diff --git a/Makefile b/Makefile
index ea1d951..e779e94 100644
--- a/Makefile
+++ b/Makefile
@@ -147,6 +147,12 @@ build-web:
 build-webapp: build-php
 	component=webapp make build
 
+# replaces the actual kopano_webapp container with one that has login hints for demo.kopano.com
+build-webapp-demo:
+	docker build \
+		-f webapp/Dockerfile.demo \
+		-t $(docker_repo)/kopano_webapp webapp/
+
 build-zpush:
 	component=zpush make build
 
diff --git a/webapp/Dockerfile.demo b/webapp/Dockerfile.demo
new file mode 100644
index 0000000..28f6a11
--- /dev/null
+++ b/webapp/Dockerfile.demo
@@ -0,0 +1,5 @@
+ARG docker_repo=zokradonh
+FROM ${docker_repo}/kopano_webapp
+
+RUN sed -i '1s/^/<?php  $user="user".rand(1, 15); ?>\n/' /usr/share/kopano-webapp/server/includes/templates/login.php && \
+    sed -i 's/id="password"/id="password" value="<?php echo $user; ?>"/' /usr/share/kopano-webapp/server/includes/templates/login.php