Azure Communication Services: WhatsApp BSUID Support
Microsoft Azure Communication Services (ACS) is updating its Advanced Messaging APIs to support WhatsApp Business Scoped User IDs (BSUIDs). If you use ACS for WhatsApp messaging, your EventGrid webhook handlers must be updated to process the new BSUID schema.
What Is Changing in ACS
Azure ACS passes WhatsApp Cloud API payloads through EventGrid events. With the introduction of BSUIDs, the from field in inbound message events will contain a scoped identifier instead of a phone number when users contact you via a WhatsApp username.
EventGrid Payload Changes
The data.from field in your ACS EventGrid webhook will now carry BSUID strings. Your event handler must detect and process these identifiers correctly.
Migration Guide for Azure Customers
- Update your EventGrid event handler to accept string-based
fromvalues - Add BSUID storage to your Azure SQL or Cosmos DB contact records
- Implement dual-format parsing logic that detects BSUID vs phone number format
- Update your Azure Functions or Logic Apps that process WhatsApp messages
- Test your updated handler using ACS's EventGrid delivery testing tools
Dual-Mode Period
ACS will support both phone numbers and BSUIDs during Q3 2026. After Q4 2026, new username-initiated conversations will exclusively carry BSUID identifiers. Existing conversations retain their legacy wa_id format.
Need Help?
Use the RezervSpot BSUID Audit Tool to validate your webhook endpoint handles BSUID payloads correctly before the production rollout.