A line item property is a custom detail Shopify stores on one cart line: engraving text, a size, a link to an uploaded file. Your options app writes each shopper choice into one.
Anything that rebuilds a cart line from the variant alone brings back the product and none of those details. That is how custom options go missing at reorder, at cart edit and at abandoned cart recovery. Appify Custom Product Options keeps the configuration attached to the line, so Reorder, Edit options and Restore your cart all bring the choices back.
What is a line item property on Shopify?
Shopify's own docs describe it as custom information you add, or let customers add, to a line item. A theme adds one with an input named properties[Engraving], and the property then travels with that line.
Shopify shows these properties in the cart, at checkout and on the order. Two more facts from Shopify's docs matter for everything below:
- Different properties make different lines. Two identical items with different properties sit in the cart as separate line items.
-
An underscore hides a property. A name that starts with
_is hidden from the customer at checkout, but it still appears on the order details page in the Shopify admin.
The variant says which product. The properties say which version of it. A 24 by 36 inch vinyl banner with hemmed edges and a 24 by 36 inch banner with grommets can share one variant and differ only in their properties.
What does one configured line carry?
With Appify Custom Product Options, the shopper's choices become the line's properties. In Cart properties you pick which ones go to the cart and order, in what order, and whether names follow the shopper's language. Here is one banner line:
| Property | Customer sees it? | What it does |
|---|---|---|
| Size: 24 x 36 in | Yes | Shows on the cart, at checkout and on the order |
| Material: Vinyl | Yes | Same |
| Area (a variable you add) | Yes | Shows the computed area, formatted the way you choose |
| Cut width (Admin only) | No | Your team sees it on the order |
| Design Files | Yes | A link to a summary page with downloads and production details |
| _state | No | A short hidden id that lets the app rebuild the configuration |
Property names and values are an example. Your calculator decides what each line carries.
The last row is the one that matters after the order. The app stores a hidden _state id on each customized line when it is added to the cart. That id is how a reorder rebuilds the exact configuration.
Why do custom options get lost at reorder?
Shopify's Buy again button adds the variant and drops the original configuration. The new cart line has the product and no properties, so the 24 by 36 inch hemmed banner comes back as a plain banner. The shopper has to rebuild it from memory.
Appify Custom Product Options has three reorder surfaces, and each one rebuilds the saved configuration:
- Order confirmation email. A Reorder this item link under a customized line adds that configuration to the clicker's cart. It adds. It does not empty the cart.
- Customer accounts. The Appify Reorder block sits on the Orders and Order status pages. Turn Shopify's Buy again off first.
- The app's Orders page. You can reorder one line, or use Add Order to Cart to rebuild the whole order.
If the published calculator changed since the first order, the shopper reviews the filled-in options before the line goes in. The full story is in why Shopify's Buy again button drops custom options.
Why do custom options get lost at cart edit?
A shopper adds a banner, then realizes it needs to be smaller. Removing the line and starting over loses every choice they made.
A hand-built edit has its own trap. Shopify's docs say a change.js cart API request that includes properties overwrites the entire properties object.
With Edit options, the shopper clicks the button on the cart page or drawer. A full-screen editor opens on the current published calculator with their saved selections filled in, quantity included. They change the size and click Update.
The app adds the updated line and removes the previous product and its linked fee line. Lines that came back through a reorder or a recovered cart can show Edit options too. More in how to let customers edit configured products in the Shopify cart.
Why do custom options get lost at abandoned cart recovery?
Shopify's default abandoned checkout button points at a checkout or cart permalink. The customer clicks it and the cart comes back with the products and none of the options. That is confusing for the shopper, and for you it is a recovered cart that still needs a conversation.
The fix has two parts, set up in your abandoned checkout and cart emails:
-
Options in the email. When the email editor can print line item properties, each product lists the options the shopper chose. Names that start with
_stay hidden. -
A Restore your cart button. The app saves a recover ID on the cart as
_recover. The button opens a page on your store that clears the browser's current cart, adds every abandoned line back with its options, and lands the shopper on the cart.
It restores the whole cart, customized products and regular ones together. If one calculator changed, the clean lines are added first and that line waits for a short review. The email setups are covered in abandoned cart recovery that keeps product customizations.
Which line item properties should you show?
You choose what each line carries. In Optional Features → Cart properties you can:
- Uncheck an option to keep it on the product page and off the cart and order.
- Add a computed value, such as area, with a display name customers understand.
- Mark a row Admin only so your team sees it on the order and the customer does not.
- Reorder the rows to match how your team reads an order.
Admin only rows are sent with a name that starts with an underscore, the same Shopify convention described above. Options hidden by a visibility rule are never sent at all.
FAQ
What are line item properties on Shopify?
They are custom details attached to a single cart line, such as engraving text or a size. They show in the cart, at checkout and on the order.
Can customers see properties that start with an underscore?
Not at checkout. Shopify hides them there, and they still appear on the order details page in your admin.
Does Shopify's Buy again keep custom options?
No. It adds the variant and drops the original configuration. Appify Reorder rebuilds the saved configuration instead.
Can I show custom options in abandoned checkout emails?
Yes, when the email editor can print line item properties. The Restore your cart button then brings the whole cart back with its options.
Can shoppers change a configured product after adding it to the cart?
Yes. Edit options opens the current calculator with their selections filled in, and Update replaces the old line.
Every option, still there at reorder.
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