Required Square API,Phone,Payments,Android freelancer for Custom Android App Development job

I am looking for an experienced android app developer to build a custom application for a proof of concept I am exploring. The application will integrate with both an external card reader (hardware from SumUp) as well as SumUp itself (software) to process the payment transaction. Experience building custom apps with payment processing vendor integration (e.g. Square, Stripe, etc.) is a huge plus. The application should also utilize a hosted/centralized back-end database that can be accessed both by the mobile app as well as via the web. Details of the required screens, functionality and process flow will be provide after hiring. Competitive hourly rate with periodic checkpoints to review process preferred.

Skills & Expertise Required

Square API Phone Payments Android