diff --git a/pyproject.toml b/pyproject.toml
index cf14991..299a837 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,3 +21,8 @@ openec2 = "openec2:main"
 [build-system]
 requires = ["hatchling"]
 build-backend = "hatchling.build"
+
+[dependency-groups]
+dev = [
+    "ruff>=0.11.2",
+]
diff --git a/src/openec2/actions/deregister_image.py b/src/openec2/actions/deregister_image.py
index 8bebcf7..7d6c724 100644
--- a/src/openec2/actions/deregister_image.py
+++ b/src/openec2/actions/deregister_image.py
@@ -7,6 +7,7 @@ from openec2.db import DatabaseDep
 from openec2.db.image import AMI
 from openec2.images import garbage_collect_image
 
+
 def deregister_image(
     params: QueryParams,
     config: OpenEC2Config,
diff --git a/src/openec2/actions/describe_images.py b/src/openec2/actions/describe_images.py
index b17645d..ac367fa 100644
--- a/src/openec2/actions/describe_images.py
+++ b/src/openec2/actions/describe_images.py
@@ -30,7 +30,7 @@ def describe_images(
             requestId=uuid.uuid4().hex,
             imagesSet=ImagesSet(
                 items=images,
-            )
+            ),
         ).to_xml(),
         media_type="application/xml",
     )
diff --git a/src/openec2/actions/describe_instances.py b/src/openec2/actions/describe_instances.py
index be2bf4f..fc3148f 100644
--- a/src/openec2/actions/describe_instances.py
+++ b/src/openec2/actions/describe_instances.py
@@ -5,12 +5,20 @@ from fastapi.datastructures import QueryParams
 from sqlmodel import select
 
 from openec2.libvirt import LibvirtSingleton
-from openec2.api.describe_instances import InstanceDescription, DescribeInstancesResponse, DescribeInstancesResponseReservationSet, ReservationSet, ReservationSetInstancesSet, describe_instance
+from openec2.api.describe_instances import (
+    InstanceDescription,
+    DescribeInstancesResponse,
+    DescribeInstancesResponseReservationSet,
+    ReservationSet,
+    ReservationSetInstancesSet,
+    describe_instance,
+)
 from openec2.api.shared import InstanceState
 from openec2.config import OpenEC2Config
 from openec2.db import DatabaseDep
 from openec2.db.instance import Instance
 
+
 def describe_instances(
     params: QueryParams,
     config: OpenEC2Config,
@@ -36,7 +44,8 @@ def describe_instances(
                         instancesSet=ReservationSetInstancesSet(
                             item=[instance],
                         ),
-                    ) for instance in response_items
+                    )
+                    for instance in response_items
                 ],
             ),
         ).to_xml(),
diff --git a/src/openec2/actions/import_image.py b/src/openec2/actions/import_image.py
index 14de2f6..d8c9c9f 100644
--- a/src/openec2/actions/import_image.py
+++ b/src/openec2/actions/import_image.py
@@ -11,6 +11,7 @@ from openec2.config import OpenEC2Config
 from openec2.db import DatabaseDep
 from openec2.db.image import AMI
 
+
 def import_image(
     params: QueryParams,
     config: OpenEC2Config,
diff --git a/src/openec2/actions/run_instances.py b/src/openec2/actions/run_instances.py
index 6838a5f..d492e8d 100644
--- a/src/openec2/actions/run_instances.py
+++ b/src/openec2/actions/run_instances.py
@@ -15,9 +15,14 @@ from openec2.db.image import AMI
 from openec2.api.run_instances import RunInstanceResponse, RunInstanceInstanceSet
 from openec2.api.describe_instances import describe_instance
 from openec2.utils.array import parse_array_objects
-from openec2.ipam import get_available_ipv4, is_ipv4_available, add_instance_dhcp_mapping
+from openec2.ipam import (
+    get_available_ipv4,
+    is_ipv4_available,
+    add_instance_dhcp_mapping,
+)
 from openec2.utils.ip import generate_available_mac
 
+
 def create_libvirt_domain(
     name: str,
     memory: int,
@@ -84,6 +89,7 @@ def create_libvirt_domain(
 </domain>
 """
 
+
 def run_instances(
     params: QueryParams,
     config: OpenEC2Config,
@@ -94,7 +100,7 @@ def run_instances(
 
     instance_type = config.instances.types.get(params["InstanceType"])
     if instance_type is None:
-        raise Exception(f"Unknown instance type {params["InstanceType"]}")
+        raise Exception(f"Unknown instance type {params['InstanceType']}")
 
     ami = db.exec(select(AMI).where(AMI.id == image_id)).first()
     if ami is None:
@@ -140,7 +146,9 @@ def run_instances(
         id=instance_id,
         imageId=image_id,
         tags=tags,
-        userData=base64.b64decode(value).decode() if (value := params.get("UserData")) is not None else None,
+        userData=base64.b64decode(value).decode()
+        if (value := params.get("UserData")) is not None
+        else None,
         privateIPv4=private_ipv4,
         interfaceMac=mac,
     )
diff --git a/src/openec2/actions/terminate_instances.py b/src/openec2/actions/terminate_instances.py
index 042e179..faa4100 100644
--- a/src/openec2/actions/terminate_instances.py
+++ b/src/openec2/actions/terminate_instances.py
@@ -18,6 +18,7 @@ from openec2.api.terminate_instances import TerminateInstancesResponse, Instance
 
 logger = logging.getLogger()
 
+
 def terminate_instances(
     params: QueryParams,
     config: OpenEC2Config,
@@ -31,7 +32,7 @@ def terminate_instances(
         instance = db.exec(select(Instance).where(Instance.id == instance_id)).first()
         if instance is None:
             continue
-            #raise HTTPException(status_code=404, detail="Unknown instance")
+            # raise HTTPException(status_code=404, detail="Unknown instance")
 
         dom = conn.lookupByName(instance_id)
         prev_state = describe_instance_state(dom)
@@ -54,7 +55,9 @@ def terminate_instances(
         instance_disk.unlink()
 
         image_ids.add(instance.imageId)
-        remove_instance_dhcp_mapping(instance.id, instance.interfaceMac, instance.privateIPv4, db)
+        remove_instance_dhcp_mapping(
+            instance.id, instance.interfaceMac, instance.privateIPv4, db
+        )
         db.delete(instance)
 
     db.commit()
diff --git a/src/openec2/api/describe_images.py b/src/openec2/api/describe_images.py
index c17bf57..950ad0f 100644
--- a/src/openec2/api/describe_images.py
+++ b/src/openec2/api/describe_images.py
@@ -1,5 +1,6 @@
 from pydantic_xml import BaseXmlModel, element
 
+
 class Image(BaseXmlModel):
     imageId: str = element()
 
@@ -7,13 +8,15 @@ class Image(BaseXmlModel):
 
     name: str = element()
 
+
 class ImagesSet(BaseXmlModel, tag="imagesSet"):
     items: list[Image] = element(tag="item")
 
+
 class DescribeImagesResponse(
     BaseXmlModel,
     tag="DescribeImagesResponse",
-    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"}
+    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"},
 ):
     requestId: str = element()
 
diff --git a/src/openec2/api/describe_instances.py b/src/openec2/api/describe_instances.py
index e8738e8..3633664 100644
--- a/src/openec2/api/describe_instances.py
+++ b/src/openec2/api/describe_instances.py
@@ -9,9 +9,11 @@ class InstanceTag(BaseXmlModel):
     key: str = element()
     value: str = element()
 
+
 class InstanceTagSet(BaseXmlModel):
     item: list[InstanceTag] = element()
 
+
 class InstanceDescription(
     BaseXmlModel,
     tag="item",
@@ -25,20 +27,23 @@ class InstanceDescription(
 class ReservationSetInstancesSet(BaseXmlModel):
     item: list[InstanceDescription] = element()
 
+
 class ReservationSet(BaseXmlModel):
     reservationId: str = element()
     instancesSet: ReservationSetInstancesSet = element()
 
+
 class DescribeInstancesResponseReservationSet(
     BaseXmlModel,
     tag="reservationSet",
 ):
     item: list[ReservationSet] = element("")
 
+
 class DescribeInstancesResponse(
     BaseXmlModel,
     tag="DescribeInstancesResponse",
-    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"}
+    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"},
 ):
     request_id: str = element(tag="requestId")
     reservation_set: DescribeInstancesResponseReservationSet = element("reservationSet")
@@ -51,7 +56,10 @@ def describe_instance_state(domain: libvirt.virDomain) -> InstanceState:
         name="running" if running else "stopped",
     )
 
-def describe_instance(instance: Instance, domain: libvirt.virDomain) -> InstanceDescription:
+
+def describe_instance(
+    instance: Instance, domain: libvirt.virDomain
+) -> InstanceDescription:
     return InstanceDescription(
         instance_id=instance.id,
         image_id=instance.imageId,
@@ -61,7 +69,8 @@ def describe_instance(instance: Instance, domain: libvirt.virDomain) -> Instance
                 InstanceTag(
                     key=key,
                     value=value,
-                ) for key, value in instance.tags.items()
+                )
+                for key, value in instance.tags.items()
             ],
         ),
     )
diff --git a/src/openec2/api/run_instances.py b/src/openec2/api/run_instances.py
index 1eed661..5e37066 100644
--- a/src/openec2/api/run_instances.py
+++ b/src/openec2/api/run_instances.py
@@ -1,12 +1,12 @@
 from pydantic_xml import BaseXmlModel, element
 
-from openec2.db.instance import Instance
-from openec2.api.shared import InstanceState
 from openec2.api.describe_instances import InstanceDescription
 
+
 class RunInstanceInstanceSet(BaseXmlModel):
     item: list[InstanceDescription] = element()
 
+
 class RunInstanceResponse(BaseXmlModel):
     request_id: str = element(tag="requestId")
 
diff --git a/src/openec2/api/start_instances.py b/src/openec2/api/start_instances.py
index b199548..90a0550 100644
--- a/src/openec2/api/start_instances.py
+++ b/src/openec2/api/start_instances.py
@@ -6,7 +6,7 @@ from openec2.api.shared import InstancesSet
 class StartInstancesResponse(
     BaseXmlModel,
     tag="StartInstancesResponse",
-    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"}
+    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"},
 ):
     request_id: str = element(tag="requestId")
     instancesSet: InstancesSet = element()
diff --git a/src/openec2/api/stop_instances.py b/src/openec2/api/stop_instances.py
index 932b150..ac34443 100644
--- a/src/openec2/api/stop_instances.py
+++ b/src/openec2/api/stop_instances.py
@@ -6,7 +6,7 @@ from openec2.api.shared import InstancesSet
 class StopInstancesResponse(
     BaseXmlModel,
     tag="StopInstancesResponse",
-    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"}
+    nsmap={"": "http://ec2.amazonaws.com/doc/2016-11-15/"},
 ):
     requestId: str = element(tag="requestId")
     instancesSet: InstancesSet = element()
diff --git a/src/openec2/cli/add_user.py b/src/openec2/cli/add_user.py
index 2b680c6..3e8bd0f 100644
--- a/src/openec2/cli/add_user.py
+++ b/src/openec2/cli/add_user.py
@@ -41,5 +41,6 @@ def main():
     print(f"Access key: {access_key}")
     print(f"Secret access key: {secret_access_key}")
 
+
 if __name__ == "__main__":
     main()
diff --git a/src/openec2/config.py b/src/openec2/config.py
index 9ef80b6..a04ff12 100644
--- a/src/openec2/config.py
+++ b/src/openec2/config.py
@@ -3,19 +3,23 @@ from fastapi import Depends
 from pydantic import BaseModel
 from typing import Annotated
 
+
 class _OpenEC2InstanceType(BaseModel):
-    memory: int # MiB
+    memory: int  # MiB
     vcpu: float
-    disk: int # Gi
+    disk: int  # Gi
+
 
 class _OpenEC2InstanceConfig(BaseModel):
     location: Path
 
     types: dict[str, _OpenEC2InstanceType]
 
+
 class _OpenEC2LibvirtConfig(BaseModel):
     connection: str
 
+
 class _OpenEC2DatabaseConfig(BaseModel):
     # DB URL for sqlmodel
     url: str
@@ -23,6 +27,7 @@ class _OpenEC2DatabaseConfig(BaseModel):
     # Print SQL statements
     debug: bool
 
+
 class _OpenEC2Config(BaseModel):
     images: Path
     seed: Path
@@ -32,6 +37,7 @@ class _OpenEC2Config(BaseModel):
     debug: bool
     insecure: bool
 
+
 def _get_config() -> _OpenEC2Config:
     # TODO: Read from disk
     return _OpenEC2Config(
@@ -47,9 +53,7 @@ def _get_config() -> _OpenEC2Config:
                 ),
             },
         ),
-        libvirt=_OpenEC2LibvirtConfig(
-            connection="qemu:///system"
-        ),
+        libvirt=_OpenEC2LibvirtConfig(connection="qemu:///system"),
         debug=True,
         insecure=False,
         database=_OpenEC2DatabaseConfig(
@@ -58,6 +62,7 @@ def _get_config() -> _OpenEC2Config:
         ),
     )
 
+
 class ConfigSingleton:
     __instance: "ConfigSingleton | None" = None
 
@@ -75,4 +80,5 @@ class ConfigSingleton:
             ConfigSingleton.__instance = ConfigSingleton()
         return ConfigSingleton.__instance
 
+
 OpenEC2Config = Annotated[_OpenEC2Config, Depends(ConfigSingleton.of().get_config)]
diff --git a/src/openec2/db/__init__.py b/src/openec2/db/__init__.py
index 7c2137a..27ac23c 100644
--- a/src/openec2/db/__init__.py
+++ b/src/openec2/db/__init__.py
@@ -12,8 +12,10 @@ engine = create_engine(
     echo=ConfigSingleton.of().config.database.debug,
 )
 
+
 def get_session() -> Generator[Session]:
     with Session(engine) as session:
         yield session
 
+
 DatabaseDep = Annotated[Session, Depends(get_session)]
diff --git a/src/openec2/db/image.py b/src/openec2/db/image.py
index 60be1fc..e433aa3 100644
--- a/src/openec2/db/image.py
+++ b/src/openec2/db/image.py
@@ -1,5 +1,6 @@
 from sqlmodel import SQLModel, Field
 
+
 class AMI(SQLModel, table=True):
     # ID of the AMI
     id: str = Field(default=None, primary_key=True)
diff --git a/src/openec2/db/instance.py b/src/openec2/db/instance.py
index a6428e6..b0a0e33 100644
--- a/src/openec2/db/instance.py
+++ b/src/openec2/db/instance.py
@@ -1,5 +1,6 @@
 from sqlmodel import SQLModel, Field, JSON, Column
 
+
 class Instance(SQLModel, table=True):
     id: str = Field(default=None, primary_key=True)
 
diff --git a/src/openec2/db/ipam.py b/src/openec2/db/ipam.py
index b528291..0392d36 100644
--- a/src/openec2/db/ipam.py
+++ b/src/openec2/db/ipam.py
@@ -19,6 +19,4 @@ class IPAMEntry(SQLModel, table=True):
     def set_ipv4(self, addr: str):
         self.ipv4_addr_raw = ipv4_to_int(addr)
 
-    __table_args = (
-        PrimaryKeyConstraint("ipv4_addr_raw", "vpc_id"),
-    )
+    __table_args = (PrimaryKeyConstraint("ipv4_addr_raw", "vpc_id"),)
diff --git a/src/openec2/db/user.py b/src/openec2/db/user.py
index 7efe4b1..843684e 100644
--- a/src/openec2/db/user.py
+++ b/src/openec2/db/user.py
@@ -1,5 +1,6 @@
 from sqlmodel import SQLModel, Field
 
+
 class User(SQLModel, table=True):
     id: int = Field(default=None, primary_key=True)
 
diff --git a/src/openec2/db/vpc.py b/src/openec2/db/vpc.py
index 2253c9e..478f60b 100644
--- a/src/openec2/db/vpc.py
+++ b/src/openec2/db/vpc.py
@@ -1,5 +1,6 @@
 from sqlmodel import SQLModel, Field, PrimaryKeyConstraint
 
+
 class VPC(SQLModel, table=True):
     # ID of the VPC
     id: str = Field(default=None, primary_key=True)
diff --git a/src/openec2/images.py b/src/openec2/images.py
index 6c804ee..8d221d4 100644
--- a/src/openec2/images.py
+++ b/src/openec2/images.py
@@ -13,7 +13,9 @@ def garbage_collect_image(image_id: str, db: DatabaseDep):
         print(instances)
         return
 
-    ami = db.exec(select(AMI).where(AMI.id == image_id, AMI.deregistered == True)).first()
+    ami = db.exec(
+        select(AMI).where(AMI.id == image_id, AMI.deregistered == True)
+    ).first()
     if ami is not None:
         db.delete(ami)
         db.commit()
diff --git a/src/openec2/ipam.py b/src/openec2/ipam.py
index 8cb6539..1a3d5d5 100644
--- a/src/openec2/ipam.py
+++ b/src/openec2/ipam.py
@@ -34,9 +34,16 @@ def add_instance_dhcp_mapping(instance_id: str, mac: str, ipv4: str, db: Databas
         flags=libvirt.VIR_NETWORK_UPDATE_AFFECT_LIVE,
     )
 
-def remove_instance_dhcp_mapping(instance_id: str, mac: str ,ipv4: str, db: DatabaseDep):
+
+def remove_instance_dhcp_mapping(
+    instance_id: str, mac: str, ipv4: str, db: DatabaseDep
+):
     i = ipv4_to_int(ipv4)
-    entry = db.exec(select(IPAMEntry).where(IPAMEntry.ipv4_addr_raw == i, IPAMEntry.instance_id == instance_id)).first()
+    entry = db.exec(
+        select(IPAMEntry).where(
+            IPAMEntry.ipv4_addr_raw == i, IPAMEntry.instance_id == instance_id
+        )
+    ).first()
     db.delete(entry)
 
     # Tell libvirt about this mapping
@@ -49,13 +56,21 @@ def remove_instance_dhcp_mapping(instance_id: str, mac: str ,ipv4: str, db: Data
         flags=libvirt.VIR_NETWORK_UPDATE_AFFECT_LIVE,
     )
 
+
 def is_ipv4_available(ipv4: str, db: DatabaseDep) -> bool:
     i = ipv4_to_int(ipv4)
-    return db.exec(select(IPAMEntry).where(IPAMEntry.ipv4_addr_raw == i)).first() is None
+    return (
+        db.exec(select(IPAMEntry).where(IPAMEntry.ipv4_addr_raw == i)).first() is None
+    )
+
 
 def get_available_ipv4(db: DatabaseDep) -> str:
     entries = db.exec(select(IPAMEntry)).all()
     # TODO: Use the VPC's subnet
-    max_ip = max(e.ipv4_addr_raw for e in entries) if entries else ipv4_to_int("192.168.122.2")
+    max_ip = (
+        max(e.ipv4_addr_raw for e in entries)
+        if entries
+        else ipv4_to_int("192.168.122.2")
+    )
     # TODO: Check if we're still inside the subnet
     return int_to_ipv4(max_ip + 1)
diff --git a/src/openec2/main.py b/src/openec2/main.py
index e57fb90..ddf7841 100644
--- a/src/openec2/main.py
+++ b/src/openec2/main.py
@@ -21,27 +21,35 @@ from openec2.db.instance import Instance
 
 app = FastAPI()
 
+
 @app.on_event("startup")
 def on_startup():
     SQLModel.metadata.create_all(engine)
 
+
 @app.get("/healthz", response_model=None)
 def healthz():
     return {
         "status": "OK",
     }
 
+
 @app.get("/Action", response_model=None)
 def action(request: Request, config: OpenEC2Config, db: DatabaseDep, _: AWSSignature):
     return run_action(request, config, db, cast(dict, request.query_params))
 
+
 @app.post("/Action", response_model=None)
-async def test(request: Request, config: OpenEC2Config, db: DatabaseDep, _: AWSSignature):
+async def test(
+    request: Request, config: OpenEC2Config, db: DatabaseDep, _: AWSSignature
+):
     query_params = {
-        key: value[0] for key, value in parse_qs((await request.body()).decode()).items()
+        key: value[0]
+        for key, value in parse_qs((await request.body()).decode()).items()
     }
     return run_action(request, config, db, cast(dict, query_params))
 
+
 def run_action(
     request: Request,
     config: OpenEC2Config,
@@ -68,7 +76,9 @@ def cloud_init_data(instance_id: str, entry: str, db: DatabaseDep):
         raise HTTPException(status_code=404, detail="Unknown cloud-init file")
 
     if entry == "user-data":
-        instance = db.exec(select(Instance).where(Instance.id == instance_id)).first()[0]
+        instance = db.exec(select(Instance).where(Instance.id == instance_id)).first()[
+            0
+        ]
         if instance is None:
             raise HTTPException(status_code=404, detail="Unknown instance")
 
@@ -79,17 +89,21 @@ def cloud_init_data(instance_id: str, entry: str, db: DatabaseDep):
             media_type="application/yaml",
         )
     elif entry == "meta-data":
-        return multiline_yaml_response([
-            f"instance-id: {instance_id}",
-            f"local-hostname: {instance_id}",
-        ])
+        return multiline_yaml_response(
+            [
+                f"instance-id: {instance_id}",
+                f"local-hostname: {instance_id}",
+            ]
+        )
     elif entry == "vendor-data":
-        return multiline_yaml_response([
-            "#cloud-config",
-            "growpart:",
-            "   devices: [/]",
-            "   ignore_growroot_disabled: true",
-        ])
+        return multiline_yaml_response(
+            [
+                "#cloud-config",
+                "growpart:",
+                "   devices: [/]",
+                "   ignore_growroot_disabled: true",
+            ]
+        )
     elif entry == "network-config":
         return Response(
             "",
diff --git a/src/openec2/security/aws.py b/src/openec2/security/aws.py
index eac55de..6012c4a 100644
--- a/src/openec2/security/aws.py
+++ b/src/openec2/security/aws.py
@@ -19,6 +19,7 @@ def _hmac_sha256(key: bytes, payload: bytes) -> bytes:
     h.update(payload)
     return h.finalize()
 
+
 @dataclass
 class AWSRequest:
     # The entire used URL
@@ -36,43 +37,57 @@ class AWSRequest:
     # The payload, if we used a POST/PUT
     payload: str | None
 
-    def sign(self, secret_access_key: str, region: str, product: str, credential_scope: str) -> str:
+    def sign(
+        self, secret_access_key: str, region: str, product: str, credential_scope: str
+    ) -> str:
         dt = datetime.datetime.fromisoformat(self.headers["X-Amz-Date"])
 
         canonical_query_string_keys = sorted(self.params.keys())
-        canonical_query_string = "&".join([
-            f"{key}={quote(self.params[key][0])}" for key in canonical_query_string_keys if key not in (
-                "X-Amz-Signature",
+        canonical_query_string = "&".join(
+            [
+                f"{key}={quote(self.params[key][0])}"
+                for key in canonical_query_string_keys
+                if key not in ("X-Amz-Signature",)
+            ]
+        )
+        canonical_header_string_keys = sorted(
+            [name for name in self.headers.keys() if include_in_canonical_string(name)]
+        )
+        canonical_header_string = (
+            "\n".join(
+                [
+                    f"{name.lower()}:{self.headers[name].strip()}"
+                    for name in canonical_header_string_keys
+                ]
             )
-        ])
-        canonical_header_string_keys = sorted([
-            name for name in self.headers.keys() if include_in_canonical_string(name)
-        ])
-        canonical_header_string = "\n".join([
-            f"{name.lower()}:{self.headers[name].strip()}" for name in canonical_header_string_keys
-        ]) + "\n"
+            + "\n"
+        )
         signed_headers = ";".join(canonical_header_string_keys)
         hashed_payload = sha256((self.payload or "").encode()).hexdigest()
-        canonical_request = "\n".join([
-            self.method.upper(),
-            self.url.path or "/",
-            #canonical_query_string,
-            "",
-            canonical_header_string,
-            signed_headers,
-            hashed_payload,
-        ])
+        canonical_request = "\n".join(
+            [
+                self.method.upper(),
+                self.url.path or "/",
+                # canonical_query_string,
+                "",
+                canonical_header_string,
+                signed_headers,
+                hashed_payload,
+            ]
+        )
         print("Canonical request")
         print(canonical_request)
 
         hashed_canonical_request = sha256(canonical_request.encode()).hexdigest()
         date = dt.strftime("%Y%m%d")
-        string_to_sign = "\n".join([
-            "AWS4-HMAC-SHA256",
-            dt.strftime("%Y%m%dT%H%M%SZ"),
-            credential_scope,
-            hashed_canonical_request,
-        ])
+        string_to_sign = "\n".join(
+            [
+                "AWS4-HMAC-SHA256",
+                dt.strftime("%Y%m%dT%H%M%SZ"),
+                credential_scope,
+                hashed_canonical_request,
+            ]
+        )
 
         print("String to sign")
         print(string_to_sign)
@@ -83,6 +98,7 @@ class AWSRequest:
         signing_key = _hmac_sha256(date_region_service_key, "aws4_request".encode())
         return _hmac_sha256(signing_key, string_to_sign.encode()).hex()
 
+
 @dataclass
 class AWSAuthentication:
     x_amz_algorithm: str
@@ -91,10 +107,12 @@ class AWSAuthentication:
 
     x_amz_signature: str
 
+
 def include_in_canonical_string(name: str) -> bool:
     lower = name.lower()
     return lower in ("host", "content-type") or lower.startswith("x-amz")
 
+
 def get_authentication_info(request: Request) -> AWSAuthentication:
     if request.method == "POST":
         algorithm, rest = request.headers["Authorization"].split(" ", 1)
@@ -110,21 +128,30 @@ def get_authentication_info(request: Request) -> AWSAuthentication:
         )
 
     return AWSAuthentication(
-        "", "", "",
+        "",
+        "",
+        "",
     )
 
+
 async def check_request_signature(request: Request, db: DatabaseDep):
     # Do not check if we don't care
     if ConfigSingleton.of().config.insecure:
         return
 
     body = (await request.body()).decode()
-    query_params = cast(dict, parse_qs(body)) if request.method == "POST" else cast(dict, request.query_params)
+    query_params = (
+        cast(dict, parse_qs(body))
+        if request.method == "POST"
+        else cast(dict, request.query_params)
+    )
 
     auth_info = get_authentication_info(request)
 
     if auth_info.x_amz_algorithm != "AWS4-HMAC-SHA256":
-        raise HTTPException(status_code=400, detail=f"Invalid signature algorithm: {x_amz_algorithm}")
+        raise HTTPException(
+            status_code=400, detail=f"Invalid signature algorithm: {x_amz_algorithm}"
+        )
 
     x_amz_credential = auth_info.x_amz_credential
 
@@ -145,13 +172,12 @@ async def check_request_signature(request: Request, db: DatabaseDep):
         user.secret_access_key,
         region,
         service,
-        "/".join([
-            date, region, service, key
-        ]),
+        "/".join([date, region, service, key]),
     )
 
     print(x_amz_signature, signature)
     if x_amz_signature != signature:
         raise HTTPException(status_code=401)
 
+
 AWSSignature = Annotated[None, Depends(check_request_signature)]
diff --git a/src/openec2/utils/array.py b/src/openec2/utils/array.py
index 75f7d61..60ab58a 100644
--- a/src/openec2/utils/array.py
+++ b/src/openec2/utils/array.py
@@ -10,6 +10,7 @@ def parse_array_objects(prefix: str, params: dict) -> list[dict[str, str]]:
         items[parts[1]][".".join(parts[2:])] = value
     return list(items.values())
 
+
 def parse_array_plain(prefix: str, params: dict[str, str]) -> list[str]:
     items: dict[str, str] = {}
     for key, value in params.items():
diff --git a/src/openec2/utils/ip.py b/src/openec2/utils/ip.py
index d12f0b3..4851821 100644
--- a/src/openec2/utils/ip.py
+++ b/src/openec2/utils/ip.py
@@ -9,17 +9,19 @@ from openec2.db.instance import Instance
 def ipv4_to_int(ip: str) -> int:
     i = 0
     for idx, p in enumerate(ip.split(".")):
-        i += (int(p) << (3-idx)*8)
+        i += int(p) << (3 - idx) * 8
     return i
 
+
 def int_to_ipv4(ip: int) -> str:
     parts: list[int] = []
     for i in reversed(range(4)):
         parts.append(
-            (ip >> i*8) & 255,
+            (ip >> i * 8) & 255,
         )
     return ".".join(str(p) for p in parts)
 
+
 def generate_mac() -> str:
     mac_bytes = random.randbytes(6)
     mac = ""
@@ -35,10 +37,14 @@ def generate_mac() -> str:
             mac += f"{h}:"
     return mac[:-1]
 
+
 def generate_available_mac(db: DatabaseDep) -> str:
     mac = ""
     while True:
         mac = generate_mac()
-        if db.exec(select(Instance).where(Instance.interfaceMac == mac)).first() is None:
+        if (
+            db.exec(select(Instance).where(Instance.interfaceMac == mac)).first()
+            is None
+        ):
             break
     return mac
diff --git a/src/openec2/utils/qemu.py b/src/openec2/utils/qemu.py
index 542a0e6..b7722eb 100644
--- a/src/openec2/utils/qemu.py
+++ b/src/openec2/utils/qemu.py
@@ -3,12 +3,17 @@ import subprocess
 
 
 def create_cow_copy(src: Path, dst: Path, size: str):
-    subprocess.call([
-        "qemu-img",
-        "create",
-        "-f", "qcow2",
-        "-b", str(src),
-        "-F", "qcow2",
-        str(dst),
-        size,
-    ])
+    subprocess.call(
+        [
+            "qemu-img",
+            "create",
+            "-f",
+            "qcow2",
+            "-b",
+            str(src),
+            "-F",
+            "qcow2",
+            str(dst),
+            size,
+        ]
+    )
diff --git a/src/openec2/utils/text.py b/src/openec2/utils/text.py
index 6fa4f4d..6956e79 100644
--- a/src/openec2/utils/text.py
+++ b/src/openec2/utils/text.py
@@ -1,5 +1,6 @@
 from fastapi import Response
 
+
 def multiline_yaml_response(lines: list[str]) -> Response:
     return Response(
         "\n".join(lines),
diff --git a/tests/openec2/utils/test_array.py b/tests/openec2/utils/test_array.py
index 631db3e..b62b43e 100644
--- a/tests/openec2/utils/test_array.py
+++ b/tests/openec2/utils/test_array.py
@@ -14,6 +14,7 @@ def test_array_parsing_keys():
     assert parsed[1]["a"] == "3"
     assert parsed[1]["b"] == "4"
 
+
 def test_array_plain_parsing():
     params = {
         "Key.1": "1",
diff --git a/uv.lock b/uv.lock
index f4206e0..daed187 100644
--- a/uv.lock
+++ b/uv.lock
@@ -373,6 +373,11 @@ dependencies = [
     { name = "sqlmodel" },
 ]
 
+[package.dev-dependencies]
+dev = [
+    { name = "ruff" },
+]
+
 [package.metadata]
 requires-dist = [
     { name = "cryptography", specifier = ">=44.0.2" },
@@ -384,6 +389,9 @@ requires-dist = [
     { name = "sqlmodel", specifier = ">=0.0.24" },
 ]
 
+[package.metadata.requires-dev]
+dev = [{ name = "ruff", specifier = ">=0.11.2" }]
+
 [[package]]
 name = "packaging"
 version = "24.2"
@@ -568,6 +576,31 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/70/a2/dc0ae0b61d5fce9eec3763c98d5a471f7b07c891a2cbfb3fd6a0f632a9a1/rich_toolkit-0.14.0-py3-none-any.whl", hash = "sha256:75ff4b3e70e27e9cb145164bfe8d8e56758162fa3f87594067f4d85630b98bf9", size = 24062 },
 ]
 
+[[package]]
+name = "ruff"
+version = "0.11.2"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/90/61/fb87430f040e4e577e784e325351186976516faef17d6fcd921fe28edfd7/ruff-0.11.2.tar.gz", hash = "sha256:ec47591497d5a1050175bdf4e1a4e6272cddff7da88a2ad595e1e326041d8d94", size = 3857511 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/62/99/102578506f0f5fa29fd7e0df0a273864f79af044757aef73d1cae0afe6ad/ruff-0.11.2-py3-none-linux_armv6l.whl", hash = "sha256:c69e20ea49e973f3afec2c06376eb56045709f0212615c1adb0eda35e8a4e477", size = 10113146 },
+    { url = "https://files.pythonhosted.org/packages/74/ad/5cd4ba58ab602a579997a8494b96f10f316e874d7c435bcc1a92e6da1b12/ruff-0.11.2-py3-none-macosx_10_12_x86_64.whl", hash = "sha256:2c5424cc1c4eb1d8ecabe6d4f1b70470b4f24a0c0171356290b1953ad8f0e272", size = 10867092 },
+    { url = "https://files.pythonhosted.org/packages/fc/3e/d3f13619e1d152c7b600a38c1a035e833e794c6625c9a6cea6f63dbf3af4/ruff-0.11.2-py3-none-macosx_11_0_arm64.whl", hash = "sha256:ecf20854cc73f42171eedb66f006a43d0a21bfb98a2523a809931cda569552d9", size = 10224082 },
+    { url = "https://files.pythonhosted.org/packages/90/06/f77b3d790d24a93f38e3806216f263974909888fd1e826717c3ec956bbcd/ruff-0.11.2-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:0c543bf65d5d27240321604cee0633a70c6c25c9a2f2492efa9f6d4b8e4199bb", size = 10394818 },
+    { url = "https://files.pythonhosted.org/packages/99/7f/78aa431d3ddebfc2418cd95b786642557ba8b3cb578c075239da9ce97ff9/ruff-0.11.2-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl", hash = "sha256:20967168cc21195db5830b9224be0e964cc9c8ecf3b5a9e3ce19876e8d3a96e3", size = 9952251 },
+    { url = "https://files.pythonhosted.org/packages/30/3e/f11186d1ddfaca438c3bbff73c6a2fdb5b60e6450cc466129c694b0ab7a2/ruff-0.11.2-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:955a9ce63483999d9f0b8f0b4a3ad669e53484232853054cc8b9d51ab4c5de74", size = 11563566 },
+    { url = "https://files.pythonhosted.org/packages/22/6c/6ca91befbc0a6539ee133d9a9ce60b1a354db12c3c5d11cfdbf77140f851/ruff-0.11.2-py3-none-manylinux_2_17_ppc64.manylinux2014_ppc64.whl", hash = "sha256:86b3a27c38b8fce73bcd262b0de32e9a6801b76d52cdb3ae4c914515f0cef608", size = 12208721 },
+    { url = "https://files.pythonhosted.org/packages/19/b0/24516a3b850d55b17c03fc399b681c6a549d06ce665915721dc5d6458a5c/ruff-0.11.2-py3-none-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl", hash = "sha256:a3b66a03b248c9fcd9d64d445bafdf1589326bee6fc5c8e92d7562e58883e30f", size = 11662274 },
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+    { url = "https://files.pythonhosted.org/packages/86/54/3c12d3af58012a5e2cd7ebdbe9983f4834af3f8cbea0e8a8c74fa1e23b2b/ruff-0.11.2-py3-none-win_amd64.whl", hash = "sha256:3170150172a8f994136c0c66f494edf199a0bbea7a409f649e4bc8f4d7084080", size = 11373713 },
+    { url = "https://files.pythonhosted.org/packages/d6/d4/dd813703af8a1e2ac33bf3feb27e8a5ad514c9f219df80c64d69807e7f71/ruff-0.11.2-py3-none-win_arm64.whl", hash = "sha256:52933095158ff328f4c77af3d74f0379e34fd52f175144cefc1b192e7ccd32b4", size = 10441990 },
+]
+
 [[package]]
 name = "shellingham"
 version = "1.5.4"