diff --git a/docs/api.rst b/docs/api.rst
index b84476c..2c74b36 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -6,4 +6,7 @@ API Documentation
 
    apis/changelog.md
    apis/metric.rst
+   apis/optim.rst
+   apis/input.rst
+   apis/tree.rst