WhatsApp’s end-to-end encryption means messages are only readable on sender and receiver devices; neither WhatsApp servers nor third parties can decrypt them. Linked devices, like WhatsApp Web, sync encrypted messages using keys stored locally, not online. Backups can be encrypted if the user enables end-to-end encrypted backups, but these are stored with keys only accessible to the user. Claiming to “view encrypted messages online” without the device or proper access should raise red flags. For legitimate parental monitoring, tools like Eyezy operate by accessing devices directly, not by bypassing encryption remotely.