WhatsApp OTP + Booking Confirmation Integration (Flutter Apps + PHP Backend) Bid your final price only no negotiations on msg

Project Summary ( bid your final price only no negotiations on msg )

We have:
• A customer mobile & web app (Flutter)
• A service man/technician mobile app (Flutter)
• A provider/admin web panel (PHP backend)

Currently:
• Booking confirmation only shows on the app screen.
• Login and other verification steps use SMS OTP (we DON’T want SMS OTP anymore).

We want to replace SMS OTP with WhatsApp-based verification and also send booking confirmation via WhatsApp.

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What We Need Built

WhatsApp Booking Confirmation

When a booking is successfully created and the “Booking Complete” screen appears (with booking ID):

The system must automatically send a WhatsApp message to the customer’s mobile number with:
• Booking ID
• Service name
• Date & Time
• Amount (optional)
• Link to view booking (optional)

Example WhatsApp message:
Hello! Your booking is confirmed ✔️
Booking ID: 75621
Service: AC Repair
Date: 25 Dec, 4:00 PM
Click here to view your booking: {{link}}

WhatsApp OTP Login (ALL Apps + Web)

Replace SMS OTP with WhatsApp OTP everywhere:
• Customer login (Flutter)
• Service Man login (Flutter)
• Provider/Admin login (PHP web)
• Any other OTP flows inside the system

Login Flow
1. User enters mobile number
2. System generates a 4–6 digit one-time login code
3. System sends the code via WhatsApp message
4. User enters the code in app/web
5. Backend verifies the code → user is logged in

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3️⃣ WhatsApp OTP for ALL OTP screens

Wherever OTP is used inside:
• Customer app and web app
• Service man app
• Provider/admin panel

→ Replace with WhatsApp OTP service