diff --git a/apps/pwa/vite.config.ts b/apps/pwa/vite.config.ts
index 19f835d..3182c98 100644
--- a/apps/pwa/vite.config.ts
+++ b/apps/pwa/vite.config.ts
@@ -44,6 +44,10 @@ export default defineConfig({
     }),
   ],
   server: {
+    // Allow the internal split-DNS domain (and any subdomain) to reach the dev
+    // server through the reverse proxy / tunnel. A leading dot matches the apex
+    // and all subdomains. Dev-server only — production builds ignore this.
+    allowedHosts: ['.bergerhouse.net'],
     proxy: {
       '/health': 'http://localhost:3000',
       '/api': 'http://localhost:3000',