Flutter Lab Booking App

I’m putting together a straightforward Flutter application that lets patients book diagnostic tests and track everything from one place. The same codebase must compile cleanly on both Android and iOS, so please keep platform-specific tweaks to a minimum.

Core flow
Users sign up or log in with their phone number; an OTP verifies them and drops them straight onto a catalogue of available tests and health packages. From there they can schedule an in-lab visit or request home sample collection, pay, and watch the status progress until the final report is ready to download as a PDF.

Essentials I need delivered
• Clean Flutter code (latest stable) that builds for Android & iOS
• Firebase or equally reliable backend for phone-OTP auth and push/WhatsApp notifications
• Booking module with date-time picker, price display and coupon placeholder
• Integrated payments: Credit/Debit Card, UPI, and Net Banking via a popular Indian gateway (Razorpay or similar)
• Order status tracking screen with simple colour-coded stages (Confirmed, Sample Collected, Processing, Ready)
• Report repository where users can tap to view or download the PDF
• WhatsApp message trigger at each status change (template messages provided)
• Lightweight admin panel (web or Flutter web) for test catalogue, price edits, order overview, report upload and status updates
• Basic but neat UI; I’ll hand over a style guide and logo
• Build, signing and store-ready files plus a brief hand-off document

Acceptance check
1. I can register, book, pay, receive WhatsApp alerts, and download a dummy report on both Android and iOS simulators.
2. Admin panel lets me add a new test and update an order without touching the database directly.
3. Payment flows succeed in test mode for the three methods listed.
4. No critical warnings in Flutter doctor; code is commented and handed over in a private Git repo.

My initial budget is ₹20,000, so please structure milestones accordingly and keep external subscription costs minimal. If everything runs smoothly, I’m open to ongoing feature work later.