diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index bf522c6..32fc77b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,11 +18,12 @@ jobs:
   build-test:
     runs-on: ${{ matrix.os }}
     strategy:
-      matrix:
-        # Python 3.8 is the last non-EOL version. Also adapt tox.ini
-        python-version: ['3.8', 'pypy3.10', '3.12']
-        os: [ubuntu-latest, windows-latest]
       fail-fast: false
+      matrix:
+        # Python 3.8 is EOL. Also adapt tox.ini
+        python-version: ['3.8', 'pypy3.11', '3.x']
+        # macOS on ARM, Ubuntu on x86, Windows on X86
+        os: [macos-latest, ubuntu-latest, windows-latest]
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -32,13 +33,11 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-          architecture: x64
           cache: 'pip'
-          cache-dependency-path: '**/test-requirements'
+          cache-dependency-path: 'pyproject.toml'
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          python -m pip install -e .[dev]
-          python -m pip install 'tox-gh-actions<4.0.0'
+          python -m pip install --editable .[dev]
       - name: Test with tox
-        run: tox
+        run: tox -e py
diff --git a/cpplint.py b/cpplint.py
index 7a8b8ab..0e658d2 100755
--- a/cpplint.py
+++ b/cpplint.py
@@ -44,7 +44,7 @@
 import codecs
 import collections
 import copy
-import getopt
+import getopt  # pylint: disable=deprecated-module
 import glob
 import itertools
 import math  # for log
diff --git a/dev-requirements b/dev-requirements
deleted file mode 100644
index 62a36ea..0000000
--- a/dev-requirements
+++ /dev/null
@@ -1,5 +0,0 @@
-# requirements to run development steps
-
-flake8>=4.0.1
-pylint>=2.11.0
-setuptools
diff --git a/pyproject.toml b/pyproject.toml
index e4bb940..91f944a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,77 @@
 [build-system]
-build-backend = "setuptools.build_meta:__legacy__"
-requires = [
+build-backend = "setuptools.build_meta"
+requires = [ "setuptools>=61.2" ]
+
+[project]
+name = "cpplint"
+version = "2.0.0"
+description = "Automated checker to ensure C++ files follow Google's style guide"
+readme = "README.rst"
+keywords = [ "c++", "lint", "python" ]
+license = { text = "BSD-3-Clause" }
+maintainers = [ { name = "cpplint Developers" } ]
+requires-python = ">=3.8"
+classifiers = [
+  "Development Status :: 5 - Production/Stable",
+  "Environment :: Console",
+  "Intended Audience :: End Users/Desktop",
+  "License :: Freely Distributable",
+  "License :: OSI Approved :: BSD License",
+  "Natural Language :: English",
+  "Programming Language :: C++",
+  "Programming Language :: Python :: 3 :: Only",
+  "Programming Language :: Python :: 3.8",
+  "Programming Language :: Python :: 3.9",
+  "Programming Language :: Python :: 3.10",
+  "Programming Language :: Python :: 3.11",
+  "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.13",
+  "Topic :: Software Development :: Quality Assurance",
+]
+dependencies = [  ]
+
+optional-dependencies.dev = [
+  "flake8>=4.0.1",
+  "parameterized",
+  "pylint>=2.11",
+  "pytest",
+  "pytest-cov",
+  "pytest-timeout",
   "setuptools",
-  "wheel",
+  "testfixtures",
+  "tox<5",
+]
+optional-dependencies.test = [
+  "parameterized",
+  "pytest",
+  "pytest-cov",
+  "pytest-timeout",
+  "testfixtures",
+  "tox<5",
+]
+optional-dependencies.testing = [
+  "parameterized",
+  "pytest",
+  "pytest-cov",
+  "pytest-timeout",
+  "testfixtures",
+  "tox<5",
 ]
+urls.Download = "https://github.com/cpplint/cpplint"
+urls.Homepage = "https://github.com/cpplint/cpplint"
+scripts.cpplint = "cpplint:main"
+
+[tool.setuptools]
+py-modules = [ "cpplint" ]
+include-package-data = false
+
+[tool.pytest.ini_options]
+python_files = [ "*test.py" ]
+testpaths = [ "." ]
+required_plugins = [ "pytest-cov", "pytest-timeout" ]
+timeout = 60
+# fail if coverage is under 90%
+addopts = "--color=yes --cov-fail-under=90 --cov=cpplint"
+
+[tool.aliases]
+test = "pytest"
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index eebbf0a..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,10 +0,0 @@
-[aliases]
-test = pytest
-
-[tool:pytest]
-python_files = *test.py
-testpaths = .
-required_plugins = pytest-cov pytest-timeout
-timeout = 60
-# fail if coverage is under 90%
-addopts = --color=yes --cov-fail-under=90 --cov=cpplint
diff --git a/setup.py b/setup.py
deleted file mode 100755
index 2325a71..0000000
--- a/setup.py
+++ /dev/null
@@ -1,48 +0,0 @@
-#! /usr/bin/env python
-from setuptools import setup
-import cpplint
-
-# some pip versions bark on comments
-def read_without_comments(filename):
-    with open(filename) as f:
-        return [line for line in f.read().splitlines() if not len(line) == 0 and not line.startswith('#')]
-
-test_required = read_without_comments('test-requirements')
-
-setup(name='cpplint',
-      version=cpplint.__VERSION__,
-      py_modules=['cpplint'],
-      # generate platform specific start script
-      entry_points={
-          'console_scripts': [
-              'cpplint = cpplint:main'
-          ]
-      },
-      install_requires=[],
-      url='https://github.com/cpplint/cpplint',
-      download_url='https://github.com/cpplint/cpplint',
-      keywords=['lint', 'python', 'c++'],
-      maintainer='cpplint Developers',
-      classifiers=['Development Status :: 5 - Production/Stable',
-                   'Environment :: Console',
-                   'Intended Audience :: End Users/Desktop',
-                   'License :: Freely Distributable',
-                   'License :: OSI Approved :: BSD License',
-                   'Natural Language :: English',
-                   'Programming Language :: Python :: 3 :: Only',
-                   'Programming Language :: Python :: 3.8',
-                   'Programming Language :: Python :: 3.9',
-                   'Programming Language :: Python :: 3.10',
-                   'Programming Language :: Python :: 3.11',
-                   'Programming Language :: Python :: 3.12',
-                   'Programming Language :: C++',
-                   'Topic :: Software Development :: Quality Assurance'],
-      description='Automated checker to ensure C++ files follow Google\'s style guide',
-      long_description=open('README.rst').read(),
-      license='BSD-3-Clause',
-      tests_require=test_required,
-      # extras_require allow pip install .[dev]
-      extras_require={
-          'test': test_required,
-          'dev': read_without_comments('dev-requirements') + test_required
-      })
diff --git a/test-requirements b/test-requirements
deleted file mode 100644
index 9c9abb5..0000000
--- a/test-requirements
+++ /dev/null
@@ -1,8 +0,0 @@
-# requirements for testing steps
-tox<5.0.0
-
-pytest
-pytest-cov
-pytest-timeout
-testfixtures
-parameterized
diff --git a/tox.ini b/tox.ini
index d7e3e82..1fc6c00 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,16 +1,7 @@
 [tox]
-envlist = py38, py39, py3.10, py311, py312, pypy3
+envlist = py38, py39, py3.10, py311, py312, py313, pypy3
 skip_missing_interpreters = true
 
-[gh-actions]
-python =
-    3.8: py38
-    3.9: py39
-    3.10: py310
-    3.11: py311
-    3.12: py312
-    pypy3.10: pypy3
-
 [testenv]
 extras = dev