diff --git a/Makefile b/Makefile
index d0874e03f..fdbdbecb2 100644
--- a/Makefile
+++ b/Makefile
@@ -46,8 +46,8 @@ clean-test: ## remove test and coverage artifacts
 	rm -f .coverage
 	rm -fr htmlcov/
 
-lint: ## check style with flake8
-	flake8 pythainlp tests
+lint: ## check style
+	ruff check pythainlp tests notebooks
 
 test: ## run tests quickly with the default Python
 	python -m unittest discover
diff --git a/pyproject.toml b/pyproject.toml
index 9724eb0ea..a1c233fd9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -74,7 +74,7 @@ dev = [
     "build>=1.0.0",
     "bump-my-version>=1.2.6",
     "coverage>=7.10.7",
-    "flake8>=7.3.0",
+    "mypy>=1.19.1",
     "ruff>=0.14.14",
     "tox>=4.30.3",
 ]
@@ -345,23 +345,21 @@ select = [
 extend-ignore = ["E402", "E501", "E722", "S101", "S202", "S301", "S310"]
 
 [tool.tox]
-envlist = ["py39", "py310", "py311", "py312", "py313", "py314", "py3", "pypy3", "flake8"]
+env_list = ["py39", "py310", "py311", "py312", "py313", "py314", "pypy310", "pypy311", "ruff"]
 skip_missing_interpreters = true
 
-[tool.tox.testenv]
-setenv = { PYTHONPATH = "{toxinidir}:{toxinidir}/pythainlp" }
-changedir = "tests"
-commands = ["discover"]
-deps = ["discover"]
+[tool.tox.env_run_base]
+commands = [["python", "-m", "unittest", "tests.core", "tests.compact"]]
+extras = ["compact"]
 
-[tool.tox.envs.pypy3]
+[tool.tox.env.pypy310]
 basepython = "pypy3.10"
-setenv = { PYTHONPATH = "{toxinidir}:{toxinidir}/pythainlp" }
-changedir = "tests"
-commands = ["discover"]
-deps = ["discover"]
 
-[tool.tox.envs.flake8]
+[tool.tox.env.pypy311]
+basepython = "pypy3.11"
+
+[tool.tox.env.ruff]
 basepython = "python"
-deps = ["flake8"]
-commands = ["flake8 pythainlp"]
+deps = ["ruff"]
+commands = [["ruff", "check", "pythainlp"], ["ruff", "format", "--check", "pythainlp"]]
+skip_install = true