diff --git a/dev-server/templates/index.mustache b/dev-server/templates/index.mustache
index 4c774d751cf..2180b84eaa9 100644
--- a/dev-server/templates/index.mustache
+++ b/dev-server/templates/index.mustache
@@ -2,6 +2,7 @@
 <html>
 <head>
   <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>Hypothesis Client Test</title>
 <style>
   body {
