Coexistence: the WhatsApp Business app and the API on one number

If your business number has been on the WhatsApp Business app for years, your customers know it and your conversations with them live in it. Connecting that number to the official WhatsApp API used to mean giving up the app: Meta says a number registered on the API cannot be used with WhatsApp Messenger, and a number already in use on WhatsApp cannot be registered on the API until it is deleted there first.

Coexistence changes that. This guide covers what it is, what works where, what it costs, how to set it up and undo it, and how it works with ATMET Chat.

What is WhatsApp coexistence?

Coexistence is Meta's way of running the WhatsApp Business app and the official WhatsApp API (WhatsApp Cloud API) on one number at the same time. Meta's documentation calls it "Onboard WhatsApp Business app users" and notes that it is sometimes referred to as "Coexistence" in support channels and partner documentation.

Meta sums it up this way: once onboarded, the business can send high volumes of messages through the API, can still message customers one to one from the WhatsApp Business app, and WhatsApp keeps the message history in sync between the two.

Coexistence is Meta's feature, not any one provider's. A business turns it on from the signup page of the partner it uses to connect its number to the API, and any partner that supports it can offer it.

Who is coexistence for?

It suits a business that answers customers from the WhatsApp Business app and wants more than the app alone gives, without changing its number or its phone. For example:

• An online store that wants to send order notifications and campaigns on Meta-approved templates from the number its customers already know.
• A clinic, restaurant or salon that wants its team to work on conversations from one inbox while the owner keeps replying from the phone.
• A business that gets many repeated questions and wants automatic replies to them, without losing the one-to-one chats in the app.

If your number is on the regular WhatsApp app rather than the Business app, coexistence doesn't apply to it. The difference between the two apps and the API is in our comparison of regular WhatsApp, the Business app and the API.

What do you need before you start?

• A number on the WhatsApp Business app. Coexistence is for numbers already on the app, which is why Meta skips the step of registering the number on the API.
• WhatsApp Business app version 2.24.17 or later. Update the app before you begin.
• Your primary phone in hand. During setup a message arrives in the app for you to confirm the connection, and Meta advises keeping the app open while the history syncs.

If the official WhatsApp API is still unclear to you, start with our guide to the official WhatsApp API and when you need it.

What works in the app and what works through the API?

The app mostly stays as you know it, but the API doesn't support everything the app does. Here is what Meta lists:

As for media in the synced history, such as photos and files, the API can retrieve only what was sent in the 14 days before onboarding.

What stops in the WhatsApp Business app after you turn it on?

Three things change in the app itself:

• Broadcast lists: they stop. You can't create a new list, and existing lists become read-only. Sending to many customers moves to the API, on Meta-approved templates.
• Disappearing messages, view once and live location: they stop in one-to-one chats.
• Linked devices: every device linked to the number is unlinked at onboarding, and you can link them again, up to four. That includes ATMET Chat channels if they were linked before onboarding, since they link your number as a linked device, so link them again afterwards. Coexistence doesn't support WhatsApp for Windows or WearOS watches.

Everything else, such as groups, calls, the catalog and quick replies, stays in the app but doesn't work through the API.

What do messages cost with coexistence?

Messages you send from the WhatsApp Business app stay free, as they always were. Messages that go out through the API follow Meta's API pricing:

• Meta charges per message, and only when it is delivered. It doesn't charge for the messages customers send you.
• The first 1,000 replies to your customers each month are free from Meta, per number, and since October 1, 2026 Meta charges the replies after that at its service rate.
• Template messages, such as campaigns, are charged at their category's rate in the customer's country.

You pay Meta's fees to Meta directly, from the payment method on your WhatsApp Business account, and ATMET adds no markup. Each country's rates are on the Meta pricing page.

Are there limits on sending speed?

Yes. Meta sets a fixed speed of 20 messages per second for a coexistence number, while the API's default is up to 80 messages per second. So a large campaign on a coexistence number takes longer to go out in full.

On top of speed, Meta sets a daily limit on how many customers you can start a conversation with on a template, outside the customer service window. The limit starts at 250 customers in 24 hours and rises in steps. It is counted at the level of your business portfolio on Meta, so all your numbers share it. The details are in our guide to the official WhatsApp API.

How do you set up coexistence, step by step?

These are the steps as Meta describes them. They start on the signup page of the partner you use to connect your number:

1. Enter your WhatsApp Business app number on the signup page.
2. Wait for a message in the app from the official Facebook Business account.
3. In that message, tap "Connect to the Business Platform".
4. Choose whether to share your chat history by tapping "Confirm" — sharing is optional.
5. Copy the verification code and paste it into the signup page.
6. Finish signing up.

The WhatsApp Business app then refreshes and shows that the number is connected to the API.

If you chose to share your history, the partner has to finish syncing it within 24 hours, or you'll need to go through the steps again from the start. That's why Meta advises keeping the app open while it syncs.

How do you turn coexistence off?

From the WhatsApp Business app itself: open Settings, then Account, then Business Platform, then Disconnect Account. The number's connection to the API then stops.

The number can also be disconnected without your asking, for reasons Meta lists — see the FAQ at the end of this article.

What changes for your team day to day?

• Replying from the phone carries on. Whoever replies from the app keeps messaging one to one as before, and WhatsApp keeps the messages in sync between the app and the API.
• Automated messages go out from the same number. Notifications, campaigns and automatic replies are sent through the API from the number your customers know.
• Broadcasts move to templates. Broadcasting from the app is no longer available, so messages to many customers go out on Meta-approved templates, and only to people who agreed to hear from you, as Meta requires.
• What needs the app stays on the phone. Calls, the catalog and groups stay in the app.

Agree from the start who answers what, so two people don't reply to the same customer.

How does coexistence work with ATMET Chat?

In ATMET Chat it's called "Coexistence Mode": running the official connection while keeping the WhatsApp Business app active on your phone at the same time. If your number is on the WhatsApp Business app, the official connection doesn't make you give up the app — you keep working on it, and ATMET Chat replies from the same number at the same time.

ATMET Chat connects a number in two ways, and both are on every plan:

• The official connection (WhatsApp API): Meta's official WhatsApp API. It carries campaigns on Meta-approved templates and interactive messages with buttons and lists, and it is what coexistence runs on.
• ATMET Chat channels: they link your number as a linked device, like WhatsApp Web, so the app on your phone keeps working as usual. They are completely free, over ATMET Chat's servers, and suit day-to-day replies; they have limits on sending speed and don't support bulk campaigns.

The order ATMET Chat recommends: start with the official connection (WhatsApp API), then add ATMET Chat channels. When a number is connected both ways — what ATMET Chat calls "Dual connection" — the two work together.

Why add ATMET Chat channels? Because some of what the API doesn't support comes through them:

• Labels: the labels you put on conversations in ATMET Chat sync live with the WhatsApp Business app on your phone through ATMET Chat channels; they don't sync over the official connection alone.
• Groups: from Pro, WhatsApp groups reach the inbox only through ATMET Chat channels.

And from the Pro plan, AI answers your customers from the same number and hands the conversation to your team whenever it needs a person.

The details of coexistence and the two connection methods are on ATMET Chat's home page.