diff --git a/.github/workflows/lint.yaml b/.github/workflows/lint.yaml
new file mode 100644
index 0000000..60aba60
--- /dev/null
+++ b/.github/workflows/lint.yaml
@@ -0,0 +1,17 @@
+name: Linting
+on:
+  push:
+    paths: &path-list
+    - '**/*.py'
+  pull_request:
+    paths: *path-list
+
+jobs:
+  ruff:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - name: Ruff lint
+        uses: astral-sh/ruff-action@v3
+        with:
+          args: "check --output-format=github"
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..a96bda3
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,17 @@
+default_install_hook_types: [pre-commit, pre-push]
+repos:
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.14.13
+    hooks:
+      - id: ruff-check
+        args: [--fix]
+  - repo: local
+    hooks:
+      - id: pytest
+        name: Run pytest
+        entry: uv run --frozen pytest --exitfirst
+        language: python
+        types: [python]
+        stages: [pre-push]
+        pass_filenames: false
+        always_run: true
diff --git a/discid/__init__.py b/discid/__init__.py
index f19b38b..32fa0d7 100644
--- a/discid/__init__.py
+++ b/discid/__init__.py
@@ -35,6 +35,19 @@
 
 __version__ = "1.3.0"
 
+__all__ = [
+    "LIBDISCID_VERSION_STRING",
+    "FEATURES",
+    "FEATURES_IMPLEMENTED",
+    "Disc",
+    "Track",
+    "DiscError",
+    "TOCError",
+    "read",
+    "put",
+    "get_default_device",
+]
+
 
 # these constants are defined here so sphinx can catch the "docstrings"
 
diff --git a/discid/disc.py b/discid/disc.py
index b7569e7..5200d56 100644
--- a/discid/disc.py
+++ b/discid/disc.py
@@ -32,7 +32,7 @@
 
 FEATURES_IMPLEMENTED = list(_FEATURE_MAPPING.keys())
 
-def read(device=None, features=[]):
+def read(device=None, features=None):
     """Reads the TOC from the device given as string
     and returns a :class:`Disc` object.
 
@@ -123,7 +123,7 @@ def _get_error_msg(self):
         _LIB.discid_read_sparse.restype = c_int
     except AttributeError:
         pass
-    def read(self, device=None, features=[]):
+    def read(self, device=None, features=None):
         """Reads the TOC from the device given as string
 
         The user is supposed to use :func:`discid.read`.
@@ -131,6 +131,9 @@ def read(self, device=None, features=[]):
         if "read" not in FEATURES:
             raise NotImplementedError("discid_read not implemented on platform")
 
+        if features is None:
+            features = []
+
         # only use features implemented on this platform and in this module
         self._requested_features = list(set(features) & set(FEATURES)
                                         & set(FEATURES_IMPLEMENTED))
diff --git a/discid/libdiscid.py b/discid/libdiscid.py
index c7eb308..7bf040e 100644
--- a/discid/libdiscid.py
+++ b/discid/libdiscid.py
@@ -26,7 +26,7 @@
 from ctypes import c_void_p, c_char_p
 from ctypes.util import find_library
 
-from discid.util import _encode, _decode
+from discid.util import _decode
 
 _LIB_BASE_NAME = "discid"
 _LIB_MAJOR_VERSION = 0
@@ -155,7 +155,7 @@ def _get_features():
         features = ["read"]     # no generic platform yet
         try:
             # test for ISRC/MCN API (introduced 0.3.0)
-            _LIB.discid_get_mcn
+            _LIB.discid_get_mcn  # noqa: B018 (useless-expression)
         except AttributeError:
             pass
         else:
diff --git a/discid/util.py b/discid/util.py
index 552c333..fd4c22e 100644
--- a/discid/util.py
+++ b/discid/util.py
@@ -22,26 +22,26 @@
 
 SECTORS_PER_SECOND = 75
 
-def _encode(string):
+def _encode(string: str|bytes):
     """Encode (unicode) string to byte string
     """
-    try:
+    if isinstance(string, str):
         return string.encode()
-    except AttributeError:
-        # already byte string (Python 3)
+    elif isinstance(string, bytes):
         return string
+    raise TypeError('Unexpected type, expected string or bytes')
     # UnicodeDecodeError (Python 2) is NOT caught
     # device names should be ASCII
 
-def _decode(byte_string):
+def _decode(byte_string: bytes|str):
     """Decode byte string to (unicode) string
     """
     # this test for bytes works on Python 2 and 3
-    if type(byte_string) == type(b"test"):
+    if isinstance(byte_string, bytes):
         return byte_string.decode()
-    else:
-        # probably mocked for sphinx
-        return None
+    elif isinstance(byte_string, str):
+        return byte_string
+    raise TypeError('Unexpected type, expected string or bytes')
 
 def _sectors_to_seconds(sectors):
     """Round sectors to seconds like done on MusicBrainz Server
diff --git a/doc/conf.py b/doc/conf.py
index 4ac1241..c61a74d 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -1,4 +1,9 @@
-import sys, os
+import ctypes
+import sys
+import os
+
+# to gather version information
+import discid
 
 sys.path.insert(0, os.path.abspath('.'))        # for extensions
 sys.path.insert(0, os.path.abspath('..'))       # for the code
@@ -9,12 +14,8 @@ class Mock(object):
     def __call__(self, *args): return Mock()
     def __getattr__(cls, name): return Mock()
 
-import ctypes
 ctypes.cdll.LoadLibrary = Mock()
 
-# to gather version information
-import discid
-
 # -- General configuration -----------------------------------------------------
 
 needs_sphinx = "1.0"
@@ -121,4 +122,3 @@ def __getattr__(cls, name): return Mock()
 ]
 
 texinfo_domain_indices = False
-
diff --git a/pyproject.toml b/pyproject.toml
index b602488..ef52bff 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,3 +36,14 @@ docs = [
   "Sphinx~=8.1.3",
   "sphinx-rtd-theme~=3.0.2",
 ]
+dev = [
+    "pre-commit>=4.5.1",
+    "ruff>=0.14.13",
+]
+
+[tool.ruff]
+src=["discid"]
+line-length=120
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "B"]
diff --git a/test_discid.py b/test_discid.py
index 50dd106..bb870ff 100755
--- a/test_discid.py
+++ b/test_discid.py
@@ -7,6 +7,7 @@
 import unittest
 
 import discid
+import discid.util
 
 test_discs = [
         {
@@ -37,13 +38,18 @@ class TestModulePrivate(unittest.TestCase):
     # lots of encoding tests
     # not part of the actual API, but this is quite different in Python 2/3
     def test_encode(self):
-        self.assertTrue(type(discid.util._encode("test")) is type(b"test"))
+        self.assertTrue(type(discid.util._encode("test")) is bytes)
         self.assertEqual(discid.util._encode("test"), b"test")
+        self.assertEqual(discid.util._encode(b"test"), b"test")
+        with self.assertRaises(TypeError):
+            discid.util._encode(42)  # type: ignore
 
     def test_decode(self):
-        self.assertTrue(type(discid.util._decode(b"test"))
-                        is type(b"test".decode()))
+        self.assertTrue(type(discid.util._decode(b"test")) is str)
         self.assertEqual(discid.util._decode(b"test"), "test")
+        self.assertEqual(discid.util._decode("test"), "test")
+        with self.assertRaises(TypeError):
+            discid.util._encode(42)  # type: ignore
 
     def test_encoding(self):
         string = "test"