Why mixed carts cause trouble
A customer buys a T-shirt that is in stock and a jacket on preorder in one order. Do you hold the T-shirt for six weeks, or ship it now and pay for a second parcel later? Either answer is fine, but the customer needs to know which one before they pay. Otherwise they expect the T-shirt this week and email you when it doesn't arrive.
There is no single right policy. Shipping together keeps costs down, shipping separately keeps customers happy, and blocking mixed carts keeps operations simple. The point is to choose one and say so clearly in the cart.
What Shopify does by default
By default, Shopify's cart and checkout accept preorder and in-stock items together and create a single order. Nothing in the standard cart tells the customer that part of the order will ship later. You can split an order into several shipments when you fulfill it in Shopify admin, as described in Shopify's help on fulfilling orders, but that happens after the purchase.
| Approach | Customer experience | Your work |
|---|---|---|
| Do nothing | No warning in the cart | Answer questions after the fact |
| Text on the product page | Only seen if they read it | Hard to keep consistent |
| Mixed Cart rules | A banner or modal in the cart, plus line labels | Pick a mode once |
Step by step: set up Mixed Cart
- Open Mixed Cart
In the app, go to Mixed Cart. Make sure the Preorder app embed is on in your theme.
- Turn it on
Turn on Enable mixed cart. A live preview on the page shows the result as you change settings.
- Choose a mode
Under When a cart would mix in-stock and preorder items, choose one of the three modes below.
- Write the banner or modal
For the Allow modes, edit Banner text and the ship text. For Block mode, edit the modal Title, Body and both button labels.
- Label cart lines
Under Cart line badges, set the In-stock label, Preorder label and Ships-on label (
{date}is that line's ship date). - Save and test
Save, then add an in-stock product and a preorder product to your cart on the storefront to see the result.
The three modes
| Mode | What the customer sees | Good for |
|---|---|---|
| Allow — show a warning banner, ship together | A banner says the order contains preorder items. Ship-together text can show the latest preorder ship date with {date} | Low-value items, short waits, keeping shipping costs down |
| Allow — ship separately (in-stock ships now, preorder ships later) | A banner explains the split shipment using Ship-separately text. The order is tagged preorder-ship-separately | Stores happy to pay for two parcels to get in-stock items out fast |
| Block — ask the customer to clear the cart first | A modal stops the add to cart, with Clear cart & add and Keep my cart | Stores that want preorders as separate orders |
Styling options
- Warning banner (Allow modes): Banner text (required), Background color, Text color, Corner radius (px), Font size (px), and Auto-dismiss banner with Dismiss after (seconds).
- Block modal: Title (required), Body, the clear and keep button labels, plus colors, sizes and corner radius.
- Cart line badges: In-stock label, Preorder label, their colors, Ships-on label and Badge font size (px).
Example: a clothing store that ships in-stock items first
An apparel store runs preorders on outerwear while T-shirts and accessories stay in stock. It would rather pay for a second parcel than make customers wait weeks for a T-shirt.
- Mode: Allow — ship separately (in-stock ships now, preorder ships later)
- Banner text:
Your cart has items on preorder. - Ship-separately text:
In-stock items ship now. Preorder items ship when they arrive. - In-stock label:
In stock, Preorder label:Preorder, Ships-on label:Ships on {date} - Auto-dismiss banner on, Dismiss after (seconds)
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In Shopify admin, the warehouse filters orders by the preorder-ship-separately tag and fulfills the in-stock lines straight away, leaving the preorder lines for later.
Tips and common mistakes
- Match the mode to your shipping rates: if you ship separately, check that your shipping rates cover a second parcel.
- Use the ship date: the
{date}token is only useful when your preorder campaigns use Scheduled fulfillment with a date. - Block mode friction: blocking is the clearest policy, but it adds a step. Make the modal Body explain why, for example that preorder items ship separately.
- Keep the banner short: one sentence reads better in a narrow cart drawer than a paragraph.
- Check the cart drawer: test both the cart page and your theme's cart drawer after saving.
To give preorder lines a real ship date, see expected ship dates.
Frequently asked questions
Can customers buy preorder and in-stock items in one order?
Yes, in both Allow modes. Choose Block — ask the customer to clear the cart first if you want preorders bought on their own.
How do I know which orders to split?
In ship-separately mode, orders are tagged preorder-ship-separately. Every order with a preorder item is also tagged preorder.
What happens when a customer clicks Clear cart & add?
The existing cart is cleared and the preorder item is added, so it becomes its own order. Keep my cart leaves the cart as it was.
Can each cart line show a ship date?
Yes. The Ships-on label uses {date} for that line's ship date, when the campaign has a scheduled date.
Does Mixed Cart need its own app embed?
No. The single Preorder app embed powers Mixed Cart along with the preorder buttons.
