Mobile App Development with Payment Integration

I'm looking for an experienced front-end and back-end developer to create a mobile app for both Android and iOS platforms. The main functionality of the app will be payment processing.

Key Requirements:
- User authentication via email and password
- Payment processing integration for:
- Credit/Debit cards
- Google Pay/Apple Pay
- Razorpay
- PayU
- UPI

Ideal Skills and Experience:
- Proficiency in mobile app development for Android and iOS
- Strong experience in payment integration and handling user authentication
- Familiarity with Razorpay, PayU, and UPI is a plus
- Ability to deliver a secure, user-friendly, and efficient payment processing experience