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

You had to pick one. Not anymore. Meta has rolled out a capability — officially "API Solutions for Business App Users," known across the market as WhatsApp Coexistence — that runs the mobile app and the Cloud API on a single shared number, with two-way, real-time synchronization. Sandra now supports it natively.

What Coexistence actually is

Coexistence lets a single number operate in two environments in parallel: the mobile app the agent keeps on their phone, and the Sandra platform, connected to the WhatsApp Business API. The two stay in sync at all times.

If an agent sends a message from their phone, it shows up in Sandra (as an echo message). If Sandra sends an automated notification or an AI-agent reply, the agent sees it in their chat thread.

The problem it solves: the "invisible channel"

In many organizations, sales reps, advisors or field technicians already use WhatsApp Business to talk to customers, straight from their mobiles. It works very well at the individual level. At company level, it creates real problems:

• No visibility into what was said, to whom, or when.
• Data loss: when an employee leaves, their customer conversations leave with them.
• Compliance risk: exchanges live on a personal device with no archiving — an issue for GDPR and Swiss nFADP (nLPD).
• No oversight: no measurement of response times, no after-hours automation.

Coexistence removes the binary choice between agent mobility and company control. The agent carries on exactly as before; the company gains access to every conversation, plus automation and archiving.

App only, API only, Coexistence: the comparison

How to activate it on Sandra

Activation runs through Meta's secure flow (Embedded Signup), with no involvement from your technical team. In your Sandra workspace, the Settings → WhatsApp Integration page offers two options: create a new Cloud API number, or connect an existing number in coexistence.

1. Choose "Existing number (coexistence)" In Sandra, under WhatsApp Integration, select the option to connect a number already active on the WhatsApp Business app.
2. Authorize via Meta & scan the QR You authenticate the Facebook Business account, then the agent scans a code from "Linked devices" in their WhatsApp Business app.
3. Start the sync You confirm the permissions and choose whether to import the last 6 months of history. Two-way synchronization is then live.

Plan for roughly 15–20 minutes of onboarding per agent, history included.

Benefits for the company — and for the agent

For the company

• Immediate visibility into a channel that already existed but stayed invisible.
• GDPR / nFADP compliance: conversations move from the agent's personal phone to centralized archiving — and with Sandra, hosted in Switzerland.
• Operational oversight: response times, volumes, performance per agent.
• Progressive automation: start with visibility, then add AI agents, message templates and proactive notifications at your own pace.

For the agent

• No tool change: they keep the same WhatsApp Business app.
• Native features preserved: voice and video calls, statuses and catalog remain available in the app.
• Help without interference: an AI agent can handle after-hours questions; the agent takes over whenever they want, simply by typing.

The limits to know before you start

Any serious technology deserves an honest look at its constraints too. Here are the points documented by Meta:

• WhatsApp Business app required — not the personal version. Agents on standard WhatsApp must first migrate to the Business version (2.24.17 or later).
• Throughput capped at 20 messages/second on a coexistence number, to stay compatible with the app. Worth keeping in mind for mass broadcasts.
• Features disabled in the app after connecting: broadcast lists become read-only; disappearing messages, "view once" and live location sharing are turned off for individual chats.
• No sync for groups or unsupported companion devices (WhatsApp for Windows and WearOS).
• The app must be opened regularly: at least once every 14 days to keep the connection active.
• Unsupported countries: Nigeria and South Africa are not yet supported. Europe (including Switzerland and France) is.
• Bot / human collision risk: if an agent replies manually while a bot is active, the customer can receive two answers. This is handled with handoff rules that Sandra orchestrates to pause the AI as soon as a human steps in.

Who is it for?

Coexistence is especially relevant for distributed sales teams, field teams (technicians, real-estate agents, advisors) and regulated sectors — banking, insurance, healthcare, education — where mobile remains the working tool but the company needs control, traceability and compliance. If you ruled out the API for fear of disrupting your agents or losing your history, now is the time to reconsider.

Frequently asked questions

Conclusion

Coexistence isn't a revolution: it's the end of a limitation that forced businesses to choose between their teams' mobility and control over their communications. For brands whose teams already use WhatsApp day to day, it's a path to professionalizing the channel without disruption — visibility, measurement, compliance and progressive automation, without the agent losing anything.

Sandra helps companies set up these conversational journeys, from connecting the number to CRM integration, on a platform hosted in Switzerland and compliant with GDPR and Swiss nFADP.