diff --git a/simple_web/explanation.md b/simple_web/explanation.md
index fc34052..0ab150f 100644
--- a/simple_web/explanation.md
+++ b/simple_web/explanation.md
@@ -5,6 +5,13 @@ AsyncWebServer server(80);
 ```
 Start the Web Server on port 80
 
+```
+void notFound(AsyncWebServerRequest *request) {
+    request->send(404, "text/plain", "Not found");
+}
+```
+This will handle requests on wrong uri's with this code `server.onNotFound(notFound);`
+
 ```
 WiFi.begin(ssid, password);
   if (WiFi.waitForConnectResult() != WL_CONNECTED) {