Turning handwritten cash books into QRIS-powered digital transactions.
A web-based point-of-sale solution built with Next.js and Firestore, integrated with the QRIS payment gateway, that converts manual cash transactions into digital ones with automatic sales recording — built for campus business partners still tracking payments by hand.
What needed to change
Business partners on campus had already adopted QRIS for digital payments, but every transaction still had to be copied by hand into a cash book afterward. The real problem wasn't accepting digital payments — it was that no system connected the payment to the record.
I studied how QRIS actually works end-to-end, from dynamic QR generation to the payment verification callback, then designed Next.js API endpoints to handle the full transaction flow reliably. Because the frontend cashier interface and backend payment logic were tightly coupled, optimizing Firestore queries for sales reports meant constantly reconsidering how that data would render on screen.
The result is a responsive cashier interface with real-time payment notifications powered by Firestore data sync, replacing manual bookkeeping with automatic, always-current sales records the moment a QRIS payment clears.
From concept to working solution
Payment confirmation via Firestore sync
Handwritten cash book entries eliminated
