Request contact info for WhatsApp BSUID-only users

Build a workflow that detects inbound WhatsApp BSUID-only users with a blank phone number, asks them to share contact information, and saves the shared phone number to their Braze profile so you can merge duplicates if needed.

When a WhatsApp user messages your business with a username and no prior conversation history, Braze may create or match a profile that has a BSUID and no phone number. Requesting their contact information lets you store a phone number on that profile, check whether they already exist in your workspace, and merge duplicate users when appropriate.

Requirements

Before you build this workflow, confirm the following:

Requirement	Description
WhatsApp setup	Your WhatsApp Business Account is connected to Braze and your subscription group can receive inbound messages. See WhatsApp setup.
Contact request messaging	In the WhatsApp message composer, you can select the Request Contact Info response layout, or create or select a Request contact info template.
Inbound contact share Liquid	You can use {{whats_app.${contact_shared_phone_number}}} in a User Update step. For attribute details, see Contact shared phone number.
Merge plan	You have a plan for how shared phone numbers should resolve against existing profiles. See Merge duplicate users.

How the flow works

sequenceDiagram
    participant User
    participant Braze
    User->>Braze: Inbound WhatsApp message (BSUID only)
    Note over Braze: Entry audience: Phone Number is blank
    Braze->>User: Request Contact Info response (Share Contact Info)
    User->>Braze: Responded to contact info request
    Braze->>Braze: User Update sets Phone Number from contact_shared_phone_number
    Note over Braze: Optional: merge duplicate profiles

1. A user sends an inbound WhatsApp message.
2. Braze enters them into a Canvas only if Phone Number is blank, so the inbound sender is using a BSUID without a stored phone number.
3. Braze replies with a Request Contact Info response message that includes WhatsApp’s built-in Share Contact Info button.
4. When the user shares contact info, an Action Paths step matches Responded to contact info request.
5. A User Update step writes {{whats_app.${contact_shared_phone_number}}} to the profile Phone Number attribute.
6. You merge that profile with any existing profile that uses the same phone number, as described in Step 5.

Build the Canvas

Step 1: Create an action-based Canvas

1. Go to Messaging > Canvas and select Create Canvas.
2. Name your Canvas (for example, “WhatsApp — Request contact info for BSUID users”).
3. Under Entry Schedule, select Action-Based.
4. Under Action-Based Options, add the entry trigger Send a WhatsApp inbound message and select your Subscription group.
   • Under Condition to match, select None unless you want only specific keywords to start this flow.
5. Continue to Target Audience. In your filter group, add Phone Number is blank.

That combination—inbound WhatsApp message plus a blank phone number—targets users who are messaging with a BSUID and do not yet have a phone number on their Braze profile.

Step 2: Send a Request Contact Info response message

Because the user already messaged your business, the 24-hour conversation window is open, so we recommend a Response Message instead of a template. Complete the following steps to send the request.

1. Add a Message step.
2. Select WhatsApp > your subscription group > Response Message.
3. Choose the Request Contact Info layout.
4. Write body copy that explains why you’re asking for their phone number.
   • For example, explain that the user may already have an account and sharing contact info helps you connect their WhatsApp conversation to that profile.
5. Keep the built-in Share Contact Info button. WhatsApp provides the user’s number in a consistent format, which reduces manual typing and formatting issues.

You can still personalize the body and localize the copy as you would for any response message.

Step 3: Wait for the contact info response

1. Add an Action Paths step after the message.
2. Create a group that uses the same WhatsApp subscription group.
3. Set the condition to Responded to contact info request.

This condition matches inbound WhatsApp messages that are replies to your contact information request, so the shared phone number is available on the inbound event.

Step 4: Update the phone number on the profile

On the Action Paths branch for Responded to contact info request, update the user profile with the shared phone number.

1. Add a User Update step.
2. Update the standard Phone Number attribute.
3. In personalization, open WhatsApp properties and select the contact shared phone number attribute so the value is {{whats_app.${contact_shared_phone_number}}}.

After this step, the previously anonymous BSUID profile has a phone number and retains the WhatsApp message history on that profile.

Step 5: Merge duplicate users

Saving the phone number does not automatically merge profiles. After the number is on the BSUID profile, use your existing duplicate-resolution process to concatenate that profile into the main user when a match exists.

You can:

• Merge profiles individually
• Bulk merge duplicates
• Use rules-based merging so phone-number matches are handled consistently with the rest of your workspace

Treat this the same way you already merge duplicates created from other channels or identity sources.

Alternative setup: Split the full flow across a campaign and Canvas

Instead of building a full Canvas flow for one guided journey, you can split the same workflow into a campaign and a Canvas. Use this split when multiple upstream messages can ask for contact info and you want one shared update funnel:

1. Build a campaign that enters users on Send a WhatsApp inbound message when Phone Number is blank, then sends the Request Contact Info response message.
2. Build a Canvas that enters users on Send a WhatsApp inbound message when the condition is Responded to contact info request, then runs the User Update step (and any merge follow-up you automate).

Related articles

• WhatsApp usernames and BSUIDHow Braze stores BSUIDs and when phone numbers are still available.
• Message users (WhatsApp)Inbound Liquid attributes for contact share origin and shared phone number.
• Merge duplicate usersIndividual, bulk, and rules-based options after you acquire a phone number.