Android Recharge & Bill Pay App

I need a full-featured Android application that lets users top up their mobile phones, recharge DTH subscriptions, and pay routine utility bills—all in one place. Smooth, secure sign-in is mandatory, so the sole authentication flow will be phone number verification followed by an OTP. The core work involves: • Building a modern Android UI that guides users quickly from login to successful payment • Integrating reliable recharge / payment APIs for prepaid mobile, DTH, and multi-bill categories • Adding a payment gateway that supports cards, UPI, and wallet options common in India • Implementing a robust backend (custom or Firebase) to store user profiles, transaction history, and OTP logic • Delivering clean, well-documented source code plus a signed release APK Acceptance criteria • Phone-number-only login generates and verifies OTP within 20 s • Successful real or sandbox transactions for all three service types • Error handling and status updates (pending, success, failed) clearly visible to the user • Code compiles in the latest stable Android Studio and passes Play Store checks If you have prior experience with recharge APIs and OTP-centric flows, I’d love to see your work and discuss timelines.