In brief
- Yes, your customers will be able to write to you on WhatsApp without giving you their number. WhatsApp is rolling out usernames country by country: a customer who adopts one no longer passes their number to the businesses they write to, unless there has been a recent exchange.
- Instead, the business receives a BSUID, an identifier specific to its account. Meta has been sending it since April 2026, and has allowed businesses to message a customer with it since July.
- Anything that recognises a customer by their phone number is affected: customer records, order matching, conversation history, automated flows, measurement of ads that lead to WhatsApp.
- On the business side, it is a brand question: a username is unique across all of WhatsApp. It can be reserved, and once someone else has taken it, it is gone.
With WhatsApp usernames, a customer can write to you without you receiving their phone number: your tool receives a BSUID instead, an identifier that only exists for your business. If your customer file recognises people by their number, it has to learn to recognise them by this identifier too, and it can start now.
Am I affected? Three questions 1. Do your WhatsApp conversations arrive in a tool, customer service software, a CRM, a chatbot, rather than only on a phone? If so, that tool will receive messages without a number. 2. Does that tool find a customer by their phone number? If so, it needs to learn to use the BSUID as well. 3. Is your brand name already the name of your Facebook Page or Instagram account? If not, nothing reserves it for you on WhatsApp.
What is the BSUID on WhatsApp?
The BSUID (business-scoped user ID) is the identifier Meta assigns to each WhatsApp customer for a given business, which lets the business message them without knowing their phone number. It is generated automatically, starts with the customer’s country code followed by a full stop, for example GB. then a string of digits, and it is unique to each business-customer pair: two businesses do not see the same identifier for the same person. It is regenerated if the customer changes number.
Meta has added it to every message received by businesses since April 2026, whether or not the customer has adopted a username, and since July 2026 has allowed businesses to send a message with this identifier rather than a number. In other words, it already reaches your tool today: the question is whether your tool keeps it.
What changes when a customer adopts a username?
The username is optional. A user who picks one sees that name shown instead of their number in the app, and, according to WhatsApp, a person or business they write to for the first time no longer sees their number. They can change username from time to time; this changes neither their number, nor their BSUID, nor their ability to write to businesses.
The number does not disappear everywhere, or immediately. Meta keeps passing on the number of a customer who has adopted a username in three cases: if the same business phone number has messaged or called them in the last 30 days, if it has received a message or call from them in that time, or if the customer is in the contact book Meta keeps for the business.
| Customer’s situation | What your tool receives |
|---|---|
| Has not adopted a username | Their number and their BSUID. The most common case at launch |
| Has adopted a username, and you have exchanged with them from this business number in the last 30 days, or they are in your contact book | Their username, their BSUID and their number |
| Has adopted a username, with no recent exchange and no contact book entry | Their username and their BSUID, without a number |
Which customer is at risk of arriving as a stranger?
The problem case is not the new customer. It is the customer who ordered in spring, talked to your customer service at the time, has since adopted a username, and writes again in November. The 30 days have passed. If she is not in your contact book, her message arrives without a number, with an identifier your tool has never seen. Meta says so in its documentation: such a message may look like one from a new customer.
In practice, your agent sees a stranger. They find neither the order nor the previous exchange, and ask again for a phone number or order number. In the tool, a second record is created next to the first. And the automated flows that start from a customer record, reminders, order tracking, post-purchase reviews, no longer know who to address. Meta is explicit on this point: a business that does not handle the BSUID and receives messages it cannot process has no recourse.
The contact book reduces this risk, with an important limit: it only keeps exchanges that took place after its launch, with no backfill of history. It is hosted by Meta, needs no integration, and can be switched off in the business settings; switching it off deletes what it held, with no way back.
How do you prepare your customer file?
- List everything that uses the phone number as a key. Customer records, matching a conversation to an order, contact deduplication, automated flows, reports, measurement of ads that open a WhatsApp conversation. For each one, note what happens if the number is missing.
- Add the BSUID as a second key, now. It already arrives with messages: store it next to the number on every record. Every customer who writes to you today with their number is a customer you will be able to recognise tomorrow without it. Meta recommends exactly this: handle several identifiers and link them in your customer records.
- Ask your provider, in writing, with the email below.
- Plan to ask for the number when you need it. Meta offers a contact-sharing button, to place in an interactive message or in a utility or marketing template: if the customer taps it, their number is passed to you. Its label cannot be customised and is shown in the customer’s language. Keep it for cases where the number genuinely matters, delivery or a call-back for instance, and plan what happens when the customer declines.
- Check your login codes. The BSUID can be used to send every type of message except three authentication formats: one-tap autofill, zero-tap autofill and copy code. Those require the number. If your customers log in with a code received on WhatsApp, test it.
The email to send your provider, ready to copy
Subject: WhatsApp usernames and BSUID, where do you stand?
Hello,
WhatsApp is rolling out usernames, and since April 2026 Meta has been sending a BSUID identifier (user_id field) with incoming messages. Could you confirm the following three points in writing?
1. Does your tool store each customer’s BSUID on their record, next to their number, as of today?
2. When a message arrives without a phone number, does your tool match it to the customer’s existing record, and how? What happens to a message it cannot match?
3. Does your tool let us send a message to a BSUID, and offer the contact-sharing button in our flows?
Please tell me, for each point, whether it is already in place or by what date it will be.
A ten-minute self-check: open the last five WhatsApp conversations in your tool and see whether the BSUID appears anywhere on the customer’s record. If it appears nowhere, your tool may be receiving it without keeping it.
How do you reserve your brand’s WhatsApp username?
A business reserves its WhatsApp username from WhatsApp Manager, Meta Business Suite or the WhatsApp Business app, open for reservations since 29 June 2026; the name becomes visible when the feature reaches its country. It is above all a brand issue. A name is unique across all of WhatsApp: no two numbers, whether they belong to individuals or businesses, can carry the same one. A name that has already been claimed is refused. There is no directory: a customer finds you by typing your exact username, whereas your business display name cannot be searched.
Meta has reserved for businesses the name of their Facebook Page or Instagram account. To claim it, you have to link your business phone number to that Page or account, with sufficient rights over it. A brand with neither has nothing reserved.
What a username does not do for a business It does not hide your number. Meta says it in so many words: business usernames are not intended for privacy, and your business number remains shown on your profile. In a conversation, WhatsApp first shows the name under which the customer saved you, then your verified business name, and only after that your username.
Three rules for choosing. One name per number, and one number per name: a brand with a sales line and a customer service line will have two separate names. The format is strict: 3 to 35 characters, Latin letters without accents, digits, full stops and underscores, at least one letter, no full stop at the start, at the end or doubled, and no domain ending such as “.com”. Finally, case does not count but full stops and underscores do: “myshop” and “MyShop” are the same name, “my.shop” and “my_shop” are two others. If someone impersonates your brand, Meta provides an impersonation report and an intellectual property form.
What should you do first?
| Option | What it gives you | For whom |
|---|---|---|
| Store the BSUID now, changing nothing else | Every exchange today prepares tomorrow’s recognition. Little work, and it is what will be missed most if it is not done | Everyone, first |
| Match conversations without a number to the right record | No more duplicates or “unknown” customers in customer service. Requires adapting the tool or the CRM | Shops for which WhatsApp is a major service channel |
| Ask for the number with the sharing button | Recovers the number when the customer agrees. Adds a step to the conversation, and some will decline | Cases where the number genuinely matters: delivery, call-back, login |
| Reserve the brand name | A few minutes, and the name can no longer be taken by someone else | All brands, especially those without a Facebook Page or Instagram account in their name |
| Wait for customers to adopt usernames | Nothing breaks at first, then every affected customer arrives as a stranger, with no recourse | Nobody |
How do you know whether your tool is ready?
Four criteria are enough: it stores the BSUID on the customer record, next to the number; it finds an existing record when a conversation arrives without a number; it can send a message to a BSUID, for follow-ups and reminders; and it can offer the contact-sharing button at the right moment in a flow. If you run several business portfolios with Meta, add a fifth: the BSUID changes from one portfolio to another, and Meta offers a shared identifier for this case to eligible businesses, to be requested from your Meta contact.
Method comes before the tool: a ready tool is useless if the customer file itself only keeps the number.
The bigger picture
The phone number has long been the most reliable key in online retail: unique, stable, and given by the customer themselves. WhatsApp turns it into data the customer chooses whether or not to share. Each business now receives an identifier that is only valid with it, which protects the customer and obliges the shop to build its own continuity. It is the same movement as for GDPR in everyday marketing: what you know about a customer, you know because they gave it, and you must be able to prove it.
For a shop, the lesson goes beyond WhatsApp: a customer file that rests on a single identifier depends on the platform that provides it. Having two, and knowing how to link them, is what keeps the relationship standing when one changes its rules. That is the starting point of our marketing automation expertise: workflows that know who they are talking to, before knowing what to say.
Sources
The verifiable statements in this article point to their primary source, opened on 27 September 2026. We do not cite sources we have not read.
- Meta for Developers, “Business-scoped user IDs”, updated 15 September 2026, French and English versions. Read
- WhatsApp, “It’s time to reserve your WhatsApp username”, official blog, 29 June 2026. Read
FAQ
What is the WhatsApp BSUID?
It is the identifier Meta assigns to each WhatsApp customer for a given business, in the form of a country code, a full stop and a string of characters. It lets a business message a customer without knowing their number, it differs from one business to another, and it changes if the customer changes number. Meta has included it in every incoming message since April 2026.
Are WhatsApp usernames already live in my country?
WhatsApp is rolling out usernames country by country and announces in the app when they are available. BSUIDs, on the other hand, have been arriving in messages received by every business since April 2026, and name reservations have been open since 29 June 2026. So there is nothing to wait for before starting.
Does a username hide my business phone number?
No. Meta states that business usernames are not intended for privacy: your business number remains shown on your profile. Only individuals can hide their number with a username.
Can I still send a reminder to a customer who has hidden their number?
Yes, with their BSUID: Meta allows every type of message to be sent to a BSUID, except three authentication formats. The usual rules still apply, the 24-hour window for free-form replies and approved templates outside it. They are set out, with their cost from 1 October, in our article on WhatsApp service messages becoming chargeable.
Is Meta’s contact book enough?
It helps, but it is not enough. It only keeps exchanges after its launch, not history, and it is specific to each business portfolio. It allows Meta to keep passing you the number of a customer who has adopted a username; it does not, for all that, match that customer to their record in your tool. That work remains yours.
Can Dotsland help?
Yes. An inventory of everything that relies on the phone number, adding the BSUID to customer records, matching conversations without a number, and a review of the automated flows that depend on them. It is a workstream of our marketing automation expertise. Let’s talk, or start with the five-conversation self-check.