diff --git a/.gitignore b/.gitignore
index 1b5e22b..841e961 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 __pycache__/
 venv/
+.tox/
 .hypothesis/
 .mutmut-cache
 dist/
diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..6830466
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,93 @@
+[tox]
+requires = tox
+labels =
+    check = flake8, black, test
+    ci = build, flake8, black_ci, test_ci, mutmut
+
+[testenv:run]
+description = Runs the project
+use_develop = true
+commands = python -m newlang {posargs}
+
+[testenv:build]
+description = Builds the project
+deps =
+    build
+    wheel
+commands = python -m build
+
+[testenv:flake8]
+description = Runs flake8
+skip_install = true
+deps = flake8
+commands = flake8 {posargs:src tests}
+
+[testenv:black]
+description = Runs black
+skip_install = true
+deps = black
+commands = black {posargs:src tests}
+
+[testenv:black_ci]
+description = Runs black in checking mode
+deps = black
+commands = black --check {posargs:src tests}
+
+[testenv:test]
+description = Tests the project
+deps =
+    pytest
+    pytest-randomly
+    pytest-xdist
+    hypothesis
+commands =
+    pytest -q -n auto -x -l --sw --hypothesis-profile=dev {posargs}
+
+[testenv:test_dev]
+description = Tests the current source tree slowly
+use_develop = true
+deps =
+    pytest
+    pytest-randomly
+    pytest-xdist
+    hypothesis
+commands =
+    pytest -vv -n 0 -x -l --sw --hypothesis-profile=dev {posargs}
+
+[testenv:test_ci]
+description = Tests the project for a long time
+deps =
+    pytest
+    pytest-randomly
+    pytest-xdist
+    hypothesis
+commands =
+    pytest -q -n auto -x -l --sw --hypothesis-profile=ci {posargs}
+
+[testenv:mutmut]
+description = Runs mutmut on the source tree
+use_develop = true
+deps =
+    pytest
+    pytest-randomly
+    pytest-xdist
+    hypothesis
+    mutmut
+commands =
+    mutmut run --paths-to-mutate "src/parse2,src/newlang/i18n.py"
+commands_post =
+    mutmut results
+
+[testenv:mutmut_ci]
+description = Runs mutmut on the source tree without progress
+use_develop = true
+deps =
+    pytest
+    pytest-randomly
+    pytest-xdist
+    hypothesis
+    mutmut
+commands =
+    mutmut run --no-progress --paths-to-mutate "src/parse2,src/newlang/i18n.py"
+commands_post =
+    mutmut results