diff --git a/api/api.go b/api/api.go
index 916af47..1065aa5 100644
--- a/api/api.go
+++ b/api/api.go
@@ -74,14 +74,19 @@ func SetupApiServer(listen string, auth *AuthChecker, send Smtp, recv Imap) *htt
 			return
 		}
 
-		_ = authUser
-
+		// open imap client
 		client, err := recv.MakeClient(authUser.Subject)
 		if err != nil {
 			_ = c.WriteJSON(map[string]string{"error": "Making client failed"})
 			return
 		}
 
+		// auth was ok
+		err = c.WriteJSON(map[string]string{"auth": "ok"})
+		if err != nil {
+			return
+		}
+
 		for {
 			// authenticated users get longer to reply
 			// a simple ping/pong setup bypasses this