diff --git a/adhoc/blosc_memleak_check.py b/adhoc/blosc_memleak_check.py
index 427c3e153..a6409ed19 100644
--- a/adhoc/blosc_memleak_check.py
+++ b/adhoc/blosc_memleak_check.py
@@ -1,10 +1,9 @@
 import sys
 
+import numcodecs
 import numpy as np
 from numpy.testing import assert_array_equal
 
-import numcodecs
-
 codec = numcodecs.Blosc()
 data = np.arange(int(sys.argv[1]))
 for _ in range(int(sys.argv[2])):
diff --git a/notebooks/benchmark_vlen.ipynb b/notebooks/benchmark_vlen.ipynb
index c627cac95..cb971278e 100644
--- a/notebooks/benchmark_vlen.ipynb
+++ b/notebooks/benchmark_vlen.ipynb
@@ -24,9 +24,8 @@
     }
    ],
    "source": [
-    "import numpy as np\n",
-    "\n",
     "import numcodecs\n",
+    "import numpy as np\n",
     "\n",
     "numcodecs.__version__"
    ]
diff --git a/numcodecs/astype.py b/numcodecs/astype.py
index b5c5abc97..4947d53c9 100644
--- a/numcodecs/astype.py
+++ b/numcodecs/astype.py
@@ -49,9 +49,7 @@ def encode(self, buf):
         arr = ensure_ndarray(buf).view(self.decode_dtype)
 
         # convert and copy
-        enc = arr.astype(self.encode_dtype)
-
-        return enc
+        return arr.astype(self.encode_dtype)
 
     def decode(self, buf, out=None):
         # normalise input
@@ -61,9 +59,7 @@ def decode(self, buf, out=None):
         dec = enc.astype(self.decode_dtype)
 
         # handle output
-        out = ndarray_copy(dec, out)
-
-        return out
+        return ndarray_copy(dec, out)
 
     def get_config(self):
         return {
diff --git a/numcodecs/base64.py b/numcodecs/base64.py
index 74f42161c..307c6d52b 100644
--- a/numcodecs/base64.py
+++ b/numcodecs/base64.py
@@ -13,8 +13,7 @@ def encode(self, buf):
         # normalise inputs
         buf = ensure_contiguous_ndarray(buf)
         # do compression
-        compressed = _base64.standard_b64encode(buf)
-        return compressed
+        return _base64.standard_b64encode(buf)
 
     def decode(self, buf, out=None):
         # normalise inputs
diff --git a/numcodecs/categorize.py b/numcodecs/categorize.py
index ed20ad61b..c81994937 100644
--- a/numcodecs/categorize.py
+++ b/numcodecs/categorize.py
@@ -80,18 +80,15 @@ def decode(self, buf, out=None):
             dec[enc == (i + 1)] = label
 
         # handle output
-        dec = ndarray_copy(dec, out)
-
-        return dec
+        return ndarray_copy(dec, out)
 
     def get_config(self):
-        config = {
+        return {
             'id': self.codec_id,
             'labels': self.labels,
             'dtype': self.dtype.str,
             'astype': self.astype.str,
         }
-        return config
 
     def __repr__(self):
         # make sure labels part is not too long
diff --git a/numcodecs/delta.py b/numcodecs/delta.py
index ee4abbc76..32da2e04b 100644
--- a/numcodecs/delta.py
+++ b/numcodecs/delta.py
@@ -85,9 +85,7 @@ def decode(self, buf, out=None):
         np.cumsum(enc, out=dec)
 
         # handle output
-        out = ndarray_copy(dec, out)
-
-        return out
+        return ndarray_copy(dec, out)
 
     def get_config(self):
         # override to handle encoding dtypes
diff --git a/numcodecs/fixedscaleoffset.py b/numcodecs/fixedscaleoffset.py
index 636e439ee..b1db52050 100644
--- a/numcodecs/fixedscaleoffset.py
+++ b/numcodecs/fixedscaleoffset.py
@@ -94,9 +94,7 @@ def encode(self, buf):
         enc = np.around(enc)
 
         # convert dtype
-        enc = enc.astype(self.astype, copy=False)
-
-        return enc
+        return enc.astype(self.astype, copy=False)
 
     def decode(self, buf, out=None):
         # interpret buffer as numpy array
diff --git a/numcodecs/gzip.py b/numcodecs/gzip.py
index 12e9c011e..4269bad93 100644
--- a/numcodecs/gzip.py
+++ b/numcodecs/gzip.py
@@ -28,9 +28,7 @@ def encode(self, buf):
         compressed = io.BytesIO()
         with _gzip.GzipFile(fileobj=compressed, mode='wb', compresslevel=self.level) as compressor:
             compressor.write(buf)
-        compressed = compressed.getvalue()
-
-        return compressed
+        return compressed.getvalue()
 
     # noinspection PyMethodMayBeStatic
     def decode(self, buf, out=None):
diff --git a/numcodecs/lzma.py b/numcodecs/lzma.py
index 32fb528b2..5c1a57caf 100644
--- a/numcodecs/lzma.py
+++ b/numcodecs/lzma.py
@@ -5,7 +5,7 @@
 try:
     import lzma as _lzma
 except ImportError:  # pragma: no cover
-    try:
+    try:  # noqa: SIM105
         from backports import lzma as _lzma  # type: ignore[no-redef]
     except ImportError:
         pass
diff --git a/numcodecs/ndarray_like.py b/numcodecs/ndarray_like.py
index f70d7b450..06e15ea97 100644
--- a/numcodecs/ndarray_like.py
+++ b/numcodecs/ndarray_like.py
@@ -1,4 +1,4 @@
-from typing import Any, ClassVar, Optional, Protocol, runtime_checkable
+from typing import Any, ClassVar, Protocol, runtime_checkable
 
 
 class _CachedProtocolMeta(Protocol.__class__):  # type: ignore[name-defined]
@@ -53,7 +53,7 @@ def __getitem__(self, key) -> Any: ...  # pragma: no cover
 
     def __setitem__(self, key, value): ...  # pragma: no cover
 
-    def tobytes(self, order: Optional[str] = ...) -> bytes: ...  # pragma: no cover
+    def tobytes(self, order: str | None = ...) -> bytes: ...  # pragma: no cover
 
     def reshape(self, *shape: int, order: str = ...) -> "NDArrayLike": ...  # pragma: no cover
 
diff --git a/numcodecs/pcodec.py b/numcodecs/pcodec.py
index 1739ff0bd..da063ae53 100644
--- a/numcodecs/pcodec.py
+++ b/numcodecs/pcodec.py
@@ -1,4 +1,4 @@
-from typing import Literal, Optional
+from typing import Literal
 
 from numcodecs.abc import Codec
 from numcodecs.compat import ensure_contiguous_ndarray
@@ -55,7 +55,7 @@ def __init__(
         mode_spec: Literal["auto", "classic"] = "auto",
         delta_spec: Literal["auto", "none", "try_consecutive", "try_lookback"] = "auto",
         paging_spec: Literal["equal_pages_up_to"] = "equal_pages_up_to",
-        delta_encoding_order: Optional[int] = None,
+        delta_encoding_order: int | None = None,
         equal_pages_up_to: int = DEFAULT_MAX_PAGE_N,
     ):
         if standalone is None:  # pragma: no cover
@@ -105,13 +105,12 @@ def _get_chunk_config(self):
             case _:
                 raise ValueError(f"paging_spec {self.paging_spec} is not supported")
 
-        config = ChunkConfig(
+        return ChunkConfig(
             compression_level=self.level,
             delta_spec=delta_spec,
             mode_spec=mode_spec,
             paging_spec=paging_spec,
         )
-        return config
 
     def encode(self, buf):
         buf = ensure_contiguous_ndarray(buf)
diff --git a/numcodecs/quantize.py b/numcodecs/quantize.py
index b9a8a3113..b5b6cc3cc 100644
--- a/numcodecs/quantize.py
+++ b/numcodecs/quantize.py
@@ -73,9 +73,7 @@ def encode(self, buf):
         enc = np.around(scale * arr) / scale
 
         # cast dtype
-        enc = enc.astype(self.astype, copy=False)
-
-        return enc
+        return enc.astype(self.astype, copy=False)
 
     def decode(self, buf, out=None):
         # filter is lossy, decoding is no-op
diff --git a/numcodecs/tests/common.py b/numcodecs/tests/common.py
index 2de810522..bb7c4780b 100644
--- a/numcodecs/tests/common.py
+++ b/numcodecs/tests/common.py
@@ -7,8 +7,7 @@
 import pytest
 from numpy.testing import assert_array_almost_equal, assert_array_equal
 
-# star import needed for repr tests so eval finds names
-from numcodecs import *  # noqa: F403
+from numcodecs import *  # noqa: F403  # for eval to find names in repr tests
 from numcodecs.compat import ensure_bytes, ensure_ndarray
 from numcodecs.registry import get_codec
 
@@ -19,9 +18,9 @@
     'Hei maailma!',
     'Xin chào thế giới',
     'Njatjeta Botë!',
-    'Γεια σου κόσμε!',
+    'Γεια σου κόσμε!',  # noqa: RUF001
     'こんにちは世界',
-    '世界，你好！',
+    '世界，你好！',  # noqa: RUF001
     'Helló, világ!',
     'Zdravo svete!',
     'เฮลโลเวิลด์',
diff --git a/numcodecs/tests/test_blosc.py b/numcodecs/tests/test_blosc.py
index 17b291388..8c1872014 100644
--- a/numcodecs/tests/test_blosc.py
+++ b/numcodecs/tests/test_blosc.py
@@ -215,14 +215,12 @@ def test_backwards_compatibility():
 
 def _encode_worker(data):
     compressor = Blosc(cname='zlib', clevel=9, shuffle=Blosc.SHUFFLE)
-    enc = compressor.encode(data)
-    return enc
+    return compressor.encode(data)
 
 
 def _decode_worker(enc):
     compressor = Blosc()
-    data = compressor.decode(enc)
-    return data
+    return compressor.decode(enc)
 
 
 @pytest.mark.parametrize('pool', [Pool, ThreadPool])
diff --git a/numcodecs/tests/test_shuffle.py b/numcodecs/tests/test_shuffle.py
index 1194e5982..6e6d744a1 100644
--- a/numcodecs/tests/test_shuffle.py
+++ b/numcodecs/tests/test_shuffle.py
@@ -79,14 +79,12 @@ def test_eq():
 
 def _encode_worker(data):
     compressor = Shuffle()
-    enc = compressor.encode(data)
-    return enc
+    return compressor.encode(data)
 
 
 def _decode_worker(enc):
     compressor = Shuffle()
-    data = compressor.decode(enc)
-    return data
+    return compressor.decode(enc)
 
 
 @pytest.mark.parametrize('pool', [Pool, ThreadPool])
diff --git a/numcodecs/zarr3.py b/numcodecs/zarr3.py
index 0fc0acee8..d297b39e1 100644
--- a/numcodecs/zarr3.py
+++ b/numcodecs/zarr3.py
@@ -40,8 +40,10 @@
 
     if zarr.__version__ < "3.0.0":  # pragma: no cover
         raise ImportError("zarr 3.0.0 or later is required to use the numcodecs zarr integration.")
-except ImportError:  # pragma: no cover
-    raise ImportError("zarr 3.0.0 or later is required to use the numcodecs zarr integration.")
+except ImportError as e:  # pragma: no cover
+    raise ImportError(
+        "zarr 3.0.0 or later is required to use the numcodecs zarr integration."
+    ) from e
 
 from zarr.abc.codec import ArrayArrayCodec, ArrayBytesCodec, BytesBytesCodec
 from zarr.abc.metadata import Metadata
@@ -95,6 +97,7 @@ def __init__(self, **codec_config: JSON) -> None:
             "Numcodecs codecs are not in the Zarr version 3 specification and "
             "may not be supported by other zarr implementations.",
             category=UserWarning,
+            stacklevel=2,
         )
 
     @cached_property
diff --git a/pyproject.toml b/pyproject.toml
index 52ab34c39..7dfadb5d4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -164,39 +164,68 @@ environment = { DISABLE_NUMCODECS_AVX2=1, DISABLE_NUMCODECS_SSE2=1 }
 
 [tool.ruff]
 line-length = 100
+extend-exclude = ["c-blosc"]
+src = ["numcodecs"]
 
 [tool.ruff.lint]
 extend-select = [
     "B",
     "C4",
+    "EXE",
+    "FA",
     "FLY",
     "FURB",
     "G",
     "I",
+    "ISC",
+    "LOG",
     "PERF",
     "PGH",
     "PIE",
     "PT",
     "PYI",
+    "RET",
     "RSE",
     "RUF",
+    "SIM",
+    "SLOT",
+    "TID",
+    "TRY",
     "UP",
-    # "W",  https://github.com/astral-sh/ruff/issues/13763
 ]
 ignore = [
-    "B028",
-    "B904",
     "FURB101",
     "FURB103",
     "PT001",
-    "PT004",  # deprecated
-    "PT005",  # deprecated
     "PT011",
-	"RUF001",
+    "PT012",
+    "RET505",
+    "RET506",
+    "SIM108",
+    "TRY003",
+    "TRY301",
     "UP007",
-    "UP027",  # deprecated
     "UP038",  # https://github.com/astral-sh/ruff/issues/7871
-]
+    # https://docs.astral.sh/ruff/formatter/#conflicting-lint-rules
+    "W191",
+    "E111",
+    "E114",
+    "E117",
+    "D206",
+    "D300",
+    "Q000",
+    "Q001",
+    "Q002",
+    "Q003",
+    "COM812",
+    "COM819",
+    "ISC001",
+    "ISC002",
+]
+
+[tool.ruff.lint.extend-per-file-ignores]
+"numcodecs/tests/**" = ["SIM201", "SIM202", "SIM300", "TRY002"]
+"notebooks/**" = ["W391"]  # https://github.com/astral-sh/ruff/issues/13763
 
 [tool.ruff.format]
 quote-style = "preserve"
diff --git a/setup.py b/setup.py
index 0f5ec481d..6cbddf4a5 100644
--- a/setup.py
+++ b/setup.py
@@ -111,7 +111,7 @@ def blosc_extension():
     sources = ['numcodecs/blosc.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.blosc',
             sources=sources + blosc_sources,
@@ -122,8 +122,6 @@ def blosc_extension():
         ),
     ]
 
-    return extensions
-
 
 def zstd_extension():
     info('setting up Zstandard extension')
@@ -153,7 +151,7 @@ def zstd_extension():
         extra_objects = []
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.zstd',
             sources=sources + zstd_sources,
@@ -164,8 +162,6 @@ def zstd_extension():
         ),
     ]
 
-    return extensions
-
 
 def lz4_extension():
     info('setting up LZ4 extension')
@@ -182,7 +178,7 @@ def lz4_extension():
     sources = ['numcodecs/lz4.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.lz4',
             sources=sources + lz4_sources,
@@ -192,8 +188,6 @@ def lz4_extension():
         ),
     ]
 
-    return extensions
-
 
 def vlen_extension():
     info('setting up vlen extension')
@@ -209,7 +203,7 @@ def vlen_extension():
     sources = ['numcodecs/vlen.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.vlen',
             sources=sources,
@@ -219,8 +213,6 @@ def vlen_extension():
         ),
     ]
 
-    return extensions
-
 
 def fletcher_extension():
     info('setting up fletcher32 extension')
@@ -235,7 +227,7 @@ def fletcher_extension():
     sources = ['numcodecs/fletcher32.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.fletcher32',
             sources=sources,
@@ -245,8 +237,6 @@ def fletcher_extension():
         ),
     ]
 
-    return extensions
-
 
 def jenkins_extension():
     info('setting up jenkins extension')
@@ -261,7 +251,7 @@ def jenkins_extension():
     sources = ['numcodecs/jenkins.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.jenkins',
             sources=sources,
@@ -271,8 +261,6 @@ def jenkins_extension():
         ),
     ]
 
-    return extensions
-
 
 def compat_extension():
     info('setting up compat extension')
@@ -282,7 +270,7 @@ def compat_extension():
     sources = ['numcodecs/compat_ext.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension(
             'numcodecs.compat_ext',
             sources=sources,
@@ -290,8 +278,6 @@ def compat_extension():
         ),
     ]
 
-    return extensions
-
 
 def shuffle_extension():
     info('setting up shuffle extension')
@@ -301,12 +287,10 @@ def shuffle_extension():
     sources = ['numcodecs/_shuffle.pyx']
 
     # define extension module
-    extensions = [
+    return [
         Extension('numcodecs._shuffle', sources=sources, extra_compile_args=extra_compile_args),
     ]
 
-    return extensions
-
 
 if sys.platform == 'win32':
     ext_errors = (CCompilerError, ExecError, PlatformError, IOError, ValueError)