diff --git a/src/hooks/useWebSocket.ts b/src/hooks/useWebSocket.ts
index 1630a63..88c9887 100644
--- a/src/hooks/useWebSocket.ts
+++ b/src/hooks/useWebSocket.ts
@@ -19,8 +19,8 @@ interface UseWebSocketOptions {
 export function useWebSocket(options: UseWebSocketOptions = {}) {
   const { accessToken, isAuthenticated } = useAuthStore()
   const wsRef = useRef<WebSocket | null>(null)
-  const reconnectTimeoutRef = useRef<NodeJS.Timeout | null>(null)
-  const pingIntervalRef = useRef<NodeJS.Timeout | null>(null)
+  const reconnectTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const pingIntervalRef = useRef<ReturnType<typeof setInterval> | null>(null)
   const [isConnected, setIsConnected] = useState(false)
   const reconnectAttemptsRef = useRef(0)
   const maxReconnectAttempts = 5
diff --git a/src/types/index.ts b/src/types/index.ts
index 64cb61f..d040af7 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -516,3 +516,22 @@ export interface ManualCheckResponse {
   old_status: string | null
   new_status: string | null
 }
+
+// Ticket notification types
+export interface TicketNotification {
+  id: number
+  ticket_id: number
+  notification_type: string
+  message: string
+  is_read: boolean
+  created_at: string
+}
+
+export interface TicketNotificationList {
+  items: TicketNotification[]
+  total: number
+}
+
+export interface UnreadCountResponse {
+  unread_count: number
+}