diff --git a/solution/assets/images/backend-coverage.png b/solution/assets/images/backend-coverage.png
new file mode 100644
index 0000000..71bfd39
Binary files /dev/null and b/solution/assets/images/backend-coverage.png differ
diff --git a/solution/infrastructure/.gitignore b/solution/infrastructure/.gitignore
index 7d35adf..dad66cc 100644
--- a/solution/infrastructure/.gitignore
+++ b/solution/infrastructure/.gitignore
@@ -1,4 +1,4 @@
-# Custom evnironment files
+# Custom environment files
 .env
 
 # Password files
diff --git a/solution/infrastructure/backend/.env.template b/solution/infrastructure/backend/.env.template
index e219fb4..2fac0be 100644
--- a/solution/infrastructure/backend/.env.template
+++ b/solution/infrastructure/backend/.env.template
@@ -8,15 +8,16 @@ DJANGO_LANGUAGE_CODE=en-us
 DJANGO_STATIC_URL=http://localhost:13241/
 REDIS_URI=redis://redis:6379
 DJANGO_DB_URI=postgresql://postgres:postgres@postgres/postgres
+
 DJANGO_CREATE_SUPERUSER=True
 DJANGO_SUPERUSER_USERNAME=admin
 DJANGO_SUPERUSER_EMAIL=admin@mail.com
 DJANGO_SUPERUSER_PASSWORD=admin
+
 YANDEX_CLOUD_FOLDER_ID=b1grd7nb04jbfvgm9121
 YANDEX_CLOUD_API_KEY=AQVN19lztDgUcBrHeW0HtJ0bbDGda6i6e3InXsDl
+
 MINIO_ENDPOINT=minio:9000
 MINIO_CUSTOM_ENDPOINT_URL=http://127.0.0.1:13244
 MINIO_ACCESS_KEY=admin
 MINIO_SECRET_KEY=password
-DJANGO_NOTIFIER_TELEGRAM_BOT_TOKEN=6196898691:AAFucgj7ieEuYMvWG_MZAn0Ao3UBuHpvaVY
-DJANGO_NOTIFIER_TELEGRAM_CHAT_ID=-1002304409222
diff --git a/solution/services/backend/.env.template b/solution/services/backend/.env.template
index 378245d..5988a69 100644
--- a/solution/services/backend/.env.template
+++ b/solution/services/backend/.env.template
@@ -31,12 +31,3 @@ DJANGO_CREATE_SUPERUSER=False
 DJANGO_SUPERUSER_USERNAME=
 DJANGO_SUPERUSER_EMAIL=
 DJANGO_SUPERUSER_PASSWORD=
-
-
-# Notifiers settings (only with DJANGO_DEBUG=False)
-
-# Telegram
-
-DJANGO_NOTIFIER_TELEGRAM_BOT_TOKEN=
-DJANGO_NOTIFIER_TELEGRAM_CHAT_ID=
-DJANGO_NOTIFIER_TELEGRAM_THREAD_ID=
diff --git a/solution/services/backend/Dockerfile.staticfiles b/solution/services/backend/Dockerfile.staticfiles
index fb3fef2..5150bf5 100644
--- a/solution/services/backend/Dockerfile.staticfiles
+++ b/solution/services/backend/Dockerfile.staticfiles
@@ -19,7 +19,7 @@ COPY . .
 
 RUN uv run python manage.py collectstatic --noinput
 
-# Stage 2: Start nginx to serve staticfiles
+# Stage 2: Start nginx and serve staticfiles
 FROM docker.io/nginx:latest
 
 COPY --from=builder /app/static /usr/share/nginx/html
diff --git a/solution/services/backend/api/v1/clients/tests.py b/solution/services/backend/api/v1/clients/tests.py
index 03a323f..a61f8ad 100644
--- a/solution/services/backend/api/v1/clients/tests.py
+++ b/solution/services/backend/api/v1/clients/tests.py
@@ -1,6 +1,5 @@
 from http import HTTPStatus as status
 from django.test import TestCase
-from django.urls import reverse
 import json
 from uuid import uuid4
 from apps.client.models import Client
diff --git a/solution/services/backend/apps/advertiser/tests/test_advertiser_model.py b/solution/services/backend/apps/advertiser/tests/test_advertiser_model.py
index 08b5806..c0e5e91 100644
--- a/solution/services/backend/apps/advertiser/tests/test_advertiser_model.py
+++ b/solution/services/backend/apps/advertiser/tests/test_advertiser_model.py
@@ -22,6 +22,7 @@ class AdvertiserModelTest(TestCase):
 
         new_id = uuid4()
         self.advertiser.advertiser_id = new_id
+
         self.assertEqual(self.advertiser.id, new_id)
 
     @override_settings(
diff --git a/solution/services/backend/apps/campaign/models.py b/solution/services/backend/apps/campaign/models.py
index a60d5b8..c8ba5a8 100644
--- a/solution/services/backend/apps/campaign/models.py
+++ b/solution/services/backend/apps/campaign/models.py
@@ -6,7 +6,6 @@ from uuid import UUID
 
 from django.conf import settings
 from django.core.cache import cache
-from django.core.exceptions import ValidationError
 from django.core.validators import (
     MaxValueValidator,
     MinLengthValidator,
@@ -20,6 +19,7 @@ from apps.campaign.validators import (
     CampaignDurationValidator,
     CampaignLimitsValidator,
     CampaignReportMessageValidator,
+    CampaignStartDateValidator,
     CampaignTargetingLocationValidator,
 )
 from apps.client.models import Client
@@ -100,21 +100,7 @@ class Campaign(BaseModel):
         CampaignAgeValidator()(self)
         CampaignDurationValidator()(self)
         CampaignLimitsValidator()(self)
-
-        current_date = cache.get("current_date", default=0)
-
-        err = "start_date must be greater than the current date."
-
-        try:
-            original = Campaign.objects.get(id=self.id or "")
-            if (
-                original.start_date != self.start_date
-                and self.start_date < current_date
-            ):
-                raise ValidationError(err)
-        except Campaign.DoesNotExist:
-            if self.start_date < current_date:
-                raise ValidationError(err) from None
+        CampaignStartDateValidator()(self)
 
     def save(self, *args: Any, **kwargs: Any) -> None:
         created = self.pk is None
@@ -134,6 +120,20 @@ class Campaign(BaseModel):
         )
         cache.set(f"campaign_{self.id}_clicks_count", self.clicks.count())
 
+    def inc_views(self) -> None:
+        try:
+            cache.incr(f"campaign_{self.id}_impressions_count", 1)
+        except ValueError:
+            self.setup_cache()
+            logger.warning("Seems that %s missing caches", self.campaign_id)
+
+    def inc_clicks(self) -> None:
+        try:
+            cache.incr(f"campaign_{self.id}_clicks_count", 1)
+        except ValueError:
+            self.setup_cache()
+            logger.warning("Seems that %s missing caches", self.campaign_id)
+
     @property
     def ad_id(self) -> UUID:
         return self.id
@@ -175,13 +175,7 @@ class Campaign(BaseModel):
                 price=self.cost_per_impression,
                 date=cache.get("current_date", default=0),
             )
-            try:
-                cache.incr(f"campaign_{self.id}_impressions_count", 1)
-            except ValueError:
-                self.setup_cache()
-                logger.warning(
-                    "Seems that %s missing caches", self.campaign_id
-                )
+            self.inc_views()
         except ConflictError:
             pass
 
@@ -198,13 +192,7 @@ class Campaign(BaseModel):
                 price=self.cost_per_click,
                 date=cache.get("current_date", default=0),
             )
-            try:
-                cache.incr(f"campaign_{self.id}_clicks_count", 1)
-            except ValueError:
-                self.setup_cache()
-                logger.warning(
-                    "Seems that %s missing caches", self.campaign_id
-                )
+            self.inc_clicks()
         except ConflictError:
             pass
 
@@ -235,7 +223,6 @@ class Campaign(BaseModel):
             total=models.Count("id"),
             spent=models.Sum("price", default=0.0),
         )
-
         clicks = self.clicks.values("date").annotate(
             total=models.Count("id"),
             spent=models.Sum("price", default=0.0),
diff --git a/solution/services/backend/apps/campaign/validators.py b/solution/services/backend/apps/campaign/validators.py
index 98426a9..ff45719 100644
--- a/solution/services/backend/apps/campaign/validators.py
+++ b/solution/services/backend/apps/campaign/validators.py
@@ -1,48 +1,83 @@
+from typing import TYPE_CHECKING
+
+from django.core.cache import cache
 from django.core.exceptions import ValidationError
+from django.db.models.fields import Field
+
+if TYPE_CHECKING:
+    from apps.campaign.models import Campaign, CampaignReport
+
+
+class CampaignTargetingLocationValidator:
+    def __call__(self, instance: "Campaign") -> None:
+        if instance.location == "":
+            err = {
+                "targeting": {
+                    type(
+                        instance
+                    ).location.field.name: Field.default_error_messages[
+                        "blank"
+                    ]
+                }
+            }
+            raise ValidationError(err)
 
 
 class CampaignAgeValidator:
-    def __call__(self, instance) -> None:  # noqa: ANN001
+    def __call__(self, instance: "Campaign") -> None:
         if (
             isinstance(instance.age_from, int)
             and isinstance(instance.age_to, int)
             and instance.age_from > instance.age_to
         ):
-            err = "age_from can't be greater than age_to"
+            err = "targeting.age_from can't be greater than targeting.age_to."
             raise ValidationError(err)
 
 
 class CampaignDurationValidator:
-    def __call__(self, instance) -> None:  # noqa: ANN001
+    def __call__(self, instance: "Campaign") -> None:
         if (
             isinstance(instance.start_date, int)
             and isinstance(instance.end_date, int)
             and instance.start_date > instance.end_date
         ):
-            err = "start_date can't be greater than end_date"
+            err = "start_date can't be greater than end_date."
             raise ValidationError(err)
 
 
 class CampaignLimitsValidator:
-    def __call__(self, instance) -> None:  # noqa: ANN001
+    def __call__(self, instance: "Campaign") -> None:
         if (
             isinstance(instance.impressions_limit, int)
             and isinstance(instance.clicks_limit, int)
             and instance.impressions_limit < instance.clicks_limit
         ):
-            err = "clicks_limit can't be greater than impressions_limit"
+            err = "clicks_limit can't be greater than impressions_limit."
             raise ValidationError(err)
 
 
-class CampaignTargetingLocationValidator:
-    def __call__(self, instance) -> None:  # noqa: ANN001
-        if instance.location == "":
-            err = "targeting.location cannot be blank"
-            raise ValidationError(err)
+class CampaignStartDateValidator:
+    def __call__(self, instance: "Campaign") -> None:
+        current_date = cache.get("current_date", default=0)
+        err = "start_date must be greater or equal than the current_date."
+        try:
+            original = type(instance).objects.get(id=instance.id or "")
+            if (
+                original.start_date != instance.start_date
+                and instance.start_date < current_date
+            ):
+                raise ValidationError(err)
+        except type(instance).DoesNotExist:
+            if instance.start_date < current_date:
+                raise ValidationError(err) from None
 
 
 class CampaignReportMessageValidator:
-    def __call__(self, instance) -> None:  # noqa: ANN001
+    def __call__(self, instance: "CampaignReport") -> None:
         if instance.message == "":
-            err = "message cannot be blank"
+            err = {
+                instance.message.field.name: Field.default_error_messages[
+                    "blank"
+                ]
+            }
             raise ValidationError(err)
diff --git a/solution/services/backend/config/notifiers/__init__.py b/solution/services/backend/config/notifiers/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/solution/services/backend/config/notifiers/telegram.py b/solution/services/backend/config/notifiers/telegram.py
deleted file mode 100644
index 6ca3a65..0000000
--- a/solution/services/backend/config/notifiers/telegram.py
+++ /dev/null
@@ -1,133 +0,0 @@
-import datetime
-import logging
-import time
-import traceback
-from concurrent.futures import ThreadPoolExecutor
-
-import httpx
-from django.utils.timezone import get_current_timezone
-
-TELEGRAM_LOG_HANDLER = logging.getLogger("telegram_log_handler")
-
-LEVEL_EMOJIS = {
-    "DEBUG": "🐞",
-    "INFO": "ℹ️",
-    "WARNING": "⚠️",
-    "ERROR": "❌",
-    "CRITICAL": "🚨",
-}
-
-
-class LoggingHandler(logging.Handler):
-    _executor = ThreadPoolExecutor(max_workers=5)
-
-    def __init__(
-        self,
-        token: str,
-        chat_id: int,
-        thread_id: int | None = None,
-        retries: int | None = 3,
-        delay: int | None = 2,
-        timeout: int | None = 5,
-    ) -> None:
-        super().__init__()
-
-        self.token = token
-        self.chat_id = chat_id
-        self.thread_id = thread_id
-        self.retries = retries
-        self.delay = delay
-        self.timeout = timeout
-        self.api_url = f"https://api.telegram.org/bot{self.token}/sendMessage"
-
-        self.template = (
-            "<b>{levelname}</b>\n"
-            "\t<b>Guid:</b> <code>{correlation_id}</code>\n"
-            "\t<b>Timestamp:</b> <code>{asctime}</code>\n"
-            "\t<b>Logger:</b> <code>{name}</code>\n"
-            "\t<b>File:</b> <code>{pathname}</code> "
-            "(Line: <code>{lineno}</code>)\n\n"
-            '<pre><code class="language-message">{message}</code></pre>\n'
-        )
-
-    def emit(self, record: logging.LogRecord) -> None:
-        try:
-            formatted_record = self.format(record)
-            self._executor.submit(self._send_message, formatted_record)
-        except Exception as e:  # noqa: BLE001
-            self.handleError(record)
-            TELEGRAM_LOG_HANDLER.exception(e)
-
-    def _send_message(self, formatted_record: str) -> None:
-        payload = {
-            "chat_id": self.chat_id,
-            "text": formatted_record,
-            "parse_mode": "HTML",
-        }
-        if self.thread_id:
-            payload["reply_to_message_id"] = self.thread_id
-
-        for attempt in range(1, self.retries + 1):
-            response = httpx.post(
-                self.api_url,
-                data=payload,
-                timeout=self.timeout,
-            )
-            if response.status_code != httpx.codes.OK:
-                if attempt == self.retries:
-                    TELEGRAM_LOG_HANDLER.exception(
-                        "Failed to send to Telegram after %d attempts: %s",
-                        self.retries,
-                        response.text,
-                    )
-                else:
-                    time.sleep(self.delay)
-            else:
-                return
-
-    def format(self, record: logging.LogRecord) -> str:
-        try:
-            asctime = datetime.datetime.fromtimestamp(
-                record.created,
-                tz=get_current_timezone(),
-            ).strftime("%Y-%m-%d %H:%M:%S %Z")
-            level_emoji = LEVEL_EMOJIS.get(record.levelname, "")
-
-            formatted_message = self.template.format(
-                levelname=f"{level_emoji} {record.levelname}",
-                correlation_id=getattr(record, "correlation_id", "N/A"),
-                asctime=asctime,
-                name=record.name,
-                pathname=record.pathname,
-                lineno=record.lineno,
-                message=record.getMessage(),
-            )
-
-            if record.exc_info:
-                formatted_message += self._format_exception(record.exc_info)
-
-            formatted_message += (
-                f"\n#{record.levelname.lower()} "
-                f"#{record.name.replace('.', '_')}"
-            )
-            if hasattr(record, "correlation_id"):
-                formatted_message += f" #{record.correlation_id}"
-        except Exception as format_error:  # noqa: BLE001
-            TELEGRAM_LOG_HANDLER.exception(
-                "Error formatting log record: %s",
-                format_error,
-            )
-            return f"Error formatting log record: {format_error}"
-        else:
-            return formatted_message
-
-    @staticmethod
-    def _format_exception(exc_info: Exception) -> str:
-        exc_text = "".join(traceback.format_exception(*exc_info))
-        return (
-            f"\n<pre><code class='language-traceback'>{exc_text}</code></pre>"
-        )
-
-    @classmethod
-    def shutdown_executor(cls) -> None:
-        cls._executor.shutdown(wait=True)
diff --git a/solution/services/backend/config/settings.py b/solution/services/backend/config/settings.py
index 122b846..a1d1102 100644
--- a/solution/services/backend/config/settings.py
+++ b/solution/services/backend/config/settings.py
@@ -41,7 +41,8 @@ YANDEX_CLOUD_INTEGRATION_ENABLED = (
     YANDEX_CLOUD_FOLDER_ID and YANDEX_CLOUD_API_KEY
 )
 
-# Register healthcheck
+
+# Register healthchecks
 
 plugin_dir.register(YandexAIHealthCheck)
 
@@ -300,26 +301,6 @@ USE_X_FORWARDED_PORT = False
 WSGI_APPLICATION = "config.wsgi.application"
 
 
-# Notifiers
-
-# Telegram
-
-NOTIFIER_TELEGRAM_BOT_TOKEN = env(
-    "DJANGO_NOTIFIER_TELEGRAM_BOT_TOKEN",
-    default=None,
-)
-
-NOTIFIER_TELEGRAM_CHAT_ID = env(
-    "DJANGO_NOTIFIER_TELEGRAM_CHAT_ID",
-    default=None,
-)
-
-NOTIFIER_TELEGRAM_THREAD_ID = env(
-    "DJANGO_NOTIFIER_TELEGRAM_THREAD_ID",
-    default=None,
-)
-
-
 # Logging
 
 LOGGER_NAME = "adnova"
@@ -435,24 +416,6 @@ LOGGING = {
 LOGGING_CONFIG = "logging.config.dictConfig"
 
 
-if NOTIFIER_TELEGRAM_BOT_TOKEN and NOTIFIER_TELEGRAM_CHAT_ID:
-    LOGGING_HANDLERS["telegram"] = {
-        "class": "config.notifiers.telegram.LoggingHandler",
-        "level": "INFO",
-        "filters": ["require_debug_false"],
-        "token": NOTIFIER_TELEGRAM_BOT_TOKEN,
-        "chat_id": NOTIFIER_TELEGRAM_CHAT_ID,
-        "thread_id": NOTIFIER_TELEGRAM_THREAD_ID,
-        "retries": 5,
-        "delay": 2,
-        "timeout": 5,
-    }
-    LOGGING_LOGGERS["django"]["handlers"].append("telegram")
-    LOGGING_LOGGERS["django.request"]["handlers"].append("telegram")
-    LOGGING_LOGGERS["health-check"]["handlers"].append("telegram")
-    LOGGING_LOGGERS[LOGGER_NAME]["handlers"].append("telegram")
-
-
 # Models
 
 ABSOLUTE_URL_OVERRIDES: dict[str, Callable] = {}
diff --git a/solution/services/backend/integrations/yandexai/healthcheck.py b/solution/services/backend/integrations/yandexai/healthcheck.py
index 3f4659b..48fe99a 100644
--- a/solution/services/backend/integrations/yandexai/healthcheck.py
+++ b/solution/services/backend/integrations/yandexai/healthcheck.py
@@ -16,8 +16,10 @@ class YandexAIHealthCheck(BaseHealthCheckBackend):
             result = sdk.models.completions(
                 "yandexgpt-lite", model_version="latest"
             ).tokenize("ping")
+
             if not result:
                 self.add_error("YandexAI API is unaccessible")
+
         except YCloudMLError:
             self.add_error("YandexAI API is unaccessible")
 
diff --git a/solution/tests/README.md b/solution/tests/README.md
index d338986..04d8c23 100644
--- a/solution/tests/README.md
+++ b/solution/tests/README.md
@@ -1,6 +1,6 @@
 # AdNova Tests
 
-There is `unit` tests and `e2e` tests available, unit tests are placed all around `backend` serivce folder and `e2e` tests placed [here](./e2e/)
+There is `unit` and `e2e` tests available, unit tests are placed all around `backend` serivce folder and `e2e` tests placed [here](./e2e/)
 
 ## Running unit tests
 
@@ -12,7 +12,7 @@ See [services/backend/README.md](../services/backend/README.md#testing)
 
 ### Backend service
 
--image-
+![backend coverage](../assets/images/backend-coverage.png)
 
 ## Running e2e tests
 
diff --git a/solution/tests/e2e/README.md b/solution/tests/e2e/README.md
index dd4bbf5..6ed5ed4 100644
--- a/solution/tests/e2e/README.md
+++ b/solution/tests/e2e/README.md
@@ -31,7 +31,7 @@ cd devitq/solution/tests/e2e
 uv sync --no-dev
 ```
 
-## Customize environment
+## Customize environment (optional)
 
 ```bash
 cp .env.template .env
diff --git a/solution/tests/e2e/pyproject.toml b/solution/tests/e2e/pyproject.toml
index cdaf1a1..2e81273 100644
--- a/solution/tests/e2e/pyproject.toml
+++ b/solution/tests/e2e/pyproject.toml
@@ -107,4 +107,3 @@ unfixable = []
 
 [tool.ruff.lint.pylint]
 max-args = 6
-
diff --git a/solution/tests/e2e/tests/test_ad_text_generation.py b/solution/tests/e2e/tests/test_ad_text_generation.py
index dcd499a..98e836b 100644
--- a/solution/tests/e2e/tests/test_ad_text_generation.py
+++ b/solution/tests/e2e/tests/test_ad_text_generation.py
@@ -8,8 +8,15 @@ logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
 
-# Tests integration between: backend, redis, yandexgpt and celery
 def test_generate_ad_text(client: Client) -> None:
+    """
+    Tests integration between:
+    - backend
+    - redis
+    - yandexgpt
+    - celery
+    """
+
     payload = {
         "advertiser_name": "Центральный Университет",
         "ad_title": "Всероссийский кейс-чемпионат DEADLINE",
@@ -25,10 +32,7 @@ def test_generate_ad_text(client: Client) -> None:
 
     while True:
         result_response = client.get(f"/generate/ad_text/{task_id}/result")
-        assert (
-            result_response.status_code == status.OK
-            or result_response.status_code == status.NOT_FOUND
-        )
+        assert result_response.status_code in (status.OK, status.NOT_FOUND)
         result_data = result_response.json()
 
         if (
diff --git a/solution/tests/e2e/tests/test_backend_health.py b/solution/tests/e2e/tests/test_backend_health.py
index b00804e..7a9a33e 100644
--- a/solution/tests/e2e/tests/test_backend_health.py
+++ b/solution/tests/e2e/tests/test_backend_health.py
@@ -9,7 +9,7 @@ logger = logging.getLogger(__name__)
 
 def test_healthcheck(client: Client) -> None:
     """
-    Checks that backend can use theese services:
+    Tests integration between:
     - redis
     - celery
     - postgres