diff --git a/incorporealcms/config.py b/incorporealcms/config.py
index 05a0d3d..aa4530c 100644
--- a/incorporealcms/config.py
+++ b/incorporealcms/config.py
@@ -32,8 +32,14 @@ class Config(object):
         },
     }
 
-    MARKDOWN_EXTENSIONS = ['mdx_linkify', 'tables']
-    MARKDOWN_EXTENSION_CONFIGS = {}
+    MARKDOWN_EXTENSIONS = ['extra', 'mdx_linkify', 'tables']
+    MARKDOWN_EXTENSION_CONFIGS = {
+        'extra': {
+            'footnotes': {
+                'UNIQUE_IDS': True,
+            },
+        }
+    }
 
     DEFAULT_PAGE_STYLE = 'light'