How do cart controls and the no-checkout-qty tag work?

Cart controls add a small link under each item in checkout, by default Modify. Clicking it opens a quantity stepper, so the buyer can change how many they're buying without going back to the cart.

Set it upCopy Anchor Link

1. In Upsell Master, go to Checkout.
2. On the Cart Control card, click Edit Cart Control Widget.
3. Create a widget. Under Display Text, enter the link text buyers will see.
4. Under Controls, turn on Show Quantity Selector.
5. Save, then make sure the Cart Controls block is placed in Shopify's checkout editor.

What the buyer can doCopy Anchor Link

• Change the quantity with the stepper. The cart and total update straight away.
• Set the quantity to 0 to remove the item.

The control doesn't show when the checkout total is 0.

Settings that don't change checkout yetCopy Anchor Link

The form has more options than the checkout block uses today:

• Show Variant Selector and Allow Subscription Update are saved, but the block only shows the quantity stepper.
• Position can't be changed. The control always appears under each cart item.
• Alignment doesn't change how the control is shown.

Stopping quantity changes for a productCopy Anchor Link

Some products shouldn't have their quantity changed in checkout, such as a free gift, a sample or a bundle. Tag them so cart controls skip them:

1. In Shopify admin, open the product.
2. Add the tag no-checkout-qty.
3. Save.

On a tagged product's cart line, the Modify link doesn't appear at all. Every other line in the cart keeps it.

• The tag isn't case-sensitive, and spaces around it are ignored. No-Checkout-Qty works too.
• Adding or removing the tag can take up to 5 minutes to show in checkout.
• If the app can't check the tags, for example during a Shopify outage, it shows the control as normal rather than hiding it.
• The tag only affects Upsell Master's cart controls. It doesn't change Shopify's own cart page or other apps.

A/B testingCopy Anchor Link

You can split-test cart controls with Create A/B Test. One variant can be a Blank split test widget, which shows nothing, so you can measure whether the control helps. See Analytics for results.