What is a BSUID on WhatsApp?

The definition in two minutes

BSUID stands for “business-scoped user ID”. Meta creates it automatically for a person who writes to your business. It identifies that person without revealing their phone number.

It exists because a WhatsApp customer can adopt a username, which shows in place of their number. Adoption is optional, for customers and businesses alike. When it happens, your software does not always receive the number any more: it receives the BSUID.

Meta makes support for it mandatory for partners and businesses integrated directly with the WhatsApp Business Platform, and for Click to WhatsApp advertisers. For a small business, the software has to handle it.

What it looks like and how it lives

• Format: the customer’s country code in two letters, a dot, then up to 128 characters, for example “GB.12345678901234567890” (a made-up example). It has to be copied in full: a missing character makes the send fail.
• Scope: a BSUID belongs to your business portfolio. The same customer has a different BSUID with another business. Every WhatsApp number in your portfolio can use it; a number from another portfolio fails.
• Lifespan: Meta regenerates it if the customer changes their phone number, and flags this with a system message. The same customer can therefore have several BSUIDs over time.
• Use: it can be used to send every type of message, except authentication templates of the one-tap, zero-tap and “copy code” kinds, which need the number. According to Meta, sending to a BSUID is supported from July 2026.

When the number is still passed on

So that you do not lose the thread of conversations under way, Meta keeps sending the number of a customer who has adopted a username in three cases:

• you wrote to or called their number in the last 30 days;
• they wrote to or called you from their number in the last 30 days;
• they are in your business’s address book, kept by Meta.

These rules are judged business number by business number. Outside those cases, you receive the BSUID and the username, without the number.

• WhatsApp usernames and BSUIDs: the full guide →

What it means for a small business

• A customer can no longer always be recognised by their number. In your customer file, the BSUID becomes one more key, next to the number.
• A former customer who changes number comes back with a new BSUID: they can look like a new customer. Match the records using their name or email.
• When you need the number (delivery, quote, appointment reminder), ask for it in the conversation and note it in the record. Meta also provides a contact details request button, which the customer taps to share their number, in a template or an interactive message.
• A BSUID points to one specific person: treat it with the same care as a phone number, and respect their consent choices.

WYP.chat receives customers without a number and replies to them in the conversation.

• WhatsApp consent: rules and wording →
• Connect your number with WYP.chat →

Meta’s words

BSUID

Business-scoped user ID. It appears in the “user_id” field of incoming messages.

Username

A unique, optional name that the customer chooses and that shows in place of their number. The field is called “username”.

Business portfolio

The grouping of your accounts at Meta, which Meta used to call Business Manager. The BSUID belongs to that portfolio.

Example

Illustrative case: a bookshop receives a message from a customer who has adopted a username. Their number does not appear, their BSUID does. The bookseller replies in the conversation, asks for a number to say when the book arrives, then notes it on the customer’s record.

Frequently asked questions