WhatsApp coexistence: use the Business app and the API on one number

For years the rule was simple and painful: the API needed a number that wasn't on any WhatsApp app, so you either gave up the app or bought a second number. Plenty of forum answers still say so. It stopped being true in 2025. Meta's rules here are as of mid-October 2026.

What WhatsApp coexistence is

Meta's documentation calls it onboarding WhatsApp Business app users and notes it's “sometimes referred to as Coexistence”. Your number stays registered on the WhatsApp Business app. A provider connects the same number to the Cloud API, and from then on messages are mirrored: what customers send arrives in both places, and what you type on your phone reaches the provider too. Meta's developer docs call those copies of your own messages “message echoes”. Meta notes a few exceptions: a message from a customer using a companion device Meta doesn't support shows only in the app, and a customer's very first message can occasionally show only in the app.

So, where Meta allows it, a team inbox or an AI agent can work the number while you still answer from your pocket. In Zymbler, a reply you send from the phone shows up in the inbox and pauses the agent in that chat, so you and the agent don't answer the same customer at once. With Let the AI pick the conversation back up on, the agent answers again once you've been quiet for the hours you set (1 to 24) and the customer writes again.

Requirements before you start

From Meta's documentation:

• WhatsApp Business app version 2.24.17 or later on the phone that holds the number. If Meta's window says “Update your WhatsApp Business App to the latest version to use this phone number”, update and start again.
• The number is on the WhatsApp Business app, not regular WhatsApp. Otherwise Meta says “Your phone number isn't registered with WhatsApp Business.” If it's on regular WhatsApp, install WhatsApp Business on the same phone; it offers to move the number and your chats.
• The number is in use on the app. Meta can refuse a number with “Your phone number isn't eligible to connect to the WhatsApp Business Platform.” Its advice: “More activity on the WhatsApp Business App is needed to help determine eligibility.” Meta doesn't say how much activity is enough.
• A Meta Solution Partner or Tech Provider. Coexistence runs through the provider's Embedded Signup, Meta's connect window, which the provider has to set up for Business app numbers. Meta documents no way to switch it on yourself. Zymbler handles that part for you.
• No other partner still attached. If the account is already shared with a partner, Meta says “Switching partners is not supported in this flow” and asks you to disconnect the current partner in the WhatsApp Business app first. Meta adds that a credit line still shared with a past partner can cause an error too.
• A number from a region Meta supports. See the table below.

Which countries support coexistence

Meta added countries in stages. The dates are from Meta's WhatsApp changelog, whose launch entry names no countries:

Meta's coexistence guide no longer lists any excluded countries. Meta can still refuse a number with its error “This feature is unavailable for phone numbers from this region”, and Meta's window has the final say on your number.

Business app only, API only, or coexistence

With Zymbler as the provider:

Who coexistence suits, and who it doesn't

It suits you if you already sell on the WhatsApp Business app and:

• You want an AI agent or a team inbox to answer, especially out of hours, while you still reply from your phone.
• You've outgrown broadcast lists and want to send approved templates to many customers.
• You don't want to change the number on your cards, ads and website.

It's a poor fit when:

• The number also carries personal or family chats. Once you connect, those reach your provider too, and WhatsApp's terms say the Business app is “not for personal use”.
• You sell mostly in group chats. Groups stay in the app and aren't synced.
• Your team relies on WhatsApp for Windows, which Meta doesn't support as a linked device here. WhatsApp Web works.
• You send at very high volume. A coexistence number is capped at 20 messages a second (more on that below).

What changes on your phone

Meta's own feature comparison lists what changes in the WhatsApp Business app once the number is connected:

• Editing and deleting sent messages still work in one-to-one chats.
• Disappearing messages, view once and live location are turned off for all one-to-one chats.
• Broadcast lists become read-only, and you can't create new ones. To message many customers, send an approved template through the API. In Zymbler that's a Workflow.
• Group chats work in the app as before but aren't synced to the API.
• Still work in the app, but not through the API: voice and video calls; business tools such as catalog, orders and status; messaging tools such as marketing messages, greeting and away messages, quick replies and labels; your business profile; and WhatsApp Channels.
• Linked devices are all unlinked when you connect. You can re-link up to four. Meta says every companion app is supported except WhatsApp for Windows and WhatsApp for Wear OS.

Greeting and away messages set in the app keep working after you connect, and they can clash with the agent. If an agent answers for you, switch them off in the app.

Chat history and sync

When you connect, Meta asks on your phone whether to share your chat history with the provider. Meta's rules:

• One-to-one chats from the last 180 days come across.
• Photos, videos and files come across only for messages from the last 14 days. Older media messages arrive without the file. Zymbler imports the text of your chats: an imported photo, voice note or file shows as a placeholder such as “[Photo]”, and the file itself stays on your phone. Photos and files customers send after you connect do show in the inbox.
• Contacts that have a WhatsApp number come across.
• The provider has 24 hours after you connect to sync your history and contacts, and can request each only once. To repeat it, disconnect in the app and go through signup again.
• Meta advises keeping the WhatsApp Business app open on your phone while the sync runs.

Zymbler asks Meta for your history and contacts automatically as soon as the number goes live. Progress shows under the number in Channels: Importing your chats…, then Your chats are in with a count of conversations and messages. If you chose not to share, it says Chat history wasn't shared, and new messages still arrive normally. If Meta turns down the request, it says We couldn't import your chats and offers Retry import, which works for 24 hours after connecting. Meta never accepted the first request, so a retry is still the one request Meta allows.

Zymbler uses the contacts Meta shares to put names on conversations, and doesn't create a contact for anyone who hasn't had a conversation. When one of those customers writes again, the agent can see their earlier messages. Imported contacts start without a lead score, which builds from the new conversation.

Throughput: 20 messages per second

Meta fixes a coexistence number's throughput at 20 messages per second, “to remain compatible with the WhatsApp Business app”. A number on the Cloud API alone gets up to 80 by default. For a small business that ceiling rarely matters. Zymbler's Workflows send to 20 contacts every 10 seconds, well under the ceiling.

Keeping it connected

Meta can disconnect a coexistence number from the API when:

• the phone with the WhatsApp Business app isn't used for about 14 days;
• you register the number on the regular WhatsApp app;
• you change the number in the WhatsApp Business app;
• you re-register the Business app on a new device. Meta says reconnecting then runs automatically, unless you opt out, and usually completes within a few minutes.

Your chats stay on the phone. If the number drops off, open the Business app, then connect again from Channels in Zymbler.

What it costs

Meta says messages you send from the WhatsApp Business app “will continue to be free”. Messages sent through the API, including an AI agent's replies, follow WhatsApp Business Platform pricing. Since 1 July 2025 Meta has billed per delivered message, and since 1 October 2026 that includes replies inside the 24-hour window. Each business phone number gets 1,000 free service messages a month. Meta bills these fees to your own WhatsApp Business account.

Meta says messages from the app “do not create, extend, or affect” the API's 24-hour window. And if a customer wrote just before you connected, Meta says the API can only answer them with a template, because no window was opened on the API side. You can still reply from the app. See what changed on 1 October 2026 or estimate your own bill with the WhatsApp pricing calculator.

How to set it up

The steps are the same with any provider; the button names below are Zymbler's.

When coexistence doesn't show up

Meta's own error messages, one by one, are in WhatsApp coexistence not working or number ineligible. These are the cases we've run into connecting businesses' numbers, most common first.

“This number is already registered to a WhatsApp account”

You entered the number and Meta asked you to “Add your WhatsApp phone number”, then refused it. Meta didn't offer coexistence. In the cases we've seen, the cause was the Facebook login in the window: a staff or agency account only sees its own business portfolios, so Meta treats the number as someone else's. Have the person who owns the business portfolio run the connection with their own Facebook account.

“Ineligible: this number can't be shared with this app”

It's the “no other partner still attached” requirement above, as it shows up in practice. The number's WhatsApp Business account is still tied to another provider, as a partner or through their credit line. Meta's fix: in the WhatsApp Business app, go to Settings → Account → Business Platform and disconnect the current partner, then try again. If you still share a past provider's credit line, ask them to stop sharing it.

How to switch it off safely

Disconnect from the phone: in the WhatsApp Business app, Settings → Account → Business Platform → Disconnect Account. Providers can't deregister a coexistence number through the API, and in our experience, forcing a number off from the provider side can knock it offline for customers. The app is the safe way out, and your chats stay on the phone.