Customers on WhatsApp. The team in Slack.
WhatsApp customer support automation lets customers message on the channel they already use while the team replies from Slack, without sharing a phone or WhatsApp login.
The situation
The company wanted WhatsApp as a way for customers to reach it, starting immediately after signup. That is straightforward until you look at either end of the conversation.
The company sells several products in one ecosystem, so messaging every new signup would have welcomed people who had already been customers for a year. On the team side, people across sales and customer success needed to see what customers were saying. A shared WhatsApp account or shared phone was the obvious answer, but neither was a real option. The team was already in Slack all day.
The constraint
Both ends of the problem are permission problems, and the second is easy to miss. More people can see a Slack channel than should be able to message customers from it. Visibility and authority are different things, and a shared inbox quietly merges them unless something prevents it.
The workflow checks the Slack identity of whoever posts a reply and forwards it to WhatsApp only when that identity is approved. Everyone else can read the conversation, follow it, and discuss it in the thread, but none of that reaches the customer. Slack becomes a shared interface without channel access becoming permission to contact customers.
The outbound side has its own gate. Before any welcome message goes out, the system checks whether the person already has an active subscription to any product in the ecosystem, so only genuinely new users enter the flow.
Timing is the third constraint. An automated welcome at eleven at night invites a reply nobody will see until morning, so messages go out only on approved days and within approved business hours. Signups outside that window are queued until the next one opens.
What we built
On signup, the system checks for an existing subscription. Only genuinely new users receive a WhatsApp welcome within the approved business-hours window. From there, the customer simply uses WhatsApp.
Incoming messages route into a dedicated Slack channel, one thread per customer conversation. Approved team members reply inside the thread, and the message goes back out through Twilio. Anyone else posting in the thread is talking to colleagues, not the customer. Images, video, and audio move in both directions, so a customer screenshot of a problem appears in Slack rather than as a note saying an attachment was received.
Process diagram
Where it stands
Customers stay on WhatsApp. Sales and customer success stay in Slack. Nobody shares a phone or logs into a WhatsApp account, and the company does not need to build or buy a separate support tool to make it work.
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