Slack + WhatsApp API Integration — Complete Guide 2025

Your team is in Slack. Your customers are on WhatsApp. WA.Expert sends incoming WhatsApp messages as Slack notifications to your team channels — and lets team members reply from Slack. No more switching between apps to handle customer enquiries.

Connect Slack + WhatsApp → Talk to an Expert

Real-time

WhatsApp messages → Slack notifications instantly

Reply from Slack

Team members respond to WhatsApp from Slack

Any channel

Route WhatsApp alerts to specific Slack channels

Internal alerts

System events, reports, alerts via WhatsApp + Slack

What You Can Automate

Top use cases for Slack + WhatsApp API

Slack is where your team communicates. WhatsApp is where your customers communicate. WA.Expert bridges both — incoming customer WhatsApp messages create Slack notifications for your team, and team members can reply from Slack back to WhatsApp.

📨

Customer WhatsApp → Slack alert

New WhatsApp enquiry fires a Slack notification to your sales or support channel with message content.

↩️

Slack reply → WhatsApp

Team member replies in Slack thread → message delivered to customer as WhatsApp.

🚨

Alert routing

Critical system events, low stock, payment failures → WhatsApp to manager + Slack to operations channel.

📊

Daily reports → Slack

Sales performance, lead count, ticket volume → auto-sent to relevant Slack channel via WhatsApp bot.

Trigger → Action

How Slack events trigger WhatsApp messages

Slack trigger	WhatsApp action (WA.Expert)	Business impact
New WhatsApp enquiry received	Slack notification in #enquiries channel with message	Team awareness in seconds
WhatsApp from existing customer	Slack DM to assigned account manager	Personal routing
System alert (low stock, error)	Both WhatsApp (manager) + Slack (#ops)	Multi-channel alerting
Team member Slack reply	Delivered to customer as WhatsApp message	Reply from Slack
Daily sales report	Slack #sales-team + manager WhatsApp	Performance visibility

Setup Guide

How to connect Slack to WhatsApp API

Create a Slack App with incoming webhooks

In Slack API dashboard, create a new Slack App for your workspace. Enable Incoming Webhooks and create a webhook URL for your target channel (e.g., #whatsapp-enquiries).

Configure WA.Expert to forward messages to Slack

In WA.Expert → Integrations → Slack. Enter your Slack webhook URL. Select which WhatsApp events trigger Slack notifications: all messages, first message only, or keyword-triggered.

Set up reply routing (optional)

For Slack → WhatsApp replies: WA.Expert creates a Slack thread for each WhatsApp conversation. When a team member replies in the thread, WA.Expert forwards the reply back to the customer's WhatsApp.

Configure alert channels

For internal alerts (system events, sales reports): set up WA.Expert flows that send to both WhatsApp (for managers) and Slack (for relevant channels) simultaneously.

Test the integration

Send a test WhatsApp to your business number. Verify it appears in your Slack channel within seconds. Optionally, reply in Slack and verify the customer receives it on WhatsApp.

Sample Slack → WhatsApp configuration

// WA.Expert → Slack webhook
// New WhatsApp message received

POST https://hooks.slack.com/services/T.../B.../...
{
  "channel": "#whatsapp-enquiries",
  "text": "New WhatsApp from {{sender_name}}",
  "attachments": [{
    "color": "#25D366",
    "text": "{{message_body}}",
    "footer": "{{sender_phone}} · {{timestamp}}"
  }]
}

WA.Expert handles WhatsApp API authentication, template management, and message delivery. You only pass the trigger data from Slack — no WhatsApp API expertise needed.

FAQ

Slack + WhatsApp — common questions

Can team members reply to WhatsApp customers from Slack?

Yes — with WA.Expert's Slack reply integration enabled, replies posted in the Slack thread for a WhatsApp conversation are forwarded back to the customer as WhatsApp messages. This requires the WA.Expert Slack bot to be added to your workspace.

Can I route different WhatsApp messages to different Slack channels?

Yes — WA.Expert supports conditional routing. WhatsApp messages containing keywords like "order" route to #order-support, messages from VIP contacts route to #vip-team, messages outside business hours route to #after-hours. The routing rules are configured in WA.Expert.

Is this a replacement for a proper helpdesk like Freshdesk or Zendesk?

The Slack integration is best for small teams (under 10 agents) who already live in Slack and handle a manageable volume of WhatsApp enquiries. For larger teams or high-volume support, a dedicated helpdesk (Freshdesk, Zendesk) with WhatsApp integration is more appropriate as it provides ticketing, SLA tracking, and reporting.

Can I send WhatsApp alerts triggered by Slack messages?

Yes — the reverse flow is also possible. A specific Slack message or command can trigger a WA.Expert API call to send a WhatsApp. For example: a team member types /whatsapp-alert [phone] [message] in Slack to send an urgent WhatsApp to a customer or supplier.

Does the Slack integration work with Slack free plan?

Yes — the Slack incoming webhook (for receiving WhatsApp notifications in Slack) works on all Slack plans including Free. The reply routing feature requires the WA.Expert Slack bot which also works on Slack Free.

How do I prevent Slack notification overload from WhatsApp?

Configure WA.Expert to only notify Slack for first messages from new contacts, not for every message in an ongoing conversation. Use keyword filters to only alert Slack for high-priority messages (containing "urgent," "complaint," "order error"). This keeps Slack signal-to-noise ratio high.

Related Integrations

More WhatsApp integration guides

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