diff --git a/requirements.in b/requirements.in
index bca803b..b67542b 100644
--- a/requirements.in
+++ b/requirements.in
@@ -13,3 +13,4 @@ pre-commit
 pytz
 opencage
 flask
+flask_classful
diff --git a/requirements.txt b/requirements.txt
index 9e34f8b..ab1554d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -35,8 +35,12 @@ filelock==3.0.12
     # via
     #   py3-validate-email
     #   virtualenv
-flask==1.1.2
+flask-classful==0.14.2
     # via -r requirements.in
+flask==1.1.2
+    # via
+    #   -r requirements.in
+    #   flask-classful
 identify==1.5.13
     # via pre-commit
 idna==2.10