diff --git a/mypy.ini b/mypy.ini
new file mode 100644
index 0000000..37a15a5
--- /dev/null
+++ b/mypy.ini
@@ -0,0 +1,3 @@
+[mypy]
+namespace_packages = True
+warn_unused_ignores = True
diff --git a/swh/__init__.py b/swh/__init__.py
index 69e3be5..e780381 100644
--- a/swh/__init__.py
+++ b/swh/__init__.py
@@ -1 +1,4 @@
-__path__ = __import__('pkgutil').extend_path(__path__, __name__)
+from pkgutil import extend_path
+from typing import Iterable
+
+__path__: Iterable[str] = extend_path(__path__, __name__)
diff --git a/tox.ini b/tox.ini
index c12e4f0..7c99df6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,24 +1,32 @@
 [tox]
-envlist=flake8,py3
+envlist=flake8,mypy,py3
 
 [testenv:py3]
 deps =
   pytest-cov
 commands =
   pytest --cov=swh --cov-branch {posargs}
 
 [testenv:flake8]
 skip_install = true
 deps =
   flake8
 commands =
   {envpython} -m flake8
 
 
 [testenv:flake8-phab]
 skip_install = true
 deps =
   flake8
   git+https://framagit.org/douardda/flake8-phabricator-formatter.git
 commands =
   {envpython} -m flake8 --format=phabricator --output-file=.phabricator-lint
+
+[testenv:mypy]
+extras =
+  testing
+deps =
+  mypy
+commands =
+  mypy swh