Android Pax a920Pro POS App Developer

I need professional expertise in developing a robust Android-based POS application for Pax a920Pro with an emphasis on secure payment gateway integration. Essential features should facilitate the use of credit cards for user transactions.

Ideal skills and experiences for this role:
- Profound software development with SDK
- Integrate built-in creadit/debit card reader via slip, chip, nfc.
- Proficient knowledge of Android App Development
- Prior experience designing and building Payment Gateway applications
- Understanding of credit card processing systems
- Implementation of secure protocols to protect sensitive data

P.S.: We want to create React Native Native Module to manage device over react native.