A QR code is a scannable optical label read by a camera in line of sight. QR payments need one deliberate scan, and the standard sits within the barcode work maintained by GS1.
The longer version
A QR code is a square pattern a camera can read. It is optical, so it needs line of sight and enough light, and the reader has to be aimed at the code. GS1 maintains the barcode standards that QR codes belong to. In payments, the customer or the merchant presents a code and the other side scans it.
QR payments are cheap to deploy because they need no special reader hardware, only a camera. That is their strength in many markets. The cost is the gesture: someone has to open a camera or app, frame the code, and confirm, which is a deliberate, aimed step much like a tap.
Proximity payment removes the aiming. Instead of lining up a camera on a code, the payer is recognized by presence over a short range signal, and the transaction routes through a server. QR proves intent through a scan, while a presence method proves nearness through a signal and waits for the payer to act.
The Parousya method
A QR code needs a deliberate scan in line of sight. The Parousya method replaces that aimed step with presence over a short range signal, then routes the transaction through a central server.