WhatsApp Coexistence: how to use the app and official API on the same number

What changes in the app

Coexistence is not free in features. When connected, part of the app changes behavior, and it’s better for the team to know beforehand than discover it during service. According to Meta’s documentation:

• Broadcast lists: existing ones become read-only and new ones cannot be created. Sending to many contacts is done via the API, with templates.
• Groups: remain on the phone but are not synchronized with the system.
• Temporary messages, view-once, and live location are disabled in individual chats.
• Voice and video calls and channels are not part of the synchronization.

For most companies, only the broadcast list matters. And it matters for a good reason: it was precisely the feature used for uncontrolled mass sending, which now goes to the right place.

History and contacts: what comes along

When connecting, the company can synchronize what already exists in the app:

• Conversations from the last 6 months can be brought into the connected system. Synchronization must happen within the first 24 hours after connection.
• Contacts with WhatsApp can also be synchronized.
• Messages older than 6 months remain on the phone but do not enter the system.

During synchronization, Meta advises keeping the app open on the phone. It’s an operational detail that avoids the most common first-day question: "Why didn’t the old conversations appear?"

Speed, cost, and quality

Three points to consider before deciding:

• Sending speed. Numbers in coexistence have a fixed throughput of 20 messages per second on the API. For small and medium business service and campaigns, this is more than enough; for those sending to hundreds of thousands of contacts at once, it may be a limit.
• Cost. What the company sends via the app remains free. What is sent via the API follows Meta’s pricing: marketing template messages, authentication, and utility messages outside the service window are charged; replies within the 24-hour window are not. Details at Meta conversation pricing.
• Quality and sending limit. The number receives a quality rating and daily contact limit, like any official number. See sending limits and how to upgrade tiers.

The Two Doors Map: who answers where

The biggest risk of coexistence is not technical, it’s procedural. With two open doors for the same number, two people might answer the same client, or no one answers because each thinks the other saw it. The solution is to decide in writing what goes through each door:

• App door (phone): old clients who speak directly with the owner, groups, quick replies outside business hours when only she is available.
• System door (API): every new lead, every conversation with an assigned responsible, campaigns and reminders with approved templates, automation, and reporting.
• Passing rule: if the conversation started on the phone and became a negotiation, it gets assigned in the system — and whoever was on the phone stops responding there.
• Silence rule: no conversation with an assigned responsible in the system is answered on the phone without notifying the responsible party.

It may seem bureaucratic, but it prevents the client from receiving two different answers within five minutes — the fastest way to lose the trust the number has built over years.

Step-by-step connection

1. Confirm the number is on WhatsApp Business, not personal WhatsApp, and that the app is updated.
2. Have administrator access to the Meta business portfolio or create one during the connection flow.
3. Start the embedded registration through the tool that will use the API and choose to connect a number from the app.
4. Scan the QR Code with the WhatsApp Business app on the phone.
5. Authorize synchronization of contacts and conversations and keep the app open until finished.
6. Create and submit the first message templates for approval — reminder, conversation restart, confirmation.
7. Train the team on the Two Doors Map before releasing the dashboard to everyone.

To approve templates on the first try, see how to write and approve templates.

A clinic’s account that didn’t want to change numbers

An aesthetic clinic has used the same number for seven years, with about 4,800 contacts. The owner answers on the phone; two receptionists share a second device. The clinic loses on average 22% of appointments due to no-shows without notice, on a schedule of 360 appointments per month with a ticket of R$ 180.

• Switching to a new number on the API would mean notifying 4,800 contacts and, according to the owner’s estimate, losing some clients who only saved the old number.
• With coexistence, the number was connected to the API without leaving the phone. The owner continued answering old clients via the app; the receptionists moved to the dashboard.
• The clinic created a confirmation template sent the day before. No-shows dropped from 22% to 13%.

Nine percentage points fewer no-shows in 360 appointments equals about 32 saved slots per month: R$ 5,760. Reminders cost per utility message outside the window, a fraction of that. And no client had to save a new number.

The first 30 days after connecting

The connection takes minutes; what decides if it worked is the first month. A simple week-by-week plan:

• Week 1 — check. Verify if conversations from recent months appeared on the dashboard, if messages sent from the phone are entering the system, and if messages sent by the system appear on the phone. Note any conversation left out and check if it’s older than 6 months or a group chat.
• Week 2 — door division. Apply the Two Doors Map with the entire team. Every new lead gets assigned in the system. The owner decides which clients she continues to serve via phone.
• Week 3 — first template in use. Put a single utility template into production, like appointment confirmation or order notice. Monitor response rate and if anyone blocks.
• Week 4 — quality review. Check the number’s quality rating and sending limit. If green, the next step is a restart template for recent conversations — always for those who have reason to expect the message.

This pace may seem slow but protects the operation’s most valuable asset: an old, known, and trusted number. Rushing in the first days usually harms quality right away.

Questions the team will ask

• "Will the client notice any change?" No. The number, name, and photo remain the same. They only notice if they receive duplicate answers — which the Two Doors Map prevents.
• "Can I keep sending audio from the phone?" Yes. Regular messages via the app continue working and appear in the system.
• "What if I change phones?" Change the app carefully and check the connection afterward; the number remains registered on the official platform.
• "Why can’t I create broadcast lists?" Because sending to many contacts is now done with approved templates via the API, with permission and quality control.

When coexistence is not the best choice

• The company depends on broadcast lists and doesn’t want to switch to approved templates. In this case, coexistence removes the feature they use.
• The sending volume is very high and the throughput of 20 messages per second cannot handle the operation.
• No one answers on the phone anymore. If all service already happens on the dashboard, the number can move to the API without coexistence, without app limitations.
• The number has a history of complaints due to old sends. Quality will be measured from day one on the API; it’s worth cleaning behavior beforehand.

Common mistakes in coexistence

• Not informing the team that broadcast lists will stop. Someone tries to send the weekly campaign and thinks the system broke.
• Leaving the app during synchronization. Old conversations stop appearing on the dashboard.
• Answering the same client through both doors. Without a passing rule, coexistence becomes confusing.
• Using the API as a license to blast the entire contact list. Saved contact is not a contact who gave permission; quality drops and limits decrease.
• Confusing with common QR Code connection. Only coexistence registers the number on the official platform; the other remains outside the rules.

Properly used, coexistence is the smoothest migration to the official API: the number stays, recent history comes along, and the app remains in the pocket of those who always answered. What changes is that what needs scale happens in the right place.