diff --git a/specification/index.rst b/specification/index.rst
index 4cbb1de3..bb918739 100644
--- a/specification/index.rst
+++ b/specification/index.rst
@@ -43,6 +43,8 @@ The specification consists of the following parts:
 The `Appendices <appendices.html>`_ contain supplemental information not specific to
 one of the above APIs.
 
+The `Matrix Client-Server API Swagger Viewer <https://matrix.org/docs/api/client-server/>`_ is useful for browsing the Client-Server API.
+
 Introduction to the Matrix APIs
 -------------------------------
 .. WARNING::