diff --git a/share/jupyter/voila/templates/base/page.html b/share/jupyter/voila/templates/base/page.html
index 3c09d04b1..1c4bae24b 100644
--- a/share/jupyter/voila/templates/base/page.html
+++ b/share/jupyter/voila/templates/base/page.html
@@ -20,7 +20,7 @@
 
   </head>
 
-  <body data-base-url="{{ base_url }}voila/">
+  <body data-base-url="{{ base_url }}voila/" data-voila="voila">
 
     <noscript>
       <div id='noscript'>
diff --git a/share/jupyter/voila/templates/classic/index.html.j2 b/share/jupyter/voila/templates/classic/index.html.j2
index 7d304ac84..3377c6be9 100644
--- a/share/jupyter/voila/templates/classic/index.html.j2
+++ b/share/jupyter/voila/templates/classic/index.html.j2
@@ -58,7 +58,7 @@
 {%- endblock html_head_js_mathjax -%}
 
 {% block body_header %}
-<body data-base-url="{{resources.base_url}}voila/">
+<body data-base-url="{{resources.base_url}}voila/" data-voila="voila">
   {{ spinner.html() }}
   {{ voila_setup_helper_functions() }}
   <div tabindex="-1" id="notebook" class="border-box-sizing">
diff --git a/share/jupyter/voila/templates/lab/index.html.j2 b/share/jupyter/voila/templates/lab/index.html.j2
index 41e7886c0..1e3df3083 100644
--- a/share/jupyter/voila/templates/lab/index.html.j2
+++ b/share/jupyter/voila/templates/lab/index.html.j2
@@ -59,11 +59,11 @@
 {%- block body_header -%}
 <link rel="icon" href="data:;base64,=">
 {% if resources.theme == 'dark' or resources.theme == 'JupyterLab Dark' %}
-<body class="jp-Notebook theme-dark" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="false" data-jp-theme-name="JupyterLab Dark">
+<body class="jp-Notebook theme-dark" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="false" data-jp-theme-name="JupyterLab Dark" data-voila="voila">
 {% elif resources.theme == 'light' or resources.theme == 'JupyterLab Light' %}
-<body class="jp-Notebook theme-light" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="true" data-jp-theme-name="JupyterLab Light">
+<body class="jp-Notebook theme-light" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="true" data-jp-theme-name="JupyterLab Light" data-voila="voila">
 {% else %}
-<body class="jp-Notebook" data-base-url="{{resources.base_url}}voila/" data-jp-theme-name="{{resources.theme}}">
+<body class="jp-Notebook" data-base-url="{{resources.base_url}}voila/" data-jp-theme-name="{{resources.theme}}" data-voila="voila">
 {% endif %}
 {{ spinner.html() }}
 {{ voila_setup_helper_functions() }}
diff --git a/share/jupyter/voila/templates/reveal/index.html.j2 b/share/jupyter/voila/templates/reveal/index.html.j2
index 8b24d65fb..3207f515d 100644
--- a/share/jupyter/voila/templates/reveal/index.html.j2
+++ b/share/jupyter/voila/templates/reveal/index.html.j2
@@ -64,9 +64,9 @@
 
 {% block body_header %}
 {% if resources.theme == 'dark' %}
-<body class="jp-Notebook" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="false" data-jp-theme-name="JupyterLab Dark">
+<body class="jp-Notebook" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="false" data-jp-theme-name="JupyterLab Dark" data-voila="voila">
 {% else %}
-<body class="jp-Notebook" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="true" data-jp-theme-name="JupyterLab Light">
+<body class="jp-Notebook" data-base-url="{{resources.base_url}}voila/" data-jp-theme-light="true" data-jp-theme-name="JupyterLab Light" data-voila="voila">
 {% endif %}
 {{ spinner.html() }}
 {{ voila_setup_helper_functions() }}
