diff --git a/frontend/index.html b/frontend/index.html
index b4cdc0c..354a812 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -11,7 +11,8 @@
       <link rel="mask-icon" href="/htwk-mask.svg" color="#00494c" />
       <link rel="apple-touch-icon" href="/apple-touch-icon.png" />
       <meta name="theme-color" content="#1b2022">
-      <link
+      <script src="/registerSW.js"></script>
+    <link
       id="theme-link"
       rel="stylesheet"
       href="/themes/lara-light-blue/theme.css"
diff --git a/frontend/src/vite-env.d.ts b/frontend/src/vite-env.d.ts
index 5d1acc1..8fef6df 100644
--- a/frontend/src/vite-env.d.ts
+++ b/frontend/src/vite-env.d.ts
@@ -15,3 +15,5 @@
 //along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 /// <reference types="vite/client" />
+
+declare module 'ical.js';
\ No newline at end of file
diff --git a/frontend/vite.config.ts b/frontend/vite.config.ts
index 0e9baec..85f1c19 100644
--- a/frontend/vite.config.ts
+++ b/frontend/vite.config.ts
@@ -67,7 +67,21 @@ export default defineConfig({
       registerType: 'autoUpdate',
       workbox: {
         globPatterns: ['**/*.{js,css,html,ico,png,svg,json,vue,txt,woff2}'],
-        cleanupOutdatedCaches: true
+        cleanupOutdatedCaches: true,
+        runtimeCaching: [
+          {
+            urlPattern: /^https?.*/,
+            handler: 'NetworkFirst',
+            options: {
+              cacheName: 'https-calls',
+              expiration: {
+                maxEntries: 150,
+                maxAgeSeconds: 30 * 12 * 60 * 60, // 1 month
+              },
+              networkTimeoutSeconds: 10, // fall back to cache if api does not response within 10 seconds
+            },
+          },
+        ],
       },
       devOptions: {
         enabled: true,