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Calling · 4 min read

WhatsApp Calling

Take and make calls in the browser — over SIP, TLS-secured.

FlowsDesigner integrates with Meta's WhatsApp Calling API via SIP trunks. Both directions work in your browser — no softphone needed.

How it works

  • Meta sends an inbound SIP INVITE to our Asterisk PBX
  • Asterisk dials your browser's SIP user agent over WSS
  • Your browser accepts the call; audio flows via WebRTC (TURN-TLS-443 in restrictive networks)

Setup

Settings → Phone Numbers → for each number, click Provision calling. We auto-generate the Asterisk trunk config + Meta SIP password.

Controls

In the call panel: Mute, hold, hang up. The conversation is also logged in the inbox.

WhatsApp Web compatibility

Cloud API only. Numbers connected via WhatsApp Web (QR code) cannot make or receive SIP calls — Meta's calling API requires Cloud API.