Greetings !
Well LEVELUP is no where a chore for even a Sage developer like me, ;)
I'm Sagar, working as a solution architect with an IT house, working for 7 years with Banks and eCommerce clients, made us learn that PAYMENT GATEWAYS are "bottlenecks".
As an Software guy, it's my suggestion, before you begin this project not essential with me but be 100% sure for the payment online, have communication with desired parties, your target audience and payment norms with govt.
Technically, We should move with Cordova's Ionic framework, Phonegap, reason being you desire effective and efficient solution, and nothing in particular a rocket science.
Thanks & Regards,