diff --git a/search-app/server.js b/search-app/server.js
index 3b0da82..9dd4f61 100644
--- a/search-app/server.js
+++ b/search-app/server.js
@@ -123,6 +123,10 @@ const server = http.createServer((req, res) => {
         res.writeHead(200, {
             'Content-Type': 'text/html; charset=utf-8',
             'Cache-Control': 'no-store, no-cache, must-revalidate',
+            // Clear-Site-Data tells the browser itself to drop cookies,
+            // cached responses, local storage, and SW registrations for
+            // this origin — far more thorough than the JS-side caches.delete.
+            'Clear-Site-Data': '"cache", "storage", "executionContexts"',
             'Service-Worker-Allowed': '/'
         });
         res.end(RESET_HTML);