diff --git a/index.html b/index.html
index e2bbe04a..03454616 100644
--- a/index.html
+++ b/index.html
@@ -9,6 +9,7 @@
 	content="StackEdit is a free, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.">
 <meta name="author" content="Benoit Schweblin">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta name="msvalidate.01" content="5E47EE6F67B069C17E3CDD418351A612" />
 <script>
 	// http://.../?debug to serve original CSS/JavaScript files for debug
 	var dep = "main-min";
diff --git a/viewer.html b/viewer.html
index b74e46b9..053a723a 100644
--- a/viewer.html
+++ b/viewer.html
@@ -9,6 +9,7 @@
 	content="StackEdit is a free, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.">
 <meta name="author" content="Benoit Schweblin">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta name="msvalidate.01" content="5E47EE6F67B069C17E3CDD418351A612" />
 <script>
 	// http://.../?debug to serve original CSS/JavaScript files for debug
 	var dep = "main-min";