diff --git a/cache.manifest b/cache.manifest
index f13ec3f49..e7a6190e5 100644
--- a/cache.manifest
+++ b/cache.manifest
@@ -3,9 +3,8 @@ CACHE MANIFEST
 
 # Explicitly cached 'master entries'.
 CACHE:
-sim.css
-js/
 data/
+sprites/
 
 # Resources that require the user to be online.
 NETWORK:
diff --git a/index.template.html b/index.template.html
index b50f8c111..9ba20501e 100644
--- a/index.template.html
+++ b/index.template.html
@@ -45,6 +45,7 @@ http://play.pokemonshowdown.com/development
 		<link rel="stylesheet" href="//play.pokemonshowdown.com/style/jquery.slider.min.css?" />
 		<!-- meta name="mobile-web-app-capable" content="yes" / -->
 		<!-- meta name="apple-mobile-web-app-capable" content="yes" / -->
+		<link rel="manifest" href="/manifest.json" />
 		<meta name="robots" content="noindex" />
 		<meta name="google-signin-client_id" content="912270888098-jjnre816lsuhc5clj3vbcn4o2q7p4qvk.apps.googleusercontent.com">
 		<script>
diff --git a/manifest.json b/manifest.json
new file mode 100644
index 000000000..0b8b69e21
--- /dev/null
+++ b/manifest.json
@@ -0,0 +1,23 @@
+{
+  "short_name": "Showdown!",
+  "name": "Pokémon Showdown!",
+  "icons": [
+    {
+      "src": "favicon-16.png",
+      "type": "image/png",
+      "sizes": "16x16"
+    },
+    {
+      "src": "favicon-48.png",
+      "type": "image/png",
+      "sizes": "48x48"
+    },
+    {
+      "src": "favicon-256.png",
+      "type": "image/png",
+      "sizes": "256x256"
+    }
+  ],
+  "start_url": "/?utm_source=homescreen",
+  "display": "standalone"
+}
\ No newline at end of file