diff --git a/.github/workflows/lint.yaml b/.github/workflows/lint.yaml
new file mode 100644
index 0000000..7b54188
--- /dev/null
+++ b/.github/workflows/lint.yaml
@@ -0,0 +1,20 @@
+name: linter
+on:
+  pull_request:
+    branches:
+      - main
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff
+      - name: Run Ruff
+        run: ruff check --output-format=github .
diff --git a/app/core/settings.py b/app/core/settings.py
index ea97d8d..341614f 100644
--- a/app/core/settings.py
+++ b/app/core/settings.py
@@ -4,16 +4,16 @@
 from dotenv import load_dotenv
 
 BASE_DIR = Path(__file__).resolve().parent.parent.parent
-dotenv_path = os.path.join(BASE_DIR, ".env")
+dotenv_path = os.path.join(BASE_DIR, '.env')
 
 
-if os.path.exists(dotenv_path):
+if Path(dotenv_path).exists():
     load_dotenv(dotenv_path)
 
 env = os.environ
 
-TELEGRAM_BOT_TOKEN = env.get("TELEGRAM_BOT_TOKEN")
+TELEGRAM_BOT_TOKEN = env.get('TELEGRAM_BOT_TOKEN')
 
-REDIS_HOST = env.get("REDIS_HOST")
-REDIS_PORT = env.get("REDIS_PORT")
-REDIS_URL = f"redis://{REDIS_HOST}:{REDIS_PORT}/0"
+REDIS_HOST = env.get('REDIS_HOST')
+REDIS_PORT = env.get('REDIS_PORT')
+REDIS_URL = f'redis://{REDIS_HOST}:{REDIS_PORT}/0'
diff --git a/app/main.py b/app/main.py
index ac14ce4..1b98307 100644
--- a/app/main.py
+++ b/app/main.py
@@ -10,10 +10,10 @@
 logger = logging.getLogger(__name__)
 
 
-async def main():
+async def main() -> None:
     logging.basicConfig(
         level=logging.INFO,
-        format='%(filename)s:%(lineno)d #%(levelname)-8s ' '[%(asctime)s] - %(name)s - %(message)s',
+        format='%(filename)s:%(lineno)d #%(levelname)-8s [%(asctime)s] - %(name)s - %(message)s',
     )
 
     logger.info('Starting bot')