Overview

Overview

WhatsApp is rolling out usernames. A user can enable a username and, from that moment on, talk to your business without sharing their phone number.

So that you can keep messaging them, Meta gives you an alternate identifier called a BSUID (business-scoped user ID). A BSUID uniquely identifies that user within your business: the same person has a different BSUID with another company, so it is not usable outside your portfolio.

Why it matters

• The phone number is no longer guaranteed. It can arrive empty both in the messages you receive and in the events we relay to you.
• Supporting BSUID is mandatory for every WhatsApp Business Platform partner and direct integration, and for CTWA advertisers.
• Adopting a username is optional for the end user. You will live with both worlds: contacts with a phone number and contacts without one.

What changes and what does not

Sending a message does not change. The flow is the same, the endpoint is the same and the contract is the same. The only new thing is that the same to field now also accepts a BSUID.

Aspect	Status
Send endpoint	Unchanged
Payload structure	Unchanged — no field was added
to field	Now also accepts a BSUID, in addition to a phone number
from field	Unchanged: still your sender
Message content	Unchanged
Relayed webhook events	Two properties are added: ToBsuid and FromBsuid
SMS and RCS channels	Unchanged: there is no BSUID concept

You do not have to migrate anything or change your integration to keep sending to phone numbers. The change is additive: whatever worked before keeps working exactly the same.

Timeline

Date	What happened
April 2026	Meta starts including the BSUID in message webhooks, even when the user has not enabled a username.
July 2026	Meta enables sending messages to a BSUID through the API.
During 2026	Gradual rollout of usernames across WhatsApp users.

Reference

Official Meta documentation: Business-scoped user IDs

Continue with Recipient Identifiers for the accepted formats and limits.