diff --git a/src/infuse_iot/diff.py b/src/infuse_iot/diff.py
index e8082f0..815c9ad 100644
--- a/src/infuse_iot/diff.py
+++ b/src/infuse_iot/diff.py
@@ -6,7 +6,7 @@
 import binascii
 
 from collections import defaultdict
-from typing import List, Dict, Tuple
+from typing import List, Dict
 
 
 class ValidationError(Exception):
@@ -267,7 +267,6 @@ def __str__(self):
 class WriteInstr(Instr):
     class WriteU4(ctypes.LittleEndianStructure):
         op = OpCode.WRITE_LEN_U4
-        length = 1
         _fields_ = [
             ("opcode", ctypes.c_uint8),
         ]
diff --git a/src/infuse_iot/epacket.py b/src/infuse_iot/epacket.py
index a4abef7..0f06643 100644
--- a/src/infuse_iot/epacket.py
+++ b/src/infuse_iot/epacket.py
@@ -6,7 +6,7 @@
 import time
 import random
 
-from typing import List, Dict, Tuple, Any
+from typing import List, Dict, Tuple
 from typing_extensions import Self
 
 from infuse_iot.util.crypto import chachapoly_decrypt, chachapoly_encrypt
diff --git a/src/infuse_iot/rpc_wrappers/bt_disconnect.py b/src/infuse_iot/rpc_wrappers/bt_disconnect.py
index a6164e5..6ddba02 100644
--- a/src/infuse_iot/rpc_wrappers/bt_disconnect.py
+++ b/src/infuse_iot/rpc_wrappers/bt_disconnect.py
@@ -6,7 +6,6 @@
 from infuse_iot.generated.rpc_definitions import (
     rpc_struct_bt_addr_le,
     rpc_enum_bt_le_addr_type,
-    rpc_enum_infuse_bt_characteristic,
 )
 from infuse_iot.util.argparse import BtLeAddress
 from infuse_iot.util.ctypes import bytes_to_uint8
diff --git a/src/infuse_iot/rpc_wrappers/wifi_scan.py b/src/infuse_iot/rpc_wrappers/wifi_scan.py
index 41b19d5..1f49ab5 100644
--- a/src/infuse_iot/rpc_wrappers/wifi_scan.py
+++ b/src/infuse_iot/rpc_wrappers/wifi_scan.py
@@ -20,7 +20,6 @@ class response(ctypes.LittleEndianStructure):
         @classmethod
         def from_buffer_copy(cls, source, offset=0):
             values = []
-            num = source[0]
             source = source[1:]
             while len(source) > 0:
 
diff --git a/src/infuse_iot/tdf.py b/src/infuse_iot/tdf.py
index 3f7f697..3da86e5 100644
--- a/src/infuse_iot/tdf.py
+++ b/src/infuse_iot/tdf.py
@@ -3,7 +3,7 @@
 import ctypes
 import enum
 
-from typing import List, Dict
+from typing import List
 
 from infuse_iot.time import InfuseTime
 from infuse_iot.generated import tdf_definitions
diff --git a/src/infuse_iot/tools/cloud.py b/src/infuse_iot/tools/cloud.py
index 0262565..05a583e 100644
--- a/src/infuse_iot/tools/cloud.py
+++ b/src/infuse_iot/tools/cloud.py
@@ -158,7 +158,9 @@ class SubCommand(InfuseCommand):
 
     @classmethod
     def add_parser(cls, parser):
-        subparser = parser.add_subparsers(title="commands", metavar="<command>")
+        subparser = parser.add_subparsers(
+            title="commands", metavar="<command>", required=True
+        )
 
         Organisations.add_parser(subparser)
         Boards.add_parser(subparser)
diff --git a/src/infuse_iot/tools/csv_annotate.py b/src/infuse_iot/tools/csv_annotate.py
index c874bd6..f6b9a9a 100644
--- a/src/infuse_iot/tools/csv_annotate.py
+++ b/src/infuse_iot/tools/csv_annotate.py
@@ -42,7 +42,6 @@ def make_plots(self):
 
     def run(self):
         from dash import Dash, dcc, html, Input, Output, State, callback
-        import numpy as np
         import pandas as pd
 
         # Read data, add label column
@@ -53,8 +52,6 @@ def run(self):
             [self.labels[0] for _ in range(self.df.shape[0])],
         )
 
-        # print(self.df.index.iloc[0])
-
         app = Dash()
         app.layout = html.Div(
             [
diff --git a/tox.ini b/tox.ini
index 3174086..69fb1e2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 # Benefits of using tox:
 #
-# 1. makes sure we are testing west as installed by setup.py
+# 1. makes sure we are testing module as installed by pyproject.toml
 # 2. avoid touching user global / system config files
 # 3. avoid touching any git repositories outside of tmpdirs
 # 4. ensure global / system config settings have no effect on the tests
@@ -8,18 +8,27 @@
 [tox]
 envlist=py3
 
-[pycodestyle]
-# We explicitly disable the following errors:
-#
-# - E126: continuation line over-indented for hanging indent
-# - E261: at least two spaces before inline comment
-# - E302: expected 2 blank lines, found 1
-# - E305: expected 2 blank lines after class or function definition, found 1
-# - W504: line break after binary operator
-ignore = E126,E261,E302,E305,W504
-# Don't lint setup.py, the .tox or python virtualenv directory, or the build directory
-exclude = setup.py,.tox,.venv,build
-max-line-length = 120
+[tool.ruff]
+line-length = 120
+indent-width = 4
+
+[tool.ruff.lint]
+select = [
+    "B",      # flake8-bugbear
+    "E",      # pycodestyle
+    "F",      # pyflakes
+    "I",      # isort
+    "SIM",    # flake8-simplify
+    "UP",     # pyupgrade
+    "W",      # pycodestyle warnings
+    ]
+ignore = [
+    "SIM108", # Allow if-else blocks instead of forcing ternary operator
+    "UP027",  # deprecated pyupgrade rule
+    ]
+
+[tool.ruff.format]
+line-ending = "lf"
 
 [testenv]
 deps =
@@ -27,10 +36,10 @@ deps =
     pytest
     pytest-cov
     types-PyYAML
-    black
+    ruff
 setenv =
     # For instance: ./.tox/py3/tmp/
     TOXTEMPDIR={envtmpdir}
 commands =
   python -m pytest --basetemp='{envtmpdir}/pytest with space/'
-  python -m black --check '{toxinidir}' --extend-exclude 'api_client|tdf_definitions.py|rpc_definitions.py'
+  python -m ruff check '{toxinidir}' --extend-exclude 'api_client|tdf_definitions.py|rpc_definitions.py'