Where is a client's customer data being stored?

Clients are responsible for storing their own customer contacts and messages. WhatsApp does not store this data for any longer than necessary to route and deliver messages. If a message cannot be delivered immediately, we may keep it on our servers for up to 30 days as we try to deliver it. If a message is still undelivered after 30 days, we delete it. To improve performance and deliver media messages more efficiently, we may retain them on our servers for a longer period of time.