Customizing Your Line Item Properties

When a customer orders a customized product, Shopify needs to know which details to attach to that line item, for example, the design a customer created, the text they entered, or a print-ready file. Line item properties are how Fancy Product Designer passes this information to your Shopify order, and you decide exactly what shows up.

Understanding Your Line Item Properties

Every time a customer adds a customized product to their cart, Fancy Product Designer automatically attaches everything needed to transport their design data. These properties are added invisibly and always included. Nothing you configure in the app changes that.
On top of these, Fancy Product Designer offers simple toggle switches for a few additional, human-readable properties, like custom text and image counts, a print-ready PDF link, and asset links. You can find them under Global Settings > Integration > Integration, separate from the Building Blocks tool described below.
These toggles are turned off by default, which means those links and info don't show up in your order.

Finding the Building Blocks Tool

The Line Item Properties Building Blocks tool lets you build your own custom properties from scratch, going beyond the basic toggles above.

1. Navigate to Global Settings > Integration > Integration > Cart Page.
2. Open the "Line Item Properties" section.

Each block you set up here controls one property that gets attached to the order once a customer adds a customized product with this property to their cart.

Adding a Preset Block

We built six ready-made presets to cover the most common use cases: Custom Texts, Fonts, Uploaded Images, Designs, Layouts, and Customization Price.

1. Click "Add from library."
2. Select the preset block you want to use.
3. Use the up and down arrows to reorder blocks if the order matters for your workflow.
4. Click "Save" to apply your changes.

Blocks currently not needed can be deactivated by unchecking the checkbox in front of the block.

Need Something Different?

Sometimes the presets don't cover exactly what you need, or you want to change how an existing preset behaves.

• Creating a custom block: Click "Add custom block" and write your own JavaScript to define what data gets attached. Use "Test run" to preview the result against a sample order before saving.
• Editing a preset block: Presets can also be adjusted through their underlying code, not just the toggle.

Troubleshooting: Why Don't I See My Line Item Properties?

If you added a property but can't find it in your cart, checkout, or order emails, check its name first.
Shopify hides any line item property whose name starts with an underscore (" _ ") by default in most themes. This is a Shopify convention, not something Fancy Product Designer controls. If you want a property to be visible to you and your customers, make sure its name doesn't start with an underscore. On the other hand, if you only want to see the property in the Shopify Order in your store, it should start with an underscore.

Key Takeaways

• Properties needed to transport your customer's design data are always attached automatically and invisibly; no app setting changes that.
• A few additional, human-readable properties (text/image counts, PDF link, asset links) are toggle-based and off by default under Global Settings > Integration > Integration.
• The Building Blocks tool under Cart Page lets you add fully custom properties using presets or your own code.
• Property names starting with " _ " stay hidden in most Shopify themes by default.

Updated on: 30/07/2026