diff --git a/requirements-docs.in b/requirements-docs.in
index b6c8d2f4..46650ccc 100644
--- a/requirements-docs.in
+++ b/requirements-docs.in
@@ -17,6 +17,8 @@ Flask-SQLAlchemy
 flask_replicated
 inflection
 logmatic-python
+marshmallow-sqlalchemy
+marshmallow<2.20.5 #schema duplicate issues https://github.com/marshmallow-code/marshmallow-sqlalchemy/issues/121
 pem
 raven[flask]
 SQLAlchemy-Utils
diff --git a/requirements-docs.txt b/requirements-docs.txt
index 7d99dd51..f175d8d0 100644
--- a/requirements-docs.txt
+++ b/requirements-docs.txt
@@ -50,6 +50,10 @@ logmatic-python==0.1.7
     # manual debug
 markupsafe==1.1.1
     # via jinja2
+marshmallow-sqlalchemy==0.23.1
+    # manual debug
+marshmallow==2.20.4
+    # manual debug
 packaging==20.3
     # via sphinx
 pem==21.1.0