On June 29, 2026, Meta announced that WhatsApp is introducing usernames: a unique identifier, in the @yourname format, that anyone can choose so others can contact them without knowing their phone number. The rollout is gradual, country by country, throughout the rest of 2026.
When someone activates their username, their phone number is automatically hidden. Your business stops receiving that data when talking to them and instead sees an alternative identifier: the BSUID (Business-Scoped User ID).
Note: usernames are activated by the WhatsApp user, not by your business. You don't decide whether a contact activates one, or when. The only thing within your control is that your platform is ready to keep identifying and replying to that contact — and that's already handled in Darwin.
What changes with usernames
1. Users can hide their phone number
Anyone on WhatsApp can reserve a username of 3 to 35 characters, with at least one letter, using only lowercase letters, numbers, periods, and underscores.
It can't start with "www." or end in domains like ".com" or ".net".
Each person has a single username, but can change it at any time.
The change is one-directional: it gives privacy to the user in relation to the business, not the other way around. Your business number remains visible at all times.
2. Your business sees a BSUID instead of the number
When a contact hides their number, your platform stops receiving the phone number in that conversation and sees a BSUID instead: a unique identifier that Meta assigns to that user for your business. It isn't global — it belongs to your account.
Format: two-letter country code + period + an alphanumeric identifier.
Example: CO.13815218…
The conversation works normally: the contact writes to you and you reply as always. Only the value you see in place of the phone number changes.
3. Campaigns still require a phone number
WhatsApp campaigns and follow-ups sent after the 24-hour window closes need the contact's phone number. While a contact has their number hidden, you can't send them either: they appear disabled in the campaign builder, with a notice.
Authentication templates (one-tap, zero-tap, copy-code) also still require a phone number.
Concept | Before | Now (rollout in progress) |
Contact identifier | Phone number | Phone number, or BSUID if the contact hid their number |
Conversation (replying to messages) | By phone number | Works the same: by phone number or BSUID, handled by Darwin |
Campaigns and post-24h follow-ups | Sent by phone number | Require a phone number: contacts with a hidden number are disabled, unless they share it through official means |
Authentication templates (OTP) | Require a phone number | No change: they require a phone number |
Visibility of your business number | Always visible | No change: always visible |
Note: activating a username does not retroactively hide the number in conversations that already existed. The change applies from that point onward, mainly in new conversations. It does apply from the moment of hiding when you need to message the contact outside the 24-hour window.
Key dates
Date | What happens |
April 2026 | The BSUID starts appearing progressively in webhooks. |
June 29, 2026 | Meta announces the feature and opens username reservation. Reserving doesn't mean it's active yet. |
July 7, 2026 | First country enabled, outside Latin America. |
July 20, 2026 | Second wave: Colombia and Peru, and within the same weeks, the Dominican Republic. |
September 2026 (estimated) | General rollout, which would include Argentina, Mexico, and Brazil. |
Meta hasn't published a country-by-country schedule, so the general rollout date may shift. On our side, we're working with September 1 as the reference point.
What stays the same
Your business number. Hiding is exclusive to personal accounts: your business line's number is never hidden.
Your current database. WhatsApp keeps a per-business contact book, managed by Meta, where any contact you've exchanged messages or calls with is recorded with both their phone number and their BSUID. Because of this, if an existing contact activates their username, you keep receiving their number as long as the relationship is active (Meta guarantees this when there's been interaction in the last 30 days). For contacts with no recent activity, the number may stop arriving and you'll see the BSUID instead.
Conversations. Conversations work as always, whether the contact's number is visible or hidden.
What Darwin does
1. Identifies the contact even without a phone number
When a contact has no phone number available, Darwin uses their BSUID as an alternative identity and the conversation continues with no action needed on your side. Flows that use the phone number as the primary identity remain intact.
2. Asks the contact for their number, automatically
Since any communication outside the 24-hour window requires a phone number, Darwin handles the capture inside the conversation itself: when a contact with a hidden number moves forward in the conversation, the worker automatically sends a message with a button to share their number in a single tap. This is an official Meta mechanism.
It applies to all workers.
It's sent once per session and within the 24-hour window.
It's configurable per channel and per stage.
If the contact shares their number, you regain campaigns, follow-ups after the window closes, and any flow that depends on the phone number. According to Meta, the number stays available for campaigns for at least 30 days from the moment the contact shares it.
Frequently asked questions
Can I send campaigns to a contact who hid their number? Not until you have their phone number: they'll appear disabled in the campaign builder. Darwin asks for the number automatically as the conversation progresses, and once they share it, you can include them again.
Does a username replace the phone number as the contact's identity? No. People can change their username whenever they want, so it isn't a stable identifier. The identity is still the phone number when available, or the BSUID when it isn't.
Can I ask a contact for their username to identify them? There's no need. The username is a display value that's always available, not an identity key.
Does this apply to all countries at the same time? No. The rollout is gradual: it started on July 7, 2026 outside Latin America, continued with Colombia, Peru, and the Dominican Republic, and the general rollout — which would include Argentina, Mexico, and Brazil — is expected in September 2026.
Where can I verify the official information? In Meta for Developers' Business-Scoped User IDs documentation, the only authoritative source: https://developers.facebook.com/documentation/business-messaging/whatsapp/business-scoped-user-ids/