable=not test.are_results_viewable)
+        action = "скрыты" if test.are_results_viewable else "видны"
+        return TestUpdateResult(success=True, message=f"✅ Результаты теперь {action}")
+    
+    async def delete_test(self, test_id: int) -> bool:
+        return await self._test_dao.delete(test_id)
+    
+    async def update_password(self, test_id: int, password: str) -> TestUpdateResult:
+        if len(password) > 255:
+            return TestUpdateResult(success=False, message="❌ Пароль слишком длинный (максимум 255 символов)")
+        await self._test_dao.update(test_id, password=password)
+        return TestUpdateResult(success=True, message="✅ Пароль обновлен")
+    
+    async def remove_password(self, test_id: int) -> TestUpdateResult:
+        await self._test_dao.update(test_id, password=None)
+        return TestUpdateResult(success=True, message="✅ Пароль удален")
+    
+    async def update_attempts(self, test_id: int, attempts: int) -> TestUpdateResult:
+        if attempts < 1:
+            return TestUpdateResult(success=False, message="❌ Количество попыток должно быть больше 0")
+        if attempts > 100:
+            return TestUpdateResult(success=False, message="❌ Количество попыток не может быть больше 100")
+        await self._test_dao.update(test_id, attempts=attempts)
+        return TestUpdateResult(success=True, message="✅ Количество попыток обновлено")
+    
+    async def remove_attempts(self, test_id: int) -> TestUpdateResult:
+        await self._test_dao.update(test_id, attempts=None)
+        return TestUpdateResult(success=True, message="✅ Ограничение попыток удалено")
+    
+    async def update_time_limit(self, test_id: int, minutes: int) -> TestUpdateResult:
+        if minutes < 1:
+            return TestUpdateResult(success=False, message="❌ Лимит времени должен быть больше 0")
+        if minutes > 1440:
+            return TestUpdateResult(success=False, message="❌ Лимит времени не может быть больше 1440 минут (24 часа)")
+        await self._test_dao.update(test_id, time_limit=minutes * 60)
+        return TestUpdateResult(success=True, message="✅ Лимит времени обновлен")
+    
+    async def remove_time_limit(self, test_id: int) -> TestUpdateResult:
+        await self._test_dao.update(test_id, time_limit=None)
+        return TestUpdateResult(success=True, message="✅ Лимит времени удален")
+    
+    async def update_group(self, test_id: int, group: int) -> TestUpdateResult:
+        await self._test_dao.update(test_id, for_group=group)
+        return TestUpdateResult(success=True, message="✅ Группа обновлена")
+    
+    async def remove_group(self, test_id: int) -> TestUpdateResult:
+        await self._test_dao.update(test_id, for_group=None)
+        return TestUpdateResult(success=True, message="✅ Тест теперь доступен для всех групп")
+    
+    async def update_expires(self, test_id: int, expires_at: datetime) -> TestUpdateResult:
+        await self._test_dao.update(test_id, expires_at=expires_at)
+        return TestUpdateResult(success=True, message="✅ Срок действия обновлен")
+    
+    async def remove_expires(self, test_id: int) -> TestUpdateResult:
+        await self._test_dao.update(test_id, expires_at=None)
+        return TestUpdateResult(success=True, message="✅ Срок действия удален")
diff --git a/src/quizzi/service/test_attempt.py b/src/quizzi/service/test_attempt.py
new file mode 100644
index 0000000..fa689df
--- /dev/null
+++ b/src/quizzi/service/test_attempt.py
@@ -0,0 +1,204 @@
+from dataclasses import dataclass
+from datetime import datetime
+
+from quizzi.domain.schemas import QuestionType
+from quizzi.infrastructure.database.dao.test import TestDAO
+from quizzi.infrastructure.database.dao.user_answer import UserAnswerDAO
+from quizzi.infrastructure.database.repo.test import TestRepository
+from quizzi.infrastructure.database.repo.test_attempt import TestAttemptRepository
+from quizzi.infrastructure.utils.timezone import now_msk_naive
+
+
+@dataclass
+class AttemptStartResult:
+    success: bool
+    attempt_id: int | None = None
+    questions: list[int] | None = None
+    started_at: datetime | None = None
+    error: str = ""
+
+
+@dataclass
+class AnswerResult:
+    success: bool
+    is_correct: bool = False
+    error: str = ""
+
+
+@dataclass
+class TestResult:
+    score: int
+    correct_count: int
+    total_questions: int
+    is_passed: bool
+
+
+class TestAttemptService:
+    def __init__(
+        self,
+        test_dao: TestDAO,
+        test_repo: TestRepository,
+        attempt_repo: TestAttemptRepository,
+        answer_dao: UserAnswerDAO,
+    ) -> None:
+        self._test_dao = test_dao
+        self._test_repo = test_repo
+        self._attempt_repo = attempt_repo
+        self._answer_dao = answer_dao
+    
+    async def start_attempt(self, user_id: int, test_id: int) -> AttemptStartResult:
+        active_attempt = await self._attempt_repo.get_active_attempt(user_id, test_id)
+        if active_attempt:
+            await self._attempt_repo.attempt_dao.delete(active_attempt.id)
+        
+        _, questions = await self._test_repo.get_test_with_questions(test_id)
+        if not questions:
+            return AttemptStartResult(success=False, error="❌ В тесте нет вопросов")
+        
+        attempt = await self._attempt_repo.attempt_dao.create(user_id=user_id, test_id=test_id)
+        started_at = now_msk_naive()
+        
+        return AttemptStartResult(
+            success=True,
+            attempt_id=attempt.id,
+            questions=[q.id for q in questions],
+            started_at=started_at,
+        )
+    
+    async def cancel_attempt(self, attempt_id: int) -> bool:
+        return await self._attempt_repo.attempt_dao.delete(attempt_id)
+    
+    async def save_single_answer(
+        self,
+        attempt_id: int,
+        question_id: int,
+        selected_option_id: int,
+    ) -> AnswerResult:
+        question, options = await self._test_repo.get_question_with_options(question_id)
+        if not question:
+            return AnswerResult(success=False, error="❌ Вопрос не найден")
+        
+        correct_options = [opt for opt in options if opt.is_correct]
+        is_correct = any(opt.id == selected_option_id for opt in correct_options)
+        selected_text = next((opt.text for opt in options if opt.id == selected_option_id), "")
+        
+        await self._answer_dao.create(
+            attempt_id=attempt_id,
+            question_id=question_id,
+            selected_option_id=selected_option_id,
+            text_answer=selected_text,
+            is_correct=is_correct,
+        )
+        
+        return AnswerResult(success=True, is_correct=is_correct)
+    
+    async def save_multiple_answer(
+        self,
+        attempt_id: int,
+        question_id: int,
+        selected_option_ids: list[int],
+    ) -> AnswerResult:
+        question, options = await self._test_repo.get_question_with_options(question_id)
+        if not question:
+            return AnswerResult(success=False, error="❌ Вопрос не найден")
+        
+        selected_texts = sorted([opt.text for opt in options if opt.id in selected_option_ids])
+        correct_texts = sorted([opt.text for opt in options if opt.is_correct])
+        is_correct = selected_texts == correct_texts
+        
+        await self._answer_dao.create(
+            attempt_id=attempt_id,
+            question_id=question_id,
+            text_answer="|".join(selected_texts),
+            is_correct=is_correct,
+        )
+        
+        return AnswerResult(success=True, is_correct=is_correct)
+    
+    async def save_text_answer(
+        self,
+        attempt_id: int,
+        question_id: int,
+        text_answer: str,
+    ) -> AnswerResult:
+        question, options = await self._test_repo.get_question_with_options(question_id)
+        if not question:
+            return AnswerResult(success=False, error="❌ Вопрос не найден")
+        
+        correct_options = [opt for opt in options if opt.is_correct]
+        user_normalized = text_answer.lower().replace(" ", "")
+        is_correct = any(opt.text.lower().replace(" ", "") == user_normalized for opt in correct_options)
+        
+        await self._answer_dao.create(
+            attempt_id=attempt_id,
+            question_id=question_id,
+            text_answer=text_answer,
+            is_correct=is_correct,
+        )
+        
+        return AnswerResult(success=True, is_correct=is_correct)
+    
+    async def finish_attempt(self, attempt_id: int, total_questions: int) -> TestResult:
+        correct_count = await self._attempt_repo.calculate_attempt_score(attempt_id)
+        score = round((correct_count / total_questions * 100)) if total_questions > 0 else 0
+        is_passed = score >= 50
+        
+        await self._attempt_repo.finish_attempt(attempt_id, score, is_passed)
+        
+        return TestResult(
+            score=score,
+            correct_count=correct_count,
+            total_questions=total_questions,
+            is_passed=is_passed,
+        )
+    
+    async def finish_by_timeout(
+        self,
+        attempt_id: int,
+        questions: list[int],
+        user_answers: dict,
+    ) -> TestResult:
+        answered_question_ids = set()
+        answers = await self._attempt_repo.get_answers_for_attempt(attempt_id)
+        for answer in answers:
+            answered_question_ids.add(answer.question_id)
+        
+        for question_id in questions:
+            if question_id in answered_question_ids:
+                continue
+            
+            answer_data = user_answers.get(str(question_id))
+            
+            if answer_data:
+                question, options = await self._test_repo.get_question_with_options(question_id)
+                if not question:
+                    continue
+                
+                if answer_data["type"] == "single":
+                    await self.save_single_answer(attempt_id, question_id, answer_data["answer"])
+                elif answer_data["type"] == "multiple":
+                    await self.save_multiple_answer(attempt_id, question_id, answer_data["answer"])
+            else:
+                await self._answer_dao.create(
+                    attempt_id=attempt_id,
+                    question_id=question_id,
+                    text_answer=None,
+                    is_correct=False,
+                )
+        
+        return await self.finish_attempt(attempt_id, len(questions))
+    
+    async def get_question_state(self, question_type: str):
+        from quizzi.application.bot.user_dialogs.states import UserTestSG
+        
+        if question_type == QuestionType.SINGLE:
+            return UserTestSG.question_single
+        elif question_type == QuestionType.MULTIPLE:
+            return UserTestSG.question_multiple
+        else:
+            return UserTestSG.question_input
+    
+    async def get_next_question_state(self, question_id: int):
+        question, _ = await self._test_repo.get_question_with_options(question_id)
+        question_type = question.question_type if question else QuestionType.SINGLE
+        return await self.get_question_state(question_type)
diff --git a/src/quizzi/service/user.py b/src/quizzi/service/user.py
new file mode 100644
index 0000000..ec25f1a
--- /dev/null
+++ b/src/quizzi/service/user.py
@@ -0,0 +1,75 @@
+from dataclasses import dataclass
+
+from quizzi.domain.schemas import User
+from quizzi.infrastructure.database.dao.group import GroupDAO
+from quizzi.infrastructure.database.dao.user import UserDAO
+
+
+@dataclass
+class RegistrationResult:
+    is_registered: bool
+    needs_name: bool = False
+    needs_group: bool = False
+    has_groups: bool = False
+    user: User | None = None
+
+
+class UserService:
+    def __init__(self, user_dao: UserDAO, group_dao: GroupDAO) -> None:
+        self._user_dao = user_dao
+        self._group_dao = group_dao
+    
+    async def check_registration(self, user_id: int) -> RegistrationResult:
+        user = await self._user_dao.get_by_id(user_id)
+        groups = await self._group_dao.get_all()
+        has_groups = len(groups) > 0
+        
+        if user is None:
+            return RegistrationResult(
+                is_registered=False,
+                needs_name=True,
+                needs_group=has_groups,
+                has_groups=has_groups,
+            )
+        
+        needs_name = user.name is None
+        needs_group = has_groups and user.group is None
+        
+        return RegistrationResult(
+            is_registered=not needs_name and not needs_group,
+            needs_name=needs_name,
+            needs_group=needs_group,
+            has_groups=has_groups,
+            user=user,
+        )
+    
+    async def create_user(
+        self,
+        user_id: int,
+        first_name: str,
+        username: str | None = None,
+        last_name: str | None = None,
+    ) -> User:
+        return await self._user_dao.create(
+            user_id=user_id,
+            first_name=first_name,
+            username=username,
+            last_name=last_name,
+        )
+    
+    async def update_user_info(
+        self,
+        user_id: int,
+        first_name: str,
+        username: str | None = None,
+        last_name: str | None = None,
+    ) -> User | None:
+        return await self._user_dao.upsert(
+            user_id=user_id,
+            first_name=first_name,
+            username=username,
+            last_name=last_name,
+        )
+    
+    async def get_all_users(self) -> list[User]:
+        return await self._user_dao.get_all()