Order line properties

Personalization travels through Shopify as standard line item properties. This page documents exactly what the app writes, for merchants who print packing slips, build flows, or integrate with fulfillment tools.

Merchant-visible properties

These appear in the cart, the Shopify admin order view, confirmation emails and packing slips:

Property	Content
Engraving (or your field’s label)	The customer’s text, verbatim. One property per filled field, named after its label.
Font	The font the customer chose (e.g. Great Vibes).
Color	The color’s label from your palette.
Gift box	Present when the gift-box option was selected.
(swatch label)	The selected swatch option (e.g. Finish: Matte).
(image field label)	The URL of the customer’s uploaded file, hosted by Shopify.
For: (product title)	On fee/gift lines where applicable, indicates which product the line belongs to.

Field labels are the ones you configured, in the storefront’s language — so your packing slips read naturally.

Technical properties (_-prefixed)

Properties prefixed with _optan_ are hidden from customers by Shopify convention (themes don’t display underscore-prefixed properties). The app uses them to guarantee fidelity and reconciliation:

Property	Purpose
_optan_config_version	Schema version of the configuration that produced the line.
_optan_field_…	Stable per-field identifiers backing the visible values.
_optan_fee	The surcharge amount attached to the line, used by the Orders page display.
_optan_font_id, _optan_color_hex	Exact font/color snapshot at purchase time — what makes production SVGs faithful even if you later edit the product’s palette.
_optan_fee_variant, _optan_gift_variant	References that let the Shopify Function build the inseparable bundle.
_optan_fee_error	Written only if the fee could not be attached, so the sale proceeds and you can reconcile later.

Don’t strip underscore properties

Some cart-editing apps or custom theme code remove properties they don’t recognize. Stripping _optan_* properties breaks the fee bundle and production-file fidelity. If you run another cart-manipulating app, test an order end to end.

For integrators

• All properties are plain strings on the order line — readable via the Admin API, Flow, or any app that consumes line item properties.
• Uploaded-image properties contain a URL to Shopify’s CDN; download it server-side if your workflow archives artwork.
• The app also stores a normalized copy per order (product, variant, fields, font, color, fees) that powers its Orders page and CSV export — the CSV is the most convenient integration surface if you don’t want to parse properties yourself.