WhatsApp usernames and BSUIDs: what changes for businesses
WhatsApp now lets people choose a username that shows instead of their phone number. Alongside it, Meta added a new identifier for each customer, the BSUID, which you can message even when you don't know their number. This guide summarises Meta's official documentation: what it means for your business, when you won't receive a phone number, and how to prepare.
Three new concepts
Format: a two-letter country code, a period, then up to 128 alphanumeric characters. Meta's example is US.13491208655302741918. Always use it in full, country code and period included.
When the changes started
| Date | What happened |
|---|---|
| April 2026 | Meta began sending BSUIDs in webhooks |
| June 29, 2026 | Businesses can start reserving usernames |
| July 2026 | APIs support messaging to BSUIDs |
| During 2026 | Usernames roll out gradually to users |
Meta notes that all of these changes are subject to change.
When you won't receive the customer's phone number
If a customer has adopted a username, their phone number is left out of webhooks unless one of these applies:
- You messaged or called their number in the last 30 days.
- They messaged or called you from their number in the last 30 days.
- The customer is in your contact book.
These conditions are evaluated per business phone number, not per portfolio. Customers without a username keep sending their phone number as before, now with a BSUID alongside it.
The contact book and the request-contact button
Contact book: a Meta-hosted feature that needs no integration. It stores the customer's phone number and BSUID once you exchange a message or call from their number, scoped to your portfolio. It's what keeps phone numbers in your webhooks even for customers with usernames.
- It only records interactions after launch. Older contacts aren't added retroactively.
- You can turn it off in Business Settings, but that deletes the stored data, and turning it back on doesn't restore it.
Request contact info button: add it to utility and marketing templates, or send it as an interactive message. When the customer taps it, their number is shared with you and a contacts webhook fires. With the contact book on, the number is saved automatically.
What changes when you send messages
- You can send to a phone number, a BSUID, or both. When both are present, the phone number wins.
- Authentication templates (one-tap, zero-tap and copy code) require a phone number and don't work with BSUIDs. Trying returns error
131062. - The Marketing Messages API supports both, and Meta recommends sending to phone numbers so you keep receiving numbers in webhooks.
- A BSUID belongs to your portfolio. Numbers in another portfolio can't message it unless you use a parent BSUID.
Business username rules
- 3 to 35 characters: English letters, digits, periods and underscores only.
- At least one letter. It can't start or end with a period, or contain two periods in a row.
- It can't start with
www.or end with a domain suffix such as.com. - Case is ignored, but periods and underscores count.
- If the name is already used on a Facebook Page or Instagram account linked to your business, link the business number to that account first.
- Claiming a username requires a sufficiently high messaging limit.
You can claim the reserved name or choose your own in WhatsApp Manager, Meta Business Suite or the Username API. In chats, the app shows a saved contact name first, then a verified business name, then the username, and the phone number last.
How to prepare your business
Test now
Use the webhook test tool in your App Dashboard. It covers cases with and without usernames, and with and without phone numbers.
Store the full BSUID
Keep it as a customer identifier. Don't split off or change the country code.
Don't rely on the phone number alone
Make your systems handle webhooks without a phone number, and key customer records on the BSUID.
Track number changes
System messages tell you when a customer changes their number or their BSUID changes, and include the previous BSUID so you can link the two records.
Ask for the number when you need it
Use the request contact info button when you genuinely need the number, for example for verification or invoices.
Autorply gets you set up
As an official Meta Business Partner, we connect your channels, prepare your accounts and run them with your team from one platform.
FAQ
Does a username hide my business phone number?
No. According to Meta, business usernames are optional and don't hide the business number.
Can I send an authentication code to a customer whose number I don't know?
No. Authentication templates require a phone number. Sending one to a BSUID returns error 131062.
What happens when a customer changes their phone number?
They get a new BSUID, and you receive a system message with both the old and new BSUID so you can link them.
Does the contact book need any development work?
No. Meta hosts it with no integration needed, and you can turn it off in Business Settings.