diff --git a/doc/source/conf.py b/doc/source/conf.py
index 56c7e0456..47e7ba6a9 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -48,6 +48,7 @@ extensions = [
     'sphinxcontrib.pecanwsme.rest',
     'stevedore.sphinxext',
     'oslo_config.sphinxconfiggen',
+    'sphinxcontrib.httpdomain',
 ]
 
 config_generator_config_file = os.path.join(ROOT,