diff --git a/docs/api.rst b/docs/api.rst
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -31,6 +31,12 @@
   sub-directories when traversing the forward graph, but the same restriction
   allows following edges from sub-directories to parent directories.
 
+  We can also specify how many edges a visit can traversed, in order to avoid Dos.
+
+- **Node filtering**: a textual specification of which type of nodes can be printed after a request.
+  Either ``*`` to denote that all types of nodes can be printed or a comma separated list of
+  node types to allow following only those nodes.
+
 
 Examples
 ~~~~~~~~
@@ -45,6 +51,7 @@
 - ``"rev:rev,dir:*"`` node types allowing edges from revisions to revisions
   nodes, or from directories nodes.
 - ``"*:rel"`` node types allowing all edges to releases.
+- ``"cnt,snp"`` node types allowed the swhid of content and snapshot nodes to be printed in the request response.
 
 
 Leaves
@@ -61,6 +68,8 @@
         ``"*"``
     :query string direction: direction in which graph edges will be followed;
         can be either ``forward`` or ``backward``, default to ``forward``
+    :query integer max_edges: how many edges can be traversed during the visit; default to 0 (not restricted)
+    :query string return_types: types of nodes we want to be displayed; default to ``"*"``
 
     :statuscode 200: success
     :statuscode 400: invalid query string provided
@@ -99,6 +108,8 @@
         to ``"*"``
     :query string direction: direction in which graph edges will be followed;
         can be either ``forward`` or ``backward``, default to ``forward``
+    :query integer max_edges: how many edges can be traversed during the visit; default to 0 (not restricted)
+    :query string return_types: types of nodes we want to be displayed; default to ``"*"``
 
     :statuscode 200: success
     :statuscode 400: invalid query string provided
@@ -143,6 +154,8 @@
           ``bfs``, default to ``dfs``
       :query string direction: direction in which graph edges will be followed;
           can be either ``forward`` or ``backward``, default to ``forward``
+      :query string return_types: types of nodes we want to be displayed; default to ``"*"``
+
 
       :statuscode 200: success
       :statuscode 400: invalid query string provided
@@ -229,6 +242,7 @@
 -----
 
 .. http:get:: /graph/visit/nodes/:src
+    :query string return_types: types of nodes we want to be displayed; default to ``"*"``
 .. http:get:: /graph/visit/edges/:src
 .. http:get:: /graph/visit/paths/:src
 
@@ -241,6 +255,7 @@
         ``"*"``
     :query string direction: direction in which graph edges will be followed;
         can be either ``forward`` or ``backward``, default to ``forward``
+    :query integer max_edges: how many edges can be traversed during the visit; default to 0 (not restricted)
 
     :statuscode 200: success
     :statuscode 400: invalid query string provided