diff --git a/.gitignore b/.gitignore
index b9bab86..f57529d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -245,3 +245,4 @@ ENV/
 # End of https://www.gitignore.io/api/node,linux,python,jetbrains,archlinuxpackages
 
 out/
+.mypy_cache
diff --git a/circle.yml b/circle.yml
index 259dbb0..55fc5f3 100644
--- a/circle.yml
+++ b/circle.yml
@@ -21,6 +21,7 @@ test:
   override:
     - npm test
     - flake8 md_pdf/ --ignore=E128,E501
+    - mypy --ignore-missing-imports md_pdf
     - safety check
     - bandit -r md_pdf/
     - mdp --update-csl -vvv
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 217ed69..e6a2a71 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,4 +1,5 @@
 bandit==1.4.0
 flake8==3.3.0
 freezegun==0.3.9
+mypy==0.511
 safety==0.5.1