diff --git a/data/apps/helpers.d/user_exists b/data/apps/helpers.d/user_exists
new file mode 100644
index 000000000..662036f55
--- /dev/null
+++ b/data/apps/helpers.d/user_exists
@@ -0,0 +1,3 @@
+ynh_user_exists() {
+    sudo yunohost user list --json | grep -q "\"username\": \"${1}\""
+}
\ No newline at end of file