diff --git a/src/vizarr.tsx b/src/vizarr.tsx
index cd4070f9..cb8af875 100644
--- a/src/vizarr.tsx
+++ b/src/vizarr.tsx
@@ -14,6 +14,10 @@ function App() {
   const setViewState = useUpdateAtom(viewStateAtom);
 
   async function addImage(config: ImageLayerConfig) {
+    if (config.source === 'pwa') {
+      console.warn('Vizarr launched in experimental PWA mode, looking for data at http://localhost:3000.');
+      config.source = 'http://localhost:3000';
+    }
     const { createSourceData } = await import('./io');
     const id = Math.random().toString(36).slice(2);
     const sourceData = await createSourceData(config);
diff --git a/vite.config.js b/vite.config.js
index 0176ece9..dd76493c 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -9,7 +9,7 @@ const manifest = {
   name: 'vizarr',
   short_name: 'vizarr',
   lang: 'en-US',
-  start_url: '.',
+  start_url: '/?source=pwa',
   display: 'standalone',
   theme_color: '#000000',
   icons: [