To align with Meta’s privacy improvement that allows WhatsApp users to optionally select a username and hide a phone number, we store the username in a new MessagingEndUser object field. Find this new username, known as a Business-Scoped User ID (BSUID), in the MessagingExternalUserKey field. Previously, WhatsApp users were identified by their phone number, which continues to reside in the MessagingPlatformKey field.
Where: This change applies to Enhanced WhatsApp channels. View supported editions.
When: As early as June 2026, businesses can send messages to a user’s BSUID if the user’s phone number isn't available. The rollout date varies by country, so see the WhatsApp documentation for details.