Backend for Garage Booking MVP

The entire front-end is already in place for my multi-vehicle repair booking app; what I now need is a solid backend that glues everything together. I want you to design and code all server-side logic so customers can quickly connect with nearby garages, pick a time slot, and confirm the job.

Core flows
• Two distinct user roles—customer and garage—must be handled cleanly. A customer should be able to create a booking, modify or cancel it, and review past jobs, while a garage can accept, reschedule, mark as completed, or reject requests.
• Phone-number authentication is mandatory. I’m expecting an OTP-based flow that is both secure and friendly for non-tech users.
• All payments will run through a bank-transfer gateway. You’ll set up the integration, listen for webhook confirmations, and update booking states accordingly.
• PostgreSQL is our data store. Please create the schema, write performant queries (CRUD + reporting), and expose everything through well-structured endpoints (REST or GraphQL—your call, as long as it is documented).
• The code must be production-ready, with clear separation of concerns, environment config files, and short but useful inline comments.

Deliverables
– Full source code in a Git repository
– Database schema and seed script
– API documentation (Postman collection or Swagger)
– A brief deployment guide for a Linux server

If you have experience building transactional systems with phone OTP and bank-transfer integrations, let me know; otherwise, a short outline of your proposed tech stack and timeline will help me pick quickly.


Tech
Flutterflow
Dart program
Supabase
Nodejs