What it looks like

1. Staff tap Gift registry to open Listify, and close straight back to the till when they are done. Put the tile high on the grid: it scrolls, and anything below the fold gets forgotten.

1. Ring everything up first, then open Listify. Staff type the couple's name, or scan the QR code straight off the guest's phone, which is quicker and saves spelling a surname across a counter.

2. Matches appear from the third letter. Each row shows the couple, the occasion and the date, so staff can confirm they have the right one without asking the guest to prove anything.

3. What the couple still need comes first, each with a thumbnail and a one-tap Add to cart that drops the item into the sale already tagged, unless the giver still has a size or colour to choose. The basket sits underneath as a check on what has been attributed so far.

4. Tagged lines are marked on the spot. If a line already belongs to a different registry it says so rather than being quietly overwritten, which is the one thing worth catching before payment. An item whose size or colour the giver picks has no one-tap button, because the variant on the list is only a stand-in: staff choose the real one in POS.

1. Staff tap the line in the cart. Listify sits in the menu POS already shows there, so there is nothing new to remember.

2. The same search as before. The item being tagged is named at the top, so nothing on screen repeats what the clerk just tapped.

3. If the line is already on a registry, staff are told which one before they change anything. Choosing another moves it; Remove takes it off entirely.

4. Confirmed, and back to the till. Staff can attach any line this way, including something bought off-list as a gift, which is the case a strict match would miss.

1. Open the product, by scanning it or searching POS for it. Buying for a registry is one more option on the menu POS already shows, so there is nothing new to remember.

2. The item appears first, so staff can confirm they have the right variant while every registry in the shop is checked against it. POS draws its own progress bar, and it sits centred under the item.

3. Two registries have this exact item on their list. One tap adds it to the sale already tagged to that registry and closes back to the till, so nobody spells a surname across a counter.

4. Nothing on any list matches. Staff get a plain answer instead of an empty screen, and there is no search box to puzzle over, because there is nothing to narrow.

5. The way out when the guest says it is a gift anyway. Searching by name does the same thing as before: the item goes into the sale tagged to that registry. Buying something off the list is an ordinary gift, and it lands on the registrant's orders like any other.

1. The receipt screen confirms what was recorded and that the registrant has been emailed. Staff can tell a guest their gift is on the list without opening anything.

2. Not an error. Shopify tells us about a sale a moment after it completes, so the screen occasionally gets there first. The registry catches up on its own within seconds.

1. A scan that matches exactly one registry opens it straight away, with no confirming tap. Hardware and counter-mounted scanners work the same way as the camera.