A customer messages your business on WhatsApp. Your CRM looks them up by phone number, matches them to their order history, and your agent replies with full context. That workflow has powered WhatsApp business messaging for years. In 2026, it quietly started breaking.
The reason is usernames. When a customer adopts a WhatsApp username, their phone number can vanish from your webhook payloads entirely. If your systems identify people only by phone number, you'll suddenly receive messages from customers your CRM can't recognize. New tickets, lost history, broken automations. It ties directly into WhatsApp's username key privacy model.
Meta's answer is a new identifier called BSUID, and it's already flowing into your webhooks whether you've prepared or not. This guide explains exactly what BSUID means, how it changes your API and CRM, and the concrete steps to stay ready. If you run WhatsApp Business messaging at any scale, this isn't optional reading.
The New WhatsApp Username Feature Explained
WhatsApp usernames let people message businesses without sharing their phone number. Announced in June 2026 and rolling out in phases, the feature is optional for users and businesses alike. For businesses, the important part isn't the username itself. It's the new backend identifier Meta introduced to keep your messaging working when phone numbers disappear.
How WhatsApp Usernames Work
A user claims a handle and shares it instead of their number. When they message your business, they can keep their phone number hidden. Your business still receives and replies to the conversation, but the identifier attached to that customer changes underneath.
Why WhatsApp Is Introducing Usernames
For years, messaging anyone on WhatsApp meant exposing a phone number. Usernames give three billion users control over their most personal identifier. For businesses, this is a privacy shift you don't control but must accommodate, because customers will increasingly hide their numbers from you.
What Is BSUID in WhatsApp Business?
BSUID stands for Business-Scoped User ID. It's a unique identifier Meta generates for every user-and-business pair, so you can recognize and message a customer even when their phone number is hidden. It appears in all message webhooks, whether or not the customer has adopted a username, which makes it your new durable identity key.
BSUID Explained
Think of a BSUID as a private membership number your business uses to recognize a specific WhatsApp user. It's not a universal internet identity. The same customer has a completely different BSUID with every business they contact, and yours only works within your own portfolio.
How BSUID Is Generated
Meta generates the BSUID automatically, one per business-portfolio-and-user pair. The format is an ISO two-letter country code, a period, then up to 128 alphanumeric characters. To tell a BSUID apart from a phone number, check whether the value starts with two letters followed by a period.
BSUID vs WhatsApp Phone Number
A phone number is in E.164 format and can be used to message anyone. A BSUID is portfolio-scoped and only works from your business. A BSUID also stays stable unless the customer changes their phone number, in which case Meta regenerates it and sends a user_id_update webhook with the old and new values so you can update your records.
BSUID vs External User ID
This trips people up. They're the same value with different names. In Meta's Cloud API, the BSUID lands in the user_id field. Some providers rename it, so Twilio exposes it as ExternalUserId. If you use a provider, store whatever field they use, but know it's the same underlying BSUID.
Why BSUID Matters for Businesses
BSUID matters because it's becoming the stable key that keeps your customer identification working. Ignore it, and username-adopting customers will arrive as unrecognizable strangers, breaking your CRM matching, your automations, and your reporting. Handle it, and your messaging stays seamless through the transition.
Better Customer Privacy
Customers can hide their number while still reaching you. Supporting this smoothly shows respect for privacy.
Reliable Identification
Anchor customer records securely even when the phone number is kept hidden.
Clean CRM Data
Avoid duplicate customer creation and fragmented ticket history in major support setups.
Future-Proofing
Prepare for a platform where phone-number visibility is an exception, not the rule.
How WhatsApp Usernames Change Business Messaging
The core change is simple to state. Phone numbers stop being guaranteed. Everything else follows from that. Here's what shifts for each side and what stays put.
What Changes for Customers
Customers can now message your business without revealing their phone number. They appear by username and profile name, and they control whether you ever see their digits. For them, it's a friction-free privacy upgrade that requires no effort on your part.
What Changes for Businesses
You may receive inbound messages with no phone number, only a BSUID. Your systems must read and store that BSUID, match it to existing records, and be able to send replies addressed to it. Any code assuming the from field is always a phone number needs updating.
What Stays the Same
Reassuringly, a lot. Message templates, message types like text, images, and documents, and the overall structure of the messaging API stay largely consistent. If you already hold a customer's phone number from a prior interaction, you can keep messaging it as before. The change targets username-adopting users specifically.
How BSUID Works with the WhatsApp Business API
At the API level, BSUID arrives as a new user_id field in your webhook payloads. It appears in every message webhook, even for users without usernames, so it's populated and ready to store today. The behavior of the older wa_id and from fields is what changes conditionally.
{
"messages": [{
"from": "15550123456", // Still phone number
"id": "wamid.HBgL...",
"type": "text",
"text": { "body": "Hi" }
}],
"contacts": [{
"profile": { "name": "Alex" },
"user_id": "US.1349120865530..." // New: BSUID is here
"wa_id": "15550123456" // Still phone number
}]
}{
"messages": [{
"from": "US.1349120865530..." // changed to BSUID!
"id": "wamid.HBgL...",
"type": "text",
"text": { "body": "Hi" }
}],
"contacts": [{
"profile": { "name": "Alex" },
"user_id": "US.1349120865530...", // BSUID is here
"wa_id": "US.1349120865530..." // changed to BSUID!
}]
}Webhook Changes
For a user without a username, wa_id and from still carry their phone number, and user_id carries the BSUID. For a user with a username, wa_id and from carry the BSUID and no phone number appears. Status webhooks also include the BSUID in a recipient_user_id field.
Handling Messages Without Phone Numbers
When no phone number is present, use the BSUID as the recipient identifier to reply. A helpful cushion exists: Meta's contact book feature returns a customer's phone number for a rolling 30 days after any phone-based interaction. Treat that as a convenience, not a crutch, since it's conditional and portfolio-scoped.
Migration Timeline
How to Prepare Your Business for BSUID
Preparation is mostly a clean identity upgrade, not a rebuild. The safest model is to keep phone numbers wherever you have them, but stop depending on them as your only identifier. Do these four things and you'll ride out the rollout smoothly.
WhatsApp Business Usernames Explained
Businesses can adopt usernames too, but they work differently from personal ones. This distinction matters and is widely misunderstood, so let's be precise about it.
Can Businesses Have Usernames?
Yes. Each business phone number can have one username, and it's unique across WhatsApp. But unlike a personal username, a business username does not hide your phone number. Your business number still shows on your profile. A business username is a display and discoverability feature, not a privacy one.
Username Best Practices for Brands
Match your handle to your brand name and keep it consistent with your Instagram and Facebook presence. Reserve early, because the same handle can be contested across Meta's platforms. Follow the format rules, 3 to 35 characters, lowercase letters, numbers, periods, and underscores, and avoid anything that could read as impersonating another brand.
Common Challenges Businesses May Face
The transition isn't hard, but a few predictable problems catch teams off guard. Anticipate these and you'll avoid the messy fixes later.
Existing Customer Records
Records created before the migration won't have BSUIDs retroactively.
Duplicate Contacts
A username-adopting customer arrives with no phone number, creating a brand new contact.
Authentication & OTP
BSUID cannot be used for authentication template messages (OTPs/One-Tap).
Frequently Asked Questions
BSUID stands for Business-Scoped User ID. It's a unique identifier Meta generates for each business-and-user pair, letting you recognize and message a WhatsApp customer even when their phone number is hidden behind a username. It appears in all message webhooks in the user_id field.
No, not entirely. BSUID becomes your durable identity key, but phone numbers still matter, especially for authentication templates that BSUID cannot use. Store BSUID as primary while preserving numbers where available.
Yes, for standard messaging once API support is fully active. You can reply and re-engage using the BSUID. One-time passcodes and auth templates will still require a phone number.
Yes. If you use the WhatsApp Business API you must handle BSUID logic. If you use a third-party CRM provider, confirm with them if they have managed the transition on your behalf.
Final Thoughts
BSUID is one of the most significant behind-the-scenes changes to WhatsApp business messaging in years, and it's easy to underestimate because it's invisible to customers. The headline is simple: phone numbers are no longer guaranteed, and user_id is your new durable key. If your CRM, chatbots, or automations are keyed only by phone number, treat this as a migration project, not a config tweak.
The good news is the work is contained. Store the BSUID, adopt dual-key matching with write-back, keep phone numbers where you have them, and audit your reporting and OTP flows. Do that now, while BSUID is already flowing but adoption is still ramping, and the global rollout becomes a non-event for you. Is your WhatsApp stack ready to recognize a customer who no longer shows you their number? To get more details on business features, see the full WhatsApp username guide, or read our related articles on the WhatsApp username key, who can find you by username, and WhatsApp username ideas.