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Systems Architecture ⏱ 5 min read Sep 29, 2026

Two-Way WhatsApp Calendar Sync with Google & Outlook

A technical walkthrough of two-way appointment scheduling syncing official WhatsApp webhooks with Google Calendar and Microsoft Outlook APIs.

MA
Mohammad Altmash Full-Stack Engineer · Laravel & Django
Deep Dive & Analysis

The Disconnected Calendar Dilemma

When consultations and appointments are scheduled via WhatsApp messages, staff manually open Google Calendar or Outlook to verify doctor or consultant availability. When changes happen, the calendar and the chat desynchronize immediately.

The Automated Two-Way Sync Pipeline

  1. Slot Availability Query: When a client requests an appointment on WhatsApp, the backend queries the Google Calendar FreeBusy API to fetch live available time slots.
  2. Instant Hold & Hold Expiry: Selected slots are temporarily reserved for 10 minutes to prevent double-booking while the client completes payment or confirmation.
  3. Event Generation: Upon confirmation, the backend writes directly to Google Calendar/Outlook with client contact details, Google Meet link, and automated reminders.
Architecture Discussion

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Written by Mohammad Altmash Full-Stack Engineer · Laravel & Django · WhatsApp CRM & Clinic Systems Architect
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