diff --git a/api/g3doc/index.md b/api/g3doc/index.md
new file mode 100644
index 0000000000..fe8d9b5582
--- /dev/null
+++ b/api/g3doc/index.md
@@ -0,0 +1,13 @@
+<?% config.freshness.owner = 'hta' %?>
+<?% config.freshness.reviewed = '2021-04-12' %?>
+
+# The WebRTC API
+
+The public API of the WebRTC library consists of the api/ directory and
+its subdirectories. No other files should be depended on by webrtc users.
+
+Before starting to code against the API, it is important to understand
+some basic concepts, such as:
+
+* Memory management, including webrtc's reference counted objects
+* [Thread management](threading_design.md)
diff --git a/api/DESIGN.md b/api/g3doc/threading_design.md
similarity index 94%
rename from api/DESIGN.md
rename to api/g3doc/threading_design.md
index 0a2f36eb2b..868c433abc 100644
--- a/api/DESIGN.md
+++ b/api/g3doc/threading_design.md
@@ -1,4 +1,6 @@
-# Design considerations
+<?% config.freshness.owner = 'hta' %?>
+<?% config.freshness.reviewed = '2021-04-12' %?>
+# API Threading Design considerations
 
 The header files in this directory form the API to the WebRTC library
 that is intended for client applications' use.
@@ -30,7 +32,7 @@ the two calls.
 sequential execution - other names for such constructs are task runners
 and sequenced task queues.
 
-# Client threads and callbacks
+## Client threads and callbacks
 
 At the moment, the API does not give any guarantee on which thread* the
 callbacks and events are called on. So it's best to write all callback
@@ -47,7 +49,7 @@ void ObserverClass::Handler(event) {
 In the future, the implementation may change to always call the callbacks
 and event handlers on the client thread.
 
-# Implementation considerations
+## Implementation considerations
 
 The C++ classes that are part of the public API are also used to derive
 classes that form part of the implementation.
diff --git a/g3doc/sitemap.md b/g3doc/sitemap.md
index 10034d5343..78f11f60dc 100644
--- a/g3doc/sitemap.md
+++ b/g3doc/sitemap.md
@@ -2,7 +2,8 @@
 *   How to contribute
     *   Code
     *   [Documentation](/g3doc/how_to_write_documentation.md)
-*   Public C++ API
+*  [Public C++ API](/api/g3doc/index.md)
+    *   [Threading](/api/g3doc/threading_design.md) 
 *   Implementation
     *   Network
     *   Congestion control and bandwidth estimation