Guide · Customer records · For the owner whose list is phone numbers

When a WhatsApp customer's phone number stops arriving: usernames, customers from your Facebook or Instagram ads, the 30-day rule, the contact book and the Share Contact Info button

Most businesses treat a WhatsApp customer and a phone number as the same thing: the number is the record, the search key and the thing the sales team calls. WhatsApp usernames change that. Once a customer adopts one, Meta may stop passing their phone number to the system connected to your business number. Meta's page explains when the number is still shared, what identifies the customer instead, and the two tools, a button and a contact book, that let a business keep the numbers it needs. WhatsApp's Help Center adds a second case every business running ads should know: a customer who reaches you from a Facebook or Instagram ad can arrive with their number hidden. Here is the owner's version.

Published 1 October 2026 · Updated 15 October 2026

What changes when a customer adopts a username

Meta's developer page (updated 15 September 2026) said usernames would roll out gradually in 2026, and WhatsApp's Help Center still described them as rolling out when we read it on 15 October 2026. Adopting one is optional for the customer. A customer who does is shown by username instead of phone number in the app, and Meta's page says their phone number is then withheld from the system behind your business number unless one of three conditions holds: your business number messaged or called them in the last 30 days, they messaged or called your business number in the last 30 days, or they are in your contact book. The 30-day look-back is counted per business number, so a customer who dealt with your sales number last week is still a stranger to your support number.

In every case, including customers with no username, Meta now identifies the person by a code it issues for your business, which it calls a business-scoped user ID. The code is unique to the pair of your business portfolio and that customer, is the same across all the numbers in your portfolio, and is different from the code any other business holds for the same person. A customer who changes their phone number gets a new code too. Your system can send to the code exactly as it would to a number, with one exception Meta names: the one-tap, zero-tap and copy-code styles of login-code template still need the phone number.

Why your provider has to support this

Meta says supporting the code is required of every system connected to a business number, because the business cannot control which customers adopt usernames. A system that still files everything under the phone number will, for those customers, receive messages it cannot attach to a record, and may be unable to reply. The business-side of usernames, including how to reserve your own name, is in the business username guide.

Customers who reach you from a Facebook or Instagram ad

WhatsApp's Help Center article About phone number hiding says a customer can start a WhatsApp chat with a business straight from an ad on Facebook or Instagram, and that in some cases, the first time they open a chat with a business, their phone number is hidden from that business by default. The business then can't see the number or call it unless the customer chooses to share it, and the customer sees a system message in the chat saying so.

The customer can share it in one of two ways: from the business's name or number in the chat, then Phone number privacy, then SHARE NUMBER, or, if the business has asked for it, by tapping Share phone number, then SHARE NUMBER. Two limits apply. A customer can't hide their number from a business that already has it from an earlier interaction, and once they share it they can't turn sharing off again.

The article About sharing your phone number with businesses covers customers who already have a username: if they have one in place the first time they chat with a business, their number is kept private, but their country is shared, based on the number's country code. It says a business may ask for the number to help process an order or payment, and the customer can answer with a contact card showing their phone number, their username or both, or simply type the number into the chat.

What Meta receives when the chat starts from an ad: WhatsApp's article About WhatsApp chats that start from ads on Meta says that if the customer opens the chat within seven days of interacting with the ad, Meta, WhatsApp's parent company, receives limited information, to improve its ads and help detect potential scams. WhatsApp does not share the content of messages or calls, or the customer's name or phone number. Meta may receive things like feedback the customer submits, how many chats and calls they have with the business, when they browse its products and services or use its ordering information and links, and how long a browser stayed open on a link the business shared. An icon marks this; the customer can tap it to learn more or decide not to chat with the business, in which case no information is shared.
A customer who finds you by username: WhatsApp's article How to contact someone by username (in the general Usernames section; WhatsApp has separate pages for business usernames) says a person can message or call someone with their exact username, plus a username key if one is set. The chat shows the username and display name, and the phone number only if it is already saved. No key is needed if the number is already saved, the two have chatted before, they share a group, the QR code was scanned, or the other person messaged first. Our reading: the same steps apply when a customer looks up a business username.

Our reading

A lead from an ad with no number attached looks like the same gap as a customer with a username. Asking with the Share Contact Info button, in the next section, is the business's side of it. The contact book can only keep a number the customer has actually shared; it does not reveal a hidden one. Ask for the number where WhatsApp's own article says a business may need it, at the order or payment step, rather than in the first reply. And because the customer wrote first, you don't need their username key to answer.

Two tools for keeping the numbers you need

The Share Contact Info button: Since early July 2026 a template or an interactive message can carry a button that asks the customer to share their phone number. Meta says it goes on utility and marketing templates, its label cannot be changed and is shown in the customer's own language, and when tapped it delivers the number to your system. A customer who instead attaches a contact card from the app also delivers it, with the card.
The contact book: A store Meta hosts for your business portfolio, with no setup required. After any message or call in either direction, the customer's phone number and code are recorded, and from then on the number is passed to your system whether or not the customer uses a username. It is not retroactive: only interactions after the feature becomes available are recorded.

The contact book can be switched off in Meta Business Suite, under Business settings, then Business info. Meta's page is clear about the consequence: switching it off deletes what it holds, and switching it back on later does not bring that data back. An owner who turns it off for privacy reasons should understand that the cost is paid in lost numbers, not in lost messages.

What this means for your customer records

The practical shift is that the phone number becomes one field on a customer record rather than the record itself. A system built for this stores Meta's code as the key, keeps the number when it has it, asks for it with the button when it matters, say before a delivery or a call, and never treats a missing number as a missing customer. Meta's own privacy rules on what it keeps and for how long are in the privacy guide.

For a business that imports customer lists from elsewhere, the other direction still works: Meta's page says a number can be messaged as before, with the usual permission rules in the opt-in guide. Once that customer replies, your system receives their code and, through the contact book, keeps their number.

BitByteCore is a verified Meta Tech Provider (since 9 September 2026). This guide repeats Meta's developer page and WhatsApp's Help Center as we read them, and is not legal advice.

Questions

A new customer wrote to us and our system shows no phone number. Is the message real?

Yes. Usually the customer has adopted a username and had no interaction with that business number in the last 30 days, so Meta withheld the number and passed its code instead. A customer who opened the chat from a Facebook or Instagram ad may also have their number hidden until they choose to share it. Reply as normal; if you need the number, send the Share Contact Info button.

Can we just ask them to type their number?

You can, but the button is better: it delivers the number to your system in a form it can file automatically, and Meta's page says it adds the number to your contact book at the same time.

We have two numbers, sales and support. Why does support not see a number that sales has?

The 30-day look-back is counted per business number. The contact book, however, is shared across the whole portfolio, so once the feature records the customer from either number, both numbers receive it.

Does any of this change what the customer sees?

Only that people with usernames see each other by username. Your business number is always shown on your profile; a business username does not hide it.

A customer came from our Instagram ad and the chat shows no phone number. Did the ad break?

Most likely not. WhatsApp's Help Center says customers can start chats from Facebook and Instagram ads, and that in some cases, the first time a customer opens a chat with a business, their number is hidden by default for their privacy. The business can't see or call it until they share it, and the customer sees a message in the chat saying so. A customer with a username can also arrive without a number (see above).

Can we get the number later?

Yes, if the customer chooses to share it, from your business's name in the chat or by answering your request for it. WhatsApp says that once a customer shares their number with a business, they can't turn sharing off again. And if you already had the number from an earlier interaction, it was never hidden from you.

Sources

Meta's developer documentation: Business-scoped user IDs and usernames, read 1 October 2026.
WhatsApp Help Center: About phone number hiding, read 15 October 2026.
WhatsApp Help Center: About sharing your phone number with businesses, read 15 October 2026.
WhatsApp Help Center: About WhatsApp chats that start from ads on Meta, read 15 October 2026.
WhatsApp Help Center: How to contact someone by username, read 15 October 2026.

More plain-language notes like this one are on the guides page.

Want customer records that survive a missing phone number?

We set up a business's WhatsApp number on a proper system that files each customer under Meta's code, keeps the phone number when it is shared, and asks for it with the button when the business needs it, so no message arrives without a record to land in. A short call is the easiest way to see whether it fits your business.

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