diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..b470684
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,20 @@
+[tool.ruff]
+line-length = 88
+
+select = ["E", "F", "I"]
+ignore = [ "E501" ]
+
+[tool.mypy]
+python_version = "3.10"
+warn_redundant_casts = true
+disallow_untyped_calls = true
+disallow_untyped_defs = true
+no_implicit_optional = true
+
+[[tool.mypy.overrides]]
+module = "setuptools.*"
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "pytest.*"
+ignore_missing_imports = true
diff --git a/run-tests.nix b/run-tests.nix
index 189198e..ae908cc 100644
--- a/run-tests.nix
+++ b/run-tests.nix
@@ -4,6 +4,8 @@
   direnv,
   mypy,
   python3,
+  lib,
+  ruff
 }:
 writeScript "run-tests" ''
   set -e
@@ -11,12 +13,12 @@ writeScript "run-tests" ''
   echo run shellcheck
   ${shellcheck}/bin/shellcheck direnvrc
   echo run black
-  LC_ALL=en_US.utf-8 ${python3.pkgs.black}/bin/black --check .
-  echo run flake8
-  ${python3.pkgs.flake8}/bin/flake8 --ignore E501 tests
+  LC_ALL=en_US.utf-8 ${lib.getExe python3.pkgs.black} --check .
+  echo run ruff
+  ${lib.getExe ruff} tests
   echo run mypy
-  ${mypy}/bin/mypy tests
+  ${lib.getExe mypy} tests
 
   echo run unittest
-  ${python3.pkgs.pytest}/bin/pytest .
+  ${lib.getExe python3.pkgs.pytest} .
 ''