Scan and go is a way of shopping in which the shopper scans each item on their own phone while walking the aisles, pays in the app and walks out without queuing at a counter. It is also called mobile self-checkout, or scan as you shop. It is used mainly by supermarkets and fashion stores in the United Kingdom, the rest of Europe and the United States.
The shopper uses either the store's own app or a web page opened from a QR code at the entrance. The phone's camera reads each item's barcode. The app looks up the price in the store's retail POS system, so the price is the same as at the counter. The basket total updates as the shopper goes.
Say a shopper in Manchester, in the United Kingdom, needs a shirt and a pair of socks. She scans the QR code at the door, and the store's page opens on her phone. She scans the shirt, at £25, and the socks, at £6. She pays £31 in the app, by card or with the wallet on her phone. The payment goes through the store's payment gateway, like any online payment. The app then shows a green exit pass, a QR code that proves she has paid.
Two problems must be solved before she can leave. The first is the security tag on the shirt. In many fashion stores, the tag is an RFID tag, a small chip that a reader can read by radio, without touching it. When she pays, the store's system marks that tag as paid. The gate at the exit reads every tag that passes, and raises an alarm only for unpaid ones. The second problem is honesty. Stores check a few shoppers at random. A staff member scans the exit pass and compares the bag with the list of items.
Why do stores offer it? It needs no new machines at the counter, because the shopper brings the phone. It also removes the queue, which shoppers dislike most about a store. And if the shopper is logged in, the store learns what she bought.
Scan and go differs from a self-checkout kiosk. At a kiosk, the shopper still queues, and scans everything at the end on the store's machine. With scan and go, the shopper scans on their own phone while shopping. A cashierless store removes even the scanning. In India, scan and go is still rare, and most shoppers pay at a staffed counter.