diff --git a/requirements.txt b/requirements.txt
index d511302..b6aa5b1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1,16 @@
+astroid==2.15.1
+dill==0.3.6
+flake8==6.0.0
+isort==5.12.0
+lazy-object-proxy==1.9.0
+mccabe==0.7.0
+mypy==1.1.1
+mypy-extensions==1.0.0
 orjson==3.8.9
+platformdirs==3.2.0
+pycodestyle==2.10.0
+pyflakes==3.0.1
+pylint==2.17.1
+tomlkit==0.11.7
+typing_extensions==4.5.0
+wrapt==1.15.0
diff --git a/scripts/check.sh b/scripts/check.sh
new file mode 100755
index 0000000..057c6ea
--- /dev/null
+++ b/scripts/check.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+# Copyright 2023 Levi Gruspe
+# Licensed under GNU GPLv3 or later
+# See https://www.gnu.org/licenses/gpl-3.0.en.html
+
+# Check code.
+
+mypy --strict word2ipa
+flake8 word2ipa
+pylint word2ipa