Connect an Existing WhatsApp Number (Coexistence)

TL;DR

This article explains how to connect a number that’s already active in the WhatsApp Business app to a Mumble account using Meta’s Coexistence feature. The connection is made by scanning a QR code through “Linked devices” in the app, and it doesn’t replace the app. After connecting, the number works in parallel across two channels: you can keep writing from the app, and you can manage the same conversations from Mumble too — but there are important sync limitations you need to understand up front.

Background: what Coexistence is

Coexistence is Meta’s feature that lets the same number operate in parallel both in the WhatsApp Business App and through the WhatsApp Business API. The number stays the same, the same number your customers have, and you can choose where to handle each conversation. Most day-to-day management happens in Mumble (campaigns, automations, chatbot, team), while the app stays available for personal replies from your phone. If your number doesn’t exist in any WhatsApp app, use the new-number path (link at the end).

Before you start

Access to the WhatsApp Business app with the number. The device the number is registered on needs to be in your hands, open, and available to scan a QR code in real time.
App version 2.24.17 or higher. Meta requires at least this version for the feature to work. Update WhatsApp Business through the app store before you start.
Access to Facebook Business Manager. The number will be linked to an existing business portfolio, or to a new one you create during the process.
The number isn’t connected to another API provider. If the number is currently with another WABA provider, you need to disconnect it there before you start. Meta won’t allow a double connection.
A payment method for Meta. Meta charges for every conversation opened through the API. This is set up after the connection, but it’s worth preparing a card in advance.

Connection steps

Opening the WABA Onboarding popup. When you log into Mumble without a connected number, a popup called WABA Onboarding appears. Click it and choose “Connect through Meta.”
Logging into Meta and choosing a business portfolio. You’ll be taken to Meta’s official connection screen. Log in with your Facebook user, choose the right business portfolio, and approve the permissions Mumble requests. If your browser is logged into several Facebook accounts at once, log out of the others beforehand so you don’t accidentally choose the wrong portfolio.
Choosing “Connect with WhatsApp Business.” At the connection-type step, choose the option that fits an existing number in the app. Meta will display a QR code on the screen.
Scanning the QR code from the app. Open WhatsApp Business on the device, go to settings, choose “Linked devices,” and scan the code shown on your computer screen. Confirm the connection on the device.
Waiting for the process to finish. After the scan, Meta registers the number to the WABA. This takes a few seconds to a minute. When it’s done you’ll be returned to Mumble and the number will appear connected in the WhatsApp Account Status card on the main screen.

Adding a payment method in Meta

The connection itself isn’t enough to send API messages. Meta requires a payment method linked to the account in order to charge for active API conversations. As long as there’s no card, messages sent through Mumble won’t go out, even if everything looks fine in Mumble. Messages sent directly from the app will keep working for free, which can be confusing during testing.

In Mumble, go to “Settings.”
Scroll to the billing and payments area.
Click “Add payment details.” You’ll be taken to Meta’s payment screen.
Add a credit card or another payment method, and save.

Sync limitations after connecting

This is the most important area to understand up front, so you aren’t surprised by behavior that looks like a malfunction. Coexistence is not a perfect mirror between the app and Mumble. There are real gaps in the way messages flow between the two channels.

Outgoing messages from the app don’t open a conversation in Mumble

If you write to a customer directly from the WhatsApp Business app on your phone, the conversation won’t automatically open in the Mumble inbox. If the conversation is already closed on the Mumble side, it will stay closed. The reason is that Meta doesn’t open a conversation window in the API for messages that go out from the app, only for messages that go out from the API. The practical meaning: if your team works from Mumble, it’s better to write from Mumble too, so the conversation appears and is managed there.

Messages from WhatsApp Web may not reach Mumble

If you send a message from WhatsApp Web in a browser, the message will reach the customer and also appear on your phone, but it won’t always appear in Mumble. The behavior depends on Meta’s limitations on linked devices. Practical recommendation: for a send you want to appear in Mumble, send it from Mumble.

Additional gaps that Meta defines

In addition to the two limitations noted above, there are gaps that Meta sets on every Coexistence connection:

Group chats. Meta doesn’t sync groups to the API. Groups you have in the app won’t appear in Mumble.
Broadcast Lists. After connecting, the app won’t allow creating new Broadcast Lists. Existing lists will remain read-only. Sending to many people goes, from here on, through Mumble campaigns.
Disappearing messages, View Once, Live Location. Meta disables these features in 1:1 conversations after connecting.
Voice and video calls. These stay in the app only and aren’t available through the API.
In-app business tools. Catalog, orders, statuses, as well as communication tools like greeting message, away message, quick replies, and labels, stay in the app but aren’t accessible from the API side.
Send rate. Numbers running in Coexistence are limited to 20 messages per second, lower than numbers running on the API only.
Dual pricing. Messages sent from the app will continue to be free. Messages sent through the API are charged at Meta’s Cloud API pricing. The two channels are billed separately.

The full, up-to-date list is in Meta’s documentation under Onboarding WhatsApp Business app users.

How to know the connection succeeded

On Mumble’s main screen, in the WhatsApp Account Status card, four pieces of data that come directly from Meta will appear:

Display name. The name customers will see. Usually this is the business name that was already registered in the app.
Account quality. Meta’s rating. In a Coexistence connection the number usually enters with green quality, based on its history in the app.
Meta messaging limit. The number of new customers you can initiate a conversation with in 24 hours.
Sending state. If the card is loaded and the settings are valid, it will show “Active.”

In addition, the WhatsApp Business app on the device will show a message inside it that the number was connected to the API. That’s another confirmation that the connection succeeded.

Common issues

The QR code won’t load or has expired

Cause: Meta’s QR code is valid for a minute or two. If it took time to open the app, it will expire. Solution: click refresh the code on Meta’s connection screen, and scan the new code from the app immediately.

“Linked devices” in the app shows the number is already connected to the API

Cause: the number is already with another WABA provider, or in your own WABA account from the past that wasn’t cleared. Solution: go into the platform where the number is registered and disconnect it there. Only after it’s released will Meta allow you to scan it again into Mumble. If you don’t know where the number is registered, you can check through Facebook Business Manager in the WhatsApp Accounts tab.

A conversation you write to from the app doesn’t appear in Mumble

Cause: this isn’t a malfunction, it’s the behavior Meta defines. Messages going out from the app don’t open a conversation window in the API. Solution: for the conversation to appear in Mumble, the customer needs to write to you, or the first send needs to be made from Mumble using a message template.

The app version doesn’t support the connection

Cause: the WhatsApp Business version on the device is older than 2.24.17. Solution: update the app through the app store and restart it before scanning the QR code.

After connecting, messages come in but won’t go out from Mumble

Cause: in most cases, there’s no payment method on the Meta account. Solution: Settings in Mumble, the billing area, “Add payment details.” If the problem continues even with a valid card, check the WhatsApp Account Status card on the main screen, and you’ll likely see a specific reason there, such as poor quality or a missing approved Display Name.

The bottom line

Coexistence lets you keep working with the app and at the same time unlock all of Mumble’s capabilities on the same number, but it isn’t a perfect mirror between the channels. If your team works from Mumble, send from Mumble, so the conversation opens and is managed in the right tools.

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Connecting an Existing WhatsApp Business Number to Mumble (Coexistence)

Mumble Team