diff --git a/space2stats_api/cdk/app.py b/space2stats_api/cdk/app.py
index 2b9f419..fdf3e7d 100644
--- a/space2stats_api/cdk/app.py
+++ b/space2stats_api/cdk/app.py
@@ -2,7 +2,6 @@
 from aws_stack import Space2StatsStack
 from settings import DeploymentSettings
 
-
 settings = DeploymentSettings(_env_file="aws_deployment.env")
 
 env = Environment(
@@ -14,4 +13,4 @@
 
 Space2StatsStack(app, "Space2StatsStack", env=env)
 
-app.synth()
\ No newline at end of file
+app.synth()
diff --git a/space2stats_api/cdk/aws_stack.py b/space2stats_api/cdk/aws_stack.py
index 50d08c8..eaec78f 100644
--- a/space2stats_api/cdk/aws_stack.py
+++ b/space2stats_api/cdk/aws_stack.py
@@ -1,15 +1,13 @@
-from aws_cdk import (
-    Stack,
-    aws_apigatewayv2 as apigatewayv2,
-    aws_apigatewayv2_integrations as integrations,
-    aws_lambda as _lambda,
-    aws_certificatemanager as acm,
-    Duration
-)
+from aws_cdk import Duration, Stack
+from aws_cdk import aws_apigatewayv2 as apigatewayv2
+from aws_cdk import aws_apigatewayv2_integrations as integrations
+from aws_cdk import aws_certificatemanager as acm
+from aws_cdk import aws_lambda as _lambda
 from aws_cdk.aws_lambda_python_alpha import PythonFunction
 from constructs import Construct
 from settings import AppSettings, DeploymentSettings
 
+
 class Space2StatsStack(Stack):
     def __init__(self, scope: Construct, id: str, **kwargs) -> None:
         super().__init__(scope, id, **kwargs)
@@ -28,7 +26,10 @@ def __init__(self, scope: Construct, id: str, **kwargs) -> None:
             memory_size=1024
         )
 
-        certificate = acm.Certificate.from_certificate_arn(self, "Certificate", deployment_settings.CDK_CERTIFICATE_ARN)
+        certificate = acm.Certificate.from_certificate_arn(
+            self, "Certificate",
+            deployment_settings.CDK_CERTIFICATE_ARN
+        )
 
         domain_name = apigatewayv2.DomainName(
             self, "DomainName",
@@ -49,4 +50,4 @@ def __init__(self, scope: Construct, id: str, **kwargs) -> None:
             api=http_api,
             domain_name=domain_name,
             stage=http_api.default_stage
-        )
\ No newline at end of file
+        )
diff --git a/space2stats_api/cdk/settings.py b/space2stats_api/cdk/settings.py
index c8903e4..fd22267 100644
--- a/space2stats_api/cdk/settings.py
+++ b/space2stats_api/cdk/settings.py
@@ -13,4 +13,4 @@ class DeploymentSettings(BaseSettings):
     CDK_DEFAULT_ACCOUNT: str
     CDK_DEFAULT_REGION: str
     CDK_CERTIFICATE_ARN: str
-    CDK_DOMAIN_NAME: str
\ No newline at end of file
+    CDK_DOMAIN_NAME: str
diff --git a/space2stats_api/src/app/main.py b/space2stats_api/src/app/main.py
index 3e02954..70e659d 100644
--- a/space2stats_api/src/app/main.py
+++ b/space2stats_api/src/app/main.py
@@ -1,6 +1,6 @@
 from fastapi import FastAPI
-from mangum import Mangum
 from fastapi.middleware.cors import CORSMiddleware
+from mangum import Mangum
 
 from .routers import api
 
@@ -8,7 +8,7 @@
 
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=["*"], 
+    allow_origins=["*"],
     allow_credentials=True,
     allow_methods=["*"],
     allow_headers=["*"],
@@ -20,4 +20,4 @@
 def read_root():
     return {"message": "Welcome to Space2Stats!"}
 
-handler = Mangum(app)
\ No newline at end of file
+handler = Mangum(app)
diff --git a/space2stats_api/src/app/routers/api.py b/space2stats_api/src/app/routers/api.py
index 2a00dea..ba9069e 100644
--- a/space2stats_api/src/app/routers/api.py
+++ b/space2stats_api/src/app/routers/api.py
@@ -1,12 +1,11 @@
-from typing import List, Dict, Any, Literal, Optional, TypeAlias
-from fastapi import APIRouter
+from typing import Any, Dict, List, Literal, Optional, TypeAlias
 
-from pydantic import BaseModel
+from fastapi import APIRouter
 from geojson_pydantic import Feature, Polygon
+from pydantic import BaseModel
 
-from ..utils.h3_utils import generate_h3_ids, generate_h3_geometries
 from ..utils.db_utils import get_available_fields, get_summaries
-
+from ..utils.h3_utils import generate_h3_geometries, generate_h3_ids
 
 router = APIRouter()
 
@@ -57,4 +56,4 @@ def get_summary(request: SummaryRequest):
 
 @router.get("/fields", response_model=List[str])
 def fields():
-    return get_available_fields()
\ No newline at end of file
+    return get_available_fields()
diff --git a/space2stats_api/src/app/settings.py b/space2stats_api/src/app/settings.py
index e2fbc58..9c07e99 100644
--- a/space2stats_api/src/app/settings.py
+++ b/space2stats_api/src/app/settings.py
@@ -11,4 +11,6 @@ class Settings(BaseSettings):
 
     @property
     def DB_CONNECTION_STRING(self) -> str:
-        return f"host={self.DB_HOST} port={self.DB_PORT} dbname={self.DB_NAME} user={self.DB_USER} password={self.DB_PASSWORD}"
\ No newline at end of file
+        host_port = f"host={self.DB_HOST} port={self.DB_PORT}"
+        db_user = f"dbname={self.DB_NAME} user={self.DB_USER}"
+        return f"{host_port} {db_user} password={self.DB_PASSWORD}"
diff --git a/space2stats_api/src/app/utils/db_utils.py b/space2stats_api/src/app/utils/db_utils.py
index 651f5ac..cc091b2 100644
--- a/space2stats_api/src/app/utils/db_utils.py
+++ b/space2stats_api/src/app/utils/db_utils.py
@@ -1,5 +1,6 @@
 import psycopg as pg
 from psycopg_pool import ConnectionPool
+
 from ..settings import Settings
 
 settings = Settings()
@@ -56,4 +57,4 @@ def get_available_fields():
     except Exception as e:
         raise e
 
-    return columns
\ No newline at end of file
+    return columns
diff --git a/space2stats_api/src/app/utils/h3_utils.py b/space2stats_api/src/app/utils/h3_utils.py
index 44bf9da..9a84e64 100644
--- a/space2stats_api/src/app/utils/h3_utils.py
+++ b/space2stats_api/src/app/utils/h3_utils.py
@@ -1,7 +1,7 @@
-from typing import Dict, Any, List, Optional
+from typing import Any, Dict, List, Optional
 
 import h3
-from shapely.geometry import shape, Polygon, Point, mapping
+from shapely.geometry import Point, Polygon, mapping, shape
 
 
 def generate_h3_ids(
@@ -55,7 +55,8 @@ def generate_h3_geometries(
 
     Parameters:
         h3_ids (List[str]): A list of H3 hexagon IDs.
-        geometry_type (Optional[str]): The type of geometry to generate ('polygon' or 'point').
+        geometry_type (Optional[str]):
+            The type of geometry to generate ('polygon' or 'point').
 
     Returns:
         List[Dict[str, Any]]: A list of geometries in GeoJSON format.
diff --git a/space2stats_api/tests/test_api.py b/space2stats_api/tests/test_api.py
index a6a3d00..baf688c 100644
--- a/space2stats_api/tests/test_api.py
+++ b/space2stats_api/tests/test_api.py
@@ -1,7 +1,8 @@
-from fastapi.testclient import TestClient
-import pytest
 from unittest.mock import patch
 
+import pytest
+from fastapi.testclient import TestClient
+
 from src.app.main import app
 
 client = TestClient(app)
@@ -32,7 +33,10 @@ def test_read_root():
 
 @patch("src.app.routers.api.get_summaries")
 def test_get_summary(mock_get_summaries):
-    mock_get_summaries.return_value = [("hex_1", 100, 200)], ["hex_id", "sum_pop_2020", "sum_pop_f_10_2020"]
+    mock_get_summaries.return_value = (
+        [("hex_1", 100, 200)],
+        ["hex_id", "sum_pop_2020", "sum_pop_f_10_2020"]
+    )
 
     request_payload = {
         "aoi": aoi,
@@ -50,12 +54,16 @@ def test_get_summary(mock_get_summaries):
         assert "hex_id" in summary
         for field in request_payload["fields"]:
             assert field in summary
-        assert len(summary) == len(request_payload["fields"]) + 1  # +1 for the 'hex_id'
+        # +1 for the 'hex_id'
+        assert len(summary) == len(request_payload["fields"]) + 1
 
 
 @patch("src.app.routers.api.get_summaries")
 def test_get_summary_with_geometry_polygon(mock_get_summaries):
-    mock_get_summaries.return_value = [("hex_1", 100, 200)], ["hex_id", "sum_pop_2020", "sum_pop_f_10_2020"]
+    mock_get_summaries.return_value = (
+        [("hex_1", 100, 200)],
+        ["hex_id", "sum_pop_2020", "sum_pop_f_10_2020"]
+    )
 
     request_payload = {
         "aoi": aoi,
@@ -76,12 +84,16 @@ def test_get_summary_with_geometry_polygon(mock_get_summaries):
         assert summary["geometry"]["type"] == "Polygon"
         for field in request_payload["fields"]:
             assert field in summary
-        assert len(summary) == len(request_payload["fields"]) + 2  # +1 for the 'hex_id' and +1 for 'geometry'
+        # +1 for the 'hex_id' and +1 for 'geometry'
+        assert len(summary) == len(request_payload["fields"]) + 2
 
 
 @patch("src.app.routers.api.get_summaries")
 def test_get_summary_with_geometry_point(mock_get_summaries):
-    mock_get_summaries.return_value = [("hex_1", 100, 200)], ["hex_id", "sum_pop_2020", "sum_pop_f_10_2020"]
+    mock_get_summaries.return_value = (
+        [("hex_1", 100, 200)],
+        ["hex_id", "sum_pop_2020", "sum_pop_f_10_2020"]
+    )
 
     request_payload = {
         "aoi": aoi,
@@ -102,22 +114,25 @@ def test_get_summary_with_geometry_point(mock_get_summaries):
         assert summary["geometry"]["type"] == "Point"
         for field in request_payload["fields"]:
             assert field in summary
-        assert len(summary) == len(request_payload["fields"]) + 2  # +1 for the 'hex_id' and +1 for 'geometry'
+        # +1 for the 'hex_id' and +1 for 'geometry'
+        assert len(summary) == len(request_payload["fields"]) + 2
 
 
 @patch("src.app.routers.api.get_available_fields")
 def test_get_fields(mock_get_available_fields):
-    mock_get_available_fields.return_value = ["sum_pop_2020", "sum_pop_f_10_2020", "field3"]
+    mock_get_available_fields.return_value = ["sum_pop_2020",
+                                              "sum_pop_f_10_2020",
+                                              "field3"]
 
     response = client.get("/fields")
 
     assert response.status_code == 200
     response_json = response.json()
-    
+
     expected_fields = ["sum_pop_2020", "sum_pop_f_10_2020", "field3"]
     for field in expected_fields:
         assert field in response_json
 
 
 if __name__ == "__main__":
-    pytest.main()
\ No newline at end of file
+    pytest.main()
diff --git a/space2stats_api/tests/test_db_utils.py b/space2stats_api/tests/test_db_utils.py
index 171f1cd..222f035 100644
--- a/space2stats_api/tests/test_db_utils.py
+++ b/space2stats_api/tests/test_db_utils.py
@@ -1,6 +1,7 @@
 import pytest
 from shapely.geometry import Polygon, mapping
-from src.app.utils.h3_utils import generate_h3_ids, generate_h3_geometries
+
+from src.app.utils.h3_utils import generate_h3_geometries, generate_h3_ids
 
 polygon_coords = [
     [-74.3, 40.5],
@@ -64,4 +65,4 @@ def test_generate_h3_geometries_invalid_type():
 
 
 if __name__ == "__main__":
-    pytest.main()
\ No newline at end of file
+    pytest.main()
diff --git a/space2stats_api/tests/test_h3_utils.py b/space2stats_api/tests/test_h3_utils.py
index 7813dda..222f035 100644
--- a/space2stats_api/tests/test_h3_utils.py
+++ b/space2stats_api/tests/test_h3_utils.py
@@ -1,6 +1,7 @@
 import pytest
 from shapely.geometry import Polygon, mapping
-from src.app.utils.h3_utils import generate_h3_ids, generate_h3_geometries
+
+from src.app.utils.h3_utils import generate_h3_geometries, generate_h3_ids
 
 polygon_coords = [
     [-74.3, 40.5],