What is WhatsApp coexistence? Keep the number on the phone and use the API

By Qilin Software Lab Private Limited · Published 2026-10-14 · 4 min read

For years a WhatsApp business number could be in one of two places. Either it lived on a phone running the WhatsApp Business app, with the owner replying by thumb, or it was migrated to the WhatsApp Business Platform (the Cloud API), where software answers and the phone goes quiet. Moving to the API meant losing the app: the number was wiped from the handset, chat history with it, and the owner now needed a web inbox to see anything at all.

Coexistence is Meta's name for the third option. The same number stays on the WhatsApp Business app and is registered on the Cloud API. The owner keeps chatting from the phone. Your software receives the same conversations through a webhook and can reply through the API. Both sides see one thread.

What coexistence gives you

The phone keeps working. Chats, calls, status, catalog, the quick replies the owner already uses. Nothing is retrained.
The API sees business chats. One-to-one messages from customers arrive at your webhook as JSON, and replies sent through the API appear in the app thread, marked as sent from a linked system.
History can be imported. On onboarding Meta can sync recent one-to-one chat history (Meta currently allows up to six months) so your CRM does not start blank.
Templates outside the 24-hour window. API sends after a customer has been silent for a day need an approved template, exactly as on any Cloud API number.

What stays out

Groups. Group chats are not shared with the API. If the business runs its dealer network in a group, that stays on the phone only.
Personal WhatsApp. Coexistence is for the WhatsApp Business app. A personal-app number has to move to the Business app first.
Some message types. Meta's documentation lists the types that are not mirrored between app and API (for example, view-once media). Treat the webhook as a faithful feed of normal business conversation, not a byte-for-byte copy.

How a business turns it on

The onboarding runs through Meta's Embedded Signup, the same guided window used for every Cloud API onboarding, with a coexistence option. The business owner signs in to Facebook, chooses or creates the business portfolio, picks "use the number on my WhatsApp Business app", and scans a code from the app's linked-devices screen. Meta verifies the number, creates or reuses a WhatsApp Business Account, and shares it with the technology provider that launched the signup. The whole thing takes two to three minutes and happens on a phone the owner is already holding.

A technology provider such as NumberBridge then does the invisible part: exchanges the signup code for a business token, subscribes the account to its webhook, and starts delivering messages to the customer's own endpoint.

Who it is for

Coexistence fits the business that is not ready to give up the phone: a trading firm whose owner has fifteen years of customer relationships in one handset, a clinic whose receptionist replies between patients, a distributor where the accounts person forwards invoices from the same number. It lets software (a CRM, an ERP such as Tally, an AI assistant) join that number without asking anyone to change how they work.

It is less necessary when the number was never on a phone: a new support line, a notifications-only sender, a call-centre queue. Those are better as plain API-only numbers, which the same connector can register for you.

Cost

Meta bills conversations to the business's own WhatsApp Business Account at its published rates; the connector should not mark them up. NumberBridge charges a flat monthly fee by number of connections, see pricing.

Put software on your business number without losing the phone

NumberBridge connects an existing WhatsApp Business app number to the Cloud API in two minutes. Flat monthly fee, no per-message markup, 14-day trial.

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