Hi,
Let me introduce myself.
I'm a backend and frontend programmer with more than 10 years of experience developing the most different kind of projects.
I have 10+ years of experience with Java technologies, building solutions using JSE, JEE and J2ME.
Over 5 years of project coordination.
5+ years of experience with Android.
3+ years of experience with PHP, MySQL, PostgreSQL, HTML, CSS and Ajax.
I have already done project using QRCode scanner and online payment.
My only concern here is about the users account for payments. Once it is not specified here.
But, if there is a documented API, no problem, I can do it for you in 3 or 4 days.
I'm available to talk more about this project.
Kind regards,
Fabio Bergmann