diff --git a/packages/fullstack-server/src/server.rs b/packages/fullstack-server/src/server.rs
index a8a1678ef8..925f61ca2e 100644
--- a/packages/fullstack-server/src/server.rs
+++ b/packages/fullstack-server/src/server.rs
@@ -407,7 +407,7 @@ fn serve_dir_cached<S>(mut router: Router<S>, public_path: &Path, directory: &Pa
 where
     S: Send + Sync + Clone + 'static,
 {
-    use tower_http::services::ServeFile;
+    use tower_http::services::{ServeDir, ServeFile};
 
     let dir = std::fs::read_dir(directory)
         .unwrap_or_else(|e| panic!("Couldn't read public directory at {:?}: {}", &directory, e));
@@ -430,7 +430,19 @@ where
         );
 
         if path.is_dir() {
-            router = serve_dir_cached(router, public_path, &path);
+            // In debug builds, serve directories dynamically so new files (like
+            // wasm patch modules) are immediately visible without rebuilding
+            // the router. In release, keep the previous cached traversal
+            // behaviour.
+            #[cfg(debug_assertions)]
+            {
+                router = router.nest_service(&route, ServeDir::new(&path));
+            }
+
+            #[cfg(not(debug_assertions))]
+            {
+                router = serve_dir_cached(router, public_path, &path);
+            }
         } else {
             let serve_file = ServeFile::new(&path).precompressed_br();
             // All cached assets are served at the root of the asset directory. If we know an asset